historical research report

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HISTORICAL RESEARCH REPORT
Research Report TM/79/09
1979
Autopsy study of coalminers’ lungs. Final
report on CEC Contract 6244-00/8/103
Davis JMG, Chapman J, Collings P, Douglas AN, Fernie J,
Lamb D, Ottery J, Ruckley A
HISTORICAL RESEARCH REPORT
1979
Autopsy study of coalminers’ lungs. Final report on
CEC Contract 6244-00/8/103
Davis JMG, Chapman J, Collings P, Douglas AN, Fernie J, Lamb D,
Ottery J, Ruckley A
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INSTITUTE OF OCCUPATIONAL MEDICINE
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ii
Report No. TM/79/9
(EUR. P2?)
CEC Contract
62Ulf-00/8/103
UDC 616.2^-003.6
FINAL REPORT CN CEC
CONTRACT 62^-00/8/103
AUTOPSY STUDIES OF
COALMINERS1 LUNGS
J.M.G. Davis
J. Chapman
Paula Collings
A.N. Douglas
June Fernie
D. Lamb
J. Ottery
Anne Ruckley
April 197«
2 1 MAY i9
(ii)
Report No. TM/79/9 (EUR. P2?)
CEC Contract 62M4-00/8/103
I N S T I T U T E
O F
O C C U P A T I O N A L
M E D I C I N E
AUTOPSY STUDIES OF COALMINERS' LUNGS
J.M.G. Davis, J. Chapman, Paula Collings, A.N. Douglas,
June Fernie, D. Lamb, J. Ottery and Anne Ruckley
FINAL REPORT ON CEC RESEARCH CONTRACT 62^-00/8/103
(SECOND PROGRAMME ON CHRONIC RESPIRATORY DISEASES)
Duration of project:
August 197^ to July 1977
Research work carried out with financial aid from the
Commission of the European Communities and the
British National Coal Board.
Institute of Occupational Medicine,
Roxburgh Place,
EDINBURGH
EH8 9SU
(Tel. 031-667-5131)
April 1979
(lit)
Report No. TM/79/9
EUR. P27
CEC Contract 62^-00/8/103
UDC 616.24-003.6
by
J.M.G. Davis, J. Chapman, Paula Collings, A.N. Douglas,
June Fernie. D. Lamb. J. Ottery and Anne Ruckley
CONTENTS
Page No.
SUMMARY
(iv)
1.
INTRODUCTION
2.
MATERIALS A N D METHODS
3.
DESCRIPTION OF CASES
16
k.
A COMPARISON OF PNEUMOCONIOSIS FOUND
AT AUTOPSY WITH LUNG DUST CONTENT AND
LIFETIME DUST EXPOSURE
25
A COMPARISON BET'.ilEEN LUNG PATHOLOGY
FOUND AT AUTOPSY AND CHEST RADIOGRAPHS
OBTAINED DURING LIFE
59
5.
6.
7.
1
.
.
FACTORS AFFECTING EMPHYSEMA IN THE
LUNGS OF 1+50 COALMINERS
.
.
.
.
.
9
89
DISCUSSION
113
ACKNOWLEDGEMENTS
123
REFERENCES
125
APPENDIX A
131
APPENDIX B
APPENDIX C
(iv)
Report No. TM/79/9
FINAL REPORT ON CEC CONTRACT 62*^-00/8/103
by
J.M.G. Davis, J. Chapman, Paula Ceilings, A.N. Douglas,
June Fernie, D. Lamb, J. Ottery and Anne Ruckley
SUMMARY
This report is based
coalminers who had. worked
the British National Coal
Study. These collieries
in the United Kingdom.
on the examination of lungs from 500
in 25 collieries that were involved in
Board's Pneumoconiosis Field Research
were chosen from all the mining areas
The study group of 500 cases is not typical of all miners
involved in Pneumoconiosis Field Research being biased in favour
of selection of older men with established pneumoconiosis.
For
each set of lungs detailed estimations were made on the number
and types of dust lesion or areas of emphysema and the dust content
of one lung was extracted for mineralogical analyses.
For the
purpose of this report the cases were classified into three pathological types based on macroscopic examination: those with only
soft dust macules (M), those with in addition one or r.ore r>alrv?b].e
small fibrotic nodules (F) and cases with nodules larger than 1 cm
(PMF).
Pathological findings were compared with the lung dust
content at death as well as lifetime estimates of dust exposure.
I'll s'Jftiti'ji"' olitrSt i''i-.uiOf.j;i'a.pl:b Ic'keii teh'jrll.y \jtiiQi~v dectlh, v.'hei'S
these were available, were compared to the types of pathology found
at autopsy as well asfto the lung dust content. The main
conclusions from each group of studies are presented in three
chapters and may be summarised as follows:A comparison of pathological types of pneumoconiosis found at
autopsy with lung dust content and lifetime dust ex-nosure
For the whole group of cases the mean weights of all types of
mineral dust present in the lungs increased between the pathological
types M, F and PMF although there was considerable variation within
each category.
When the collieries were divided into six groups defined by the
rank of coal mined it was found that in cases from all rank groups
the mean lung weights of each mineral increased between the three
pathological types but the level of increase varied considerably.
For cases with either macules or fibrotic nodules the total dust did
not differ significantly between the rank groups.
For cases with
PMF, however, those from the highest rank group contained
significantly more dust than those cases from other rank groups.
(v)
The mean coal content of lungs with PMF decreased
progressively with decreasing coal rank.
Cases with fibrotic
nodules showed some differences between collieries mining the
highest and lowest ranks of coal but the coal content of lungs
with only soft macules did not differ between rank groups.
The highest lung weights of non-coal mineral within any one
pathology class were found in cases from collieries mining coal
of relatively low rank.
There were no significant differences
in the percentage coal or mineral composition of lung dust with
differing levels of pathology in the high rank collieries.
In
low rank groups, however, the percentage coal decreased between
the lesion types M, F and PMF and the percentage of non-coal
minerals was increased.
moo u ui
LUC ucioco O U U I A J . G H unj-j" o.
their lifetime dust exposures had actually been measured during
the Pneumoconiosis Field Research Study.
In 119 cases, measured
dust exposures were available for at least 20 per cent of their
working lives.
When these cases were considered as one group,
the pathological types of lesion present at autopsy showed little
relationship to estimates of lifetime dust exposure.
Some
exposure differences were seen when cases were divided into four
coal rank groups with PMF cases from high rank collieries
appearing to have been exposed to more dust than those from low
rank, but the differences were not significant.
These and
subsequent observations are dependent on the accuracy of estimated
past dust exposure.
Some linear regression analyses have suggested that the
retention of the various dust components per unit of exposure did
not differ significantly between rank groups for cases with
fibrotic nodi.il PR.
For PMF cases, however, it was found th£'t the
lowest retention of non-coal minerals had occurred in collieries
mining the highest rank of coal.
The highest retention of noncoal minerals was found in men from the medium to low rank
collieries.
When the percentage composition of lung dust was
compared to that of the mine dust to which the man was estimated
to have been exposed it was found that there was a higher
proportion of the ash components quartz, kaolin and mica in cases
with either fibrotic nodules or PMF from low rank collieries but
not from high.
A comparison between lung pathology found at autopsy and chest
radiographs obtained during life for 261 cases
A comparison of radiographic profusion of small rounded
opacities and pathology grading showed that 83% of cases with soft
dust macules were categorised as 0/0.
Thirty-two per cent of
cases with fibrotic nodules were also categorised as 0/0, although
one quarter of these cases did show small irregular opacities.
Work in progress will test the hypothesis that F cases classified
as 0/0 contain lower numbers .of measurable nodules than other
cases in that group.
Counts of total dust foci tended to increase with increasing
radiographic profusion of small rounded opacities.
The overall
correlation betv/een radiographic category and counts of foci was
(vi)
0.'43. The comparability between radiographic classification and
pathological findings in PMF cases was extremely good for the
large category G opacities but less exact for category B lesions.
For the smaller category A opacities there was considerable
variation among the four readers used and 21 out of 37 cases with
lesions between 1 and 5 cm observed pathologically were not
recorded on X-ray by any reader.
With increasing X-ray category of simple pneumoconiosis, there
was a significant increase in lung dust content and its components.
However, cases with category 2 or 3 simple pneumoconiosis had
higher dust levels than cases with category A or B Fl-'F defined
pathologically.
The lung dust from cases classified as category
0 contained a higher nroportion of coal and a lover proportion of
~~u
4-1
-,„.!
_.. i _„.—„
T.I_ „
~.: 4.^
T J.: rr~~.~~~~r. ,.-,„„
found between categories 1, 2, 3 and PMF.
No significant systematic variation v/as found between the
radi.ographic category for the profusion of small rounded opacities
and the degree of emphysema.
However, for cases showing small
irregular opacities there v/as a significant increase in emphysema
v/hen compared with cases categorised as 0/0 for this type of opacity.
Cases with a p type of small rounded opacity were more
frequently associated with emphysema, had a higher mean count of
dust foci and higher levels of lung dust than cases with q or r type
lesions. The rror.ortion of coa] in lung dust decreased and that of
ash increased between cases with the p and those with q and r types
of small rounded opacity.
These findings are based on an average
classification of opacity type which is not wholly satisfactory.
Further work will examine the data in a more detailed and accurate
manner.
Factors affecting the occurrence of emphysema in the
lur.rs of ^30 cooTnjners
Cut of the total of 500 cases, '~'jD h^d both emphysema
estimations and smoking history available. Ermohysema was estimated
by the method of Brian Heard.
In this group of coalminers the
prevalence of emphysema v/as seen to be age-related for smokers but
not non-smokers, although only ^5 cases fell into the latter
category. The percentage of cases showing any emphysema increased
between the pathological types of pneumoconiosis M, F and PMF. The
overall figures, were ''7Y- for M cases, 6'$ for'' F cases and 82$ for
PMF cases. Smokers, ex-smokers and non-smokers all showed this
effect but to a variable degree.
This is part of n conmlex
relationship between age, smoking habit and lung dust content which
is explored in the text.
It should be emphasised that this
association refers only to the presence of emphysema and not to the
extent of this condition.
Tn 1?1 smokers aged between 66 and 75 there was no linear
association between the extent of emphysema and the lung dust content
or its composition.
In hk smokers from this group for whom satisfactory dust exposure data were nvailahle there was no simple
relationship between the mass and the composition of inhaled dust and
the extent of emphysema. Work will now be directed towards
quantisation of the extent of the different types of emphysema and
their association with dust deposition and pneumoconiotic disease.
1.
INTRODUCTION
Coalworkers' pneumocor.iosir. has been studied for many yeers but
the relative importance of a number of factors reputed to be involved
in its development is still uncertain.
"Black lung" was recognised
as a disease of coalminers in Britain over 300 years ago (EVELYN,
1661)
but knowledge of the important parameters of disease production
progresses slowly.
Black deposits of inhaled carbonaceous material
were reported in human lungs by PEARSON in 1813.
A similar
observation was made by LAENNEC in 1819 when he distinguished black
tumours.
GREGORY in 18J1 reported large fibrotic deposits with
cavitation in the lungs of men who had inhaled considerable amounts
of coal dust, and CRAIG in 183^ reported that the air sacs close to
areas of deposited pigment were often dilated affording what is
probably the first report of focal emphysema.
In the same year,
GRAHAM reported on the chemical analysis of the carbonaceous material
from coalminers' lungs and claimed that most of it was lamp black.
MARSHALL (18J3-183'0 suggested that coalworkers' pneumoconiosis
initially evolved from small deposits of inhaled dust but later large
masses of black consolidation occurred which might soften with
resulting cavitation.
GIBSON (1833-183M introduced the idea that
the large pigmented masses night be due to the superimposition of
tuberculosis upon the initial dust lesion and f-'AKEJ.LOR in 18^5
supiyji-Led Lido iues of "V.Tsr.k v-V.t.V-;.-:; 3" G;; greeting thrvt this diccnse
was more common in men who had worked with stone as well as coal.
As an alternative to the tuberculosis theory of development for
severe pneumoconiosis some workers suggested that dust alone was
sufficient to produce the observed changes.
TRAUBE in i860
considered that inhaled dust particles penetrated into the interstitial space because of their sharp edges but because coal dust was
observed to produce little tissue reaction he suggested that the
mechanical effect alone could not explain the full development of
pneunocor.iosis.
Later, however, GRKENLAW (1869) attributed the
pulmonary reaction in pnoumoconiosis to the mechanical irritation of
dust in both coal ond stone workers.
In 1?67 ZENKER, using rounded
particles of iron oxide, rtemorRtmted that it was not necessary for dust
particles to be sham in order to penetrate into the tissue spaces
but it was not until 1923 that GARDNER was able to prove that sharp-
2.
edged narticles of silicon carbide produced no tissue reaction and that
noro than a mechanical effect was required to nroduce pneumoconicsis.
GROCQ in 1862 suggested that coalworkers' pneur.oconiosis resulted from
a simple accumulation of dust in the lungs without tissue inflammation.
From this period, detailed knowledge of the pathology of
coalworkers1 pneumoconiosis was slow to develop and as late as 19'*2
BELT and FERRIS described the early dust lesions as diffuse.
suggestions had already been made by HUSTXN (1931);
GARDEN (1935) and WALSCH (1938).
miners was focal.
STE'.vART ( 193'0 ;
Earlier, however, CUMMINGS and
This view was subsequently repeated by GOUGH
and WILLIAMS (19^0.
The final elucidation of the initial coal dust
lesion resulted from the work of HEPPLESTCN (19^7;
195'0.
Similar
1951; 1953 and
HEPPLE3TON demonstrated that the early dust lesions developed
from the accumulation of dust-laden phagocytes around the divisions of
the respiratory bronchioles.
With the passage of time reticulin
fibres
were laid down among the cellular aggregates, binding the cells together
and jr. more advanced Issions collngen fibres were often rresep.t.
tho ageing of the connective tissue shrinkage occurred.
''ith
At this stage
there could be two to five dust "macules", 1 - k mm in diameter, in each
secondary lobule.
The individual dust deposits, however, remained
.*>"•• <??_! so th''t ir fror-b 1'.ir~ nroî^'vr.s tho "m^cMlt-'s"
to'ich.
folt. so ft to
tho
In nore advanced cases tho continued deposition of dust in
association with connective tissue fibres could lead to solid masses,
2 - 10 mm in diameter, which were hard to the touch rind give the lung a
"lumpy" feel.
Nodules trenching a size of more than 10 mm in diameter
were classed as progressive massive fibrosis.
HEPPLESTON showed that emphysema found in cases of coalworkers1
pneumoconiosis v;as so strongly localised to the vicinity of the focal
dust lesions that a cause and effect relationship appeared likely.
He
pointed out that early dust lesions do not show focal emphysema while
advanced cases often do, so that dust accumulation appeared to be the
primary change.
He suggested that emphysema follows as a secondary
effect probably due in part to the loss of elasticity of the dust
lesions plus their eventual fibrosis and contraction.
In I0**? KING and NAGELSCFKTDT published a report of the
exarr.i nation of lungs from ?'+ coalminers in South Wales.
The degree of
pulmonary pathology was compared to the lung dust content and the dust
' - ' • " • 3. '
analytical procedures included estimations of coal, quartz, kaolin and
mica.
They reported that while the lung dust of some men contained
over 95% coal, in others v;ho were classified as rock workers, the coal
level was as low as 25$ with a corresponding increase in other
minerals.
It was found that for a group of 2? anthracite workers the
percentage composition of the lung dust was very similar to that of
dust from the coalface and the authors therefore concluded that there
was no mineralogical change in the lung.
In this study the
pneumoconiosis cases were classified into three main pathological
groups:
reticulation, mixed nodulation and confluent fibrosis.
Three
rock workers were classified separately as cases of pure silicosis.
It was found that the concentrations of coal and quartz increased only
very slightly from one group to the next with the exception of those
with silicotic nodules.
Later, in 1956 KING, MAGUIRE and NAGELSCHMIDT
reported similar studies on a further series of 71 coalminers' lungs
from men who had worked in pits covering all the ranges in coal rank
found in South Wales.
In addition, 15 cases of silicosis from Cornish
tin mines were included.
Pathological and mineralogical analyses were
undertaken as before but on this occasion, for 3n of the cases, the
chest radiograph was compared to the level of pathology found at autopsy.
The results for the group of coalminers were similar to the earlier
study.
Whilo the total Ir.ng dust increased with increasing -pathology,
the quartz percentage did not change.
The authors therefore concluded
that quartz was not a significant factor in the development of
progressive massive fibi-osis and they favoured the idea that a
secondary factor, usually tuberculosis, was required in addition to dust
in order to produce this condition.
It was pointed out, however, that
the lungs of coalminers usually contained more quartz than tin miners
with pronounced silicosis and it was suggested that coal dust diluted
the quartz and therefore reduced its effect.
These studies were later enlarged to include the examination of
lungs from miners in the Cumberland coalfield (FAULDG, KING and
NAGELSCHMIDT, 1959) and the Lancashire coalfield (SPINK and
NAGELSCHMIDT, 1963).
In both areas it was found that the lung dust
from all grades of pnfMir.occnicr.is had a higher percentage quartz than
had been found in South Wales.
In these areas there was some evidence
of a progressive rise in the percentage quartz with increasing levels of
pathology although in Cumberland no cases were reported that the authors
recognised as classical coalworkers1 progressive massive fibrosis.
In
both areas, however, some men often classified as rock workers had a
very high percentage of quartz in their lung dust and lesions similar
to silicosis.
In some cases these silicotic nodules had fused to
produce what was termed "silicotic mssive fibrosis".
In 1963 NAGEI.SCHMIDT _e_t al_. specifically examined lungs from
cases of progressive massive fibrosis for evidence of the importance
of quartz in the development of these lesions.
They reported that
while the total dust content of PMF lesions was on average twice as
high as the rest of the lung tissue, the percentage quartz in the dust
of 32 cases of PMF was slightly higher than that of 58 cases of simple
pneumoconiosis but the difference was not significant.
It was
concluded that quartz had not been an important factor in the development of progressive massive fibrosis in the cases examined.
A
similar increase in the total content of quartz in PMF lesions was
observed by VYSKOCIL et_ al_. in
1970.
Studies relating the levels of pneumoconiosis in coalminers to the
varying dust parameters hove nov.f appeared from several countries.
In
the USA, NAEYE _et_ jvU (1971) and NAEYE (1972.) reported the results of
studies in which pneumoconiotic lesions from the lungs of miners
working with different ranks of coal were compared with the levels of
contained "silica crystals".
These were estimated by a counting
procedure using polarised light, and the authors admitted that their
They reported that the highest levels of "silica crystals" were
present in the lungs of men who had mined high rank coal and that
these men had the highest levels of pneunoconiosis.
In 197** SWEET et al.
published the results of a study in which they had examined the lungs of
a group of bituminous coal miners from the USA.
Pathology was compared
to detailed mineralogical analyses of the levels of coal, non-coal
minerals and quartz, but unfortunately only sections of the lung were
analysed and the mineral levels had to be expressed as grammes per
100 grammes of dried lung tissue.
It was found that both the levels
of coal dust and free silica increased with increasing levels of
pathology.
From Australia, GI.JCK _et_ _al_. (1972) reported that
pathological data were available from the lungs of over 700 coalminers.
They reported a 15-point classification scale for pneumoconiotic
lesions including four grades to cover nodules of silicotic type.
.
.5.
Unfortunately, no dust analyses had been undertaken and much of the
pat.hol orrionl data dealt wi tb emr.hvsema and chronic bronchitis. Ir.
1971 LEJTE3ITZ e_t_ nl_. reported detailed dust measurements from a
series of German coal mines and compared these with the number
cases of pneumoconi osis certified from each.
of
They found that
pneumoconiosis correlated well with the rank of coal mined, with the
highest rank producing the most cases.
The mine with the highest
quart?, content in its dust produced the fewest cases of pneunoconiosis.
However, in 1976, KONN et al. stated their view that coalworkers'
tmeumoconiosis was to be considered mainly as a type of silicosis, with
the level of disease and the type of histology being determined by the
quartz content of the inhaled dur.t.
GTBSON's original suggestion in 1B?3 that the larger lesions of
coalworkers' pneumoconiosis resulted from a tuberculous infection
superimposed on the original coal dust lesions has been re-examined
more recently.
In 19'*8 FLETCHER obtained positive cultures of
tuberculous bacilli from the lungs of 25 out of a group of 75 PMF
r•'?.".<?".
Tri 1°57 PIVF.Pfi et al . obtained pontitive cultures froin th^ lurrr-
or ° out of P° cases of H"F not diagnosed as tuberculosis during life.
In addition, however, the series of cases under study included J1 cases of
PMF with definite tuberculosis diagnosed clinically and histologically.
Tre exoCt ir.v.ort: nee cf VuV-o:^1.]"! our; nr ctV;c-:r : nfrc:' i -.-r\r- in the
devel orme-it of T'-'F is, however, still uncertain anri in 1°7- Hi'IDER
summarised the situation as follows:
"Whether advanced forms of
silico.sis ar.d Tj&.rticulnrly PMF is always accompanied bv the ccmbi.n&d
effects of silica and tubcrculor-is or vhether they can be ca.used by
silica alone has been the subject of much debate and a conclusive
answer to this question cannot yet be given".
As far back as 19(42, D'ARCY FAST and his co-workers demonstrated
that the early states of coalworkers1 pneumoconiosis produced a pattern
of fine reticulation on a radioe-ra-Dh and since that time the presence
of this reticulation has been recognised as indicating a level of
pneumoconiosis for which compensation may be awarded.
However, doubt
r^rainpd for some time as to exactly which aspects of the disease
resulted in the reticulation.
00110", JA'-'KS ard WF."TV.'GRTH in
19^9
summarised the situation at that date and suggested that both the
"granules" and "pinhead opacities" reported by other workers were due
to the presence of coal dust nodules.
They concluded that the degree
6.
of focal emphysema associated with the dust nodules could not be
accurately assessed by radiology but that a sharply defined net-like
appearance in radiographs corresponded with severe focal emphysema.
In 19^5 SUTHERLAND suggested that the radio opacity of coal dust
nodules alone would be insufficient to cause a pattern of reticulation
on radiographs without the contrasting effect of accompanying focal
emphysema.
However, GOUGH, JAKES and WENTV/ORTH were able to show
that nodules could be demonstrated by X-ray in the complete absence of
emphysema and concluded that the fibrous tissue of the nodules
contributed more to their radio opacity than the mineral content.
CAPLAN in 19&2 showed that for a group of coalminers from South Wales
the size and number of dust nodules correlated we]l with radiological
category.
He found that no cases of Category 0 and only 11$ of
Category 1 had fibrotic nodules.
were btyo and 77$ respectively.
The figures for Categories 2 and 3
It was reported that no case had large
numbers of fibrotic nodules but no dust analyses were undertaken so
that the effects of mineralogical content on radiographic
categories
could not be examined.
This problem was further considered in a series of studies by
RIVERS et_ al_. (1960);
ROSSITER et_ al. (1967);
CASSWELL et al. (1971)
and POSSITER (1972).
Initially, RIVERS e_t al. concluded that in
miners from South Wales the mineral content of inhaled dust contributed
weight for weight about nine times more to X-ray opacity than coal.
In lator papers, however, the authors renorted on a larger series of
lungs from a wider rcngc of coalfields and concluded that the
differential was only 3 • 1.
It was admitted, however, that much of
this anomaly was due to the exclusion of Categories 0 and 3 from the
earlier analyses.
In these later studies, good correlation between
dust and radiographic category was found in most* cases but two small subgroups gave anomalous results.
The first group consisted of lurr-r,
from Scottish miners who had a higher radiographic classification than
their dust content appeared to warrant but the authors concluded that
this was due to the inhalation of soot from naked flame lamps.
The
second sub-group consisted of cases with "nodular" sized opacities
which were again given a higher radiographic category than would have
been expected from their dust content.
In Germany, both EINBRODT (1965) and WORTH _et_ al. (1968) showed
that the racliographic category of coalworkers1 pneumoconiosis (silicosis)
7.
tended to increase with increasing total dust.
WORTH and hie
colleagues concluded, however, that the pneumoconiotic shadows were not
caused directly by the inhaled dust but by the fibrous tissue reaction.
NAEYE _e_t_ _aJL. (1972) reported on the lungs of 77 bituminous coal miners
and found that the correlation between radiographic categories and the
volume of pulmonary dust nodules was good.
They also indicated that
the lung content of silicon dioxide correlated well with the radiographic
category but, unfortunately, this material was estimated by a light
microscope counting process and not chemical analysis.
In 1970,
RYDER et al. published the results of a large study in which the lungs
of 2^7 coalminers had been examined and radiographic category was
compared not only to the levels of pneumoeoniosis present but also to
the levels of emphysema.
It was found that higher levels of
emphysema were present in those pneumoconiosis cases showing the finer
punctiform type of radiological change than in cases showing the
larger micro-nodular and nodular opacities.
This? study used the 195$
standard international classification of radiographs of pneumoconiosis
issued by the International Labour Office.
More information was
produced in 1'97'* when LYONS ejt al. reported the results of a new study
of 95 cases in which the revised ILO radiographic classification of 1968
was used.
This classification makes allowance for irregular opacities
nK well as rrmncipri nodular onfis nn<i the autho7"S reported that the nulnonnry
emphysema of coalworkcrs correlated better with the irregular radiographic
markings than with rounded opacities.
Tn 1953 the British National Coal Board commenced a l~rge
epide;niolo~icnl study involving all the men working in a series of 25
collieries.
The dust levels and chemical compositions of dust were
carefully recorded for a number of occupational groups in each colliery
and the period of time that each man had worked in any occupational
group v.'as also noted.
The men were examined at five-year intervals and
chest radiographs were taken.
Simple lung function studies were also
undertaken and complete medical histories recorded.
The aims of
Pneumoconiosis Field Research have been documented in a number of
publications which includes FAY and RAE (1959);
1
and JACOBS^
ROGAN e_t al. (1967)
et al. (1971).
In 1971 it was decided to obtain the lungs of as many men as
possible, who hnd taken part in these surveys, for pathological
examination and mineralogical analysis of lung dust.
The main aims of
8.
this study were a comparison of the type and profusion of pneumoconiotic
lesions with the lung dust content at autopsy and lifetime dust exnosure.
In addition it was proposed to compare the pneumoconiosis category of
chest radiographs obtained during life with the size and structure of
lung dust lesions and lung dust content.
Estimations of emphysema
present in each case were proposed with the extent of emphysema
estimated by a variety of methods including that published by HEARD
(1969) and the point counting method of DUNNILL (1962).
Apart from the
overall levels of emphysema, the different types of emphysema would be
estimated separately in addition to estimations of the number and size
ranges of individual areas of circumscribed or centriacinar
emphysema.
It was also proposed to estimate the extent of bronchial gland
enlargement and to correlate this with clinical evidence of chronic
bronchitis obtained during life.
The lung dust analyses were planned
to cover estimations of the mass of total lung dust, coal, ash, quartz,
kaolin and mica found in each set of lungs as well as the percentage of
each of these components present.
In addition it was hoped to analyse
the dust content of individual lesions separately to see if this
differed from the lung dust burden as a whole.
It was also proposed to
undertake particle size distributions of the lung dust from all cases.
The present report includes the results of conrnarrsons of total
lung dust content and its components, with the types of pneuinoconiotic
lesion present in the lung tissue as well as n comparison of crest radiographs with, lung pathology and dust content.
Results from the overall
estimation of enrphysema by the Brian Heard method are included but the
more detailed estimations and classification of emphysema as well as the
results from studies of bronchial plands and the histolofrical
classification of the individual pneumoconiotic lesions is not yet
complete and will form the basis of a subsequent report.
This report
will -?.]so include the results of the size distribution studies on lung
dust and the results of analysing the dust content of individual dust
lesions •
9.
2.
2.1
1-JATERIAL3
!:-..T:!ODG
Case collection
The majority of lungs examined in this study were supplied
by the Pneumoconiosis I'edicnl Panels.
Since most lunpjs
examined hy the Panels came from men with some level of
pneumoconiosis it had to be accented that the series v;ould not
be representative of the whole population of the PFR study.
In order that the Pneumoconiosis Medical Panels could identify
men who had taken part in the PFR study, each Regional Panel
office was supplied wit!) a complete list of index cards giving
the necessary personal details of all appropriate men from the
PFR colliery in their area.
All cases seen by the Panels were
checked against this list.
In an attempt to increase the number of lungs obtained from
men with little or no pneumoconiosis, hospital pathology
departments in some areas were approached and some agreed to
supply lunrrn from men who had worked in PI'"? collieries.
Artain ,
index cards or lists of names were supplied to aid case
recognition.
The material for the present study consisted of 500 sets
of lunr;s from a series collected consecutively between June 1972
and October 1977.
A number of cases vere rejected for reasons
indicated in Table 2.1.
Reason for exclusion
Number
Patholorist's report did not correspond with
lungs..
3
Lur.rs putrefied.
1
Previous lobectomy.
1
Subject absent from all PFR surveys.
1
Active TB inadecmatelv fixed on receipt.
2
TABLiC 2.1
Cases onitted from consecutive
series.
10.
Of the 500 cases 23 were obtained directly from hospitals, the
remaining 'i?7 coming from Pneumoconiosis Medical Panels.
In
the majority of cases the heart was also made available and these
were stored for later examination.
2.2
Pathological examination
Adequate assessment of the lesions of pneumoconiosis and
emphysema is dependent on the quality of material available for
examination.
For satisfactory
results the lungs should be
properly inflated and fixed in an inflated state.
The lungs
from the present series v;ere initially prepared at many
different laboratories throughout Britain and were not uniformly
satisfactory when finally examined in Edinburgh.
Thus, although
all lungs v/ere processed in the same way on arrival at the
Institute of Occupational Medicine, the amount of information
that it was possible to gather from each case did vary.
For examination in the present study, lungs were first
washed for 2k hrs to remove formalin and then sliced in the
sagittal plane at 1 cm intervals.
In most cases the lungs had
also been cut in some way at autopsy.
Slices were numbered for
identification from the periphery to the hilum.
A representative
slice was chosen from both right and left lungs (TIIURU3ECK, 19u?)
and all further measurements were made on this slice.
The outline and main lobar anatomy were traced onto paper
and lesions of progressive massive fibrosis and any sizeable hard
nodules were indicated on this drawing.
The slice was then
divided visually into six zones (Iii,ARD, 1969) each of v/hich was
subdivided into fifths and all measurements were made with
reference to these.
The dimensions of any FMF lesions v/ere
recorded and discrete dust foci counted.
For the purposes of
this study any dust deposition surrounded by non-dusted lung
tissue was regarded as a focus.
For a comparison between the
numbers of dust lesions found in the different cases no
distinction was made between sizes or types of dust foci although
future work will analyse such differences.
For most of the
analyses reported in the present study, however, the cases were
divided into three broad pathological types, M, F and PMF.
consisted of cases where discrete dust rtenooits were -present
M
11.
without any macroscopic evidence of fibrosis.
F cases were
those in which theT-o wore ono or more nodules with a solid,
palpable centre of nt least 1 mm and PHF cases contained at
least one lesion of 1 cm or more in addition to smaller
lesions.
Except where specifically stated, the PMF group, referred
to in the Results chapter of the present study, was derived from
these pathological examinations, since it was found that X-ray
recording of large opacities did not always correspond
»• J. ml
O J - v - | • i. ^ ^.'v, > . w '-
\J :
^ t .t
J. <-* t«i* < A
(.An
CAvXÔ^'-^T.
*
*_*-l
V*li<~
exactly
_
JJ14J. ^J»_/i_»Ô
of comparison FKF caaes were divided into three groups which
theoretically corresponded to radiographic categories A, B and
C.
These will be indicated in the script as Ap, Bp, Cp.
For studies of emphysema, only airspaces of 1 mm or more in
diameter were considered as enphysematous.
Emphysema was
assessed and recorded in two stages by the methods advocated by
HEARD (1969).
The first estimation simply noted the presence
or absence of emphysema, while the second was a visual estimate
of the proportion of a zone which was made up of ernnhysenatous
airspaces and was expressed in fifths of a zone or thirtieths of
a whole lump: slice.
For the remainder of this report, these
latter estimations are referred to as the Brian Heard count
number 2 or BH2 for short.
In addition to these estimations of lotal emphysema,
different anatomical types of emphysema were estimated separately.
Maximum airspace size was recorded for each type of emphysema and
the presence of bullae and honeycombing was also noted at this
starre.
Apart from the simple estimations of emphysema by the
Heard technique, levels of each type of emphysema have also been
estimated for all suitable cases by a r.oint counting r.etliod
(DUNNILL, 1962).
However, for the present report only the BH2
estimations of overall emphysema have been used.
Analyses using
the more detailed estimations will be included in a subsequent
report.
In the present study the BIis count in all zones was recorded
for both lungs in '*02 cases and for a single lung in a further 7'1
cases.
A complete count of dust foci was available for both
12.
lungs in 152 cases and for a single lung in 1W cs.ces.
Data
were examined statistically to determine whether counts recorded
for one lung were applicable to both.
No significant difference
was found between left and right lungs in respect of the BH2 or
counts of dust foci.
(To validate the assumptions necessary for
the testing of differences between mean values, the square root
transformation was uned.)
Thus, for the 3H2 estimation an
average count was used when estimates for both lungs were
available.
When only, one lung was used for a count of dust foci
the total count was estimated as twice that number.
For histological examination of the lungs, tissue blocks
were taken from each lung sone, from main, upper find lower lobe
bronchi and from a hilar lymph node.
These specimens were
embedded in paraffin wax before sectioning and staining for light
microscope examination.
Following pathological examination the lung slice was
photographed and when the material was suitable a Gough section
was made.
For the first 256 cases one slice of a lung was
retained for future study.
For the remaining cases a whole lung
was kept. The side from which material was retained was
determined by a randomisation procedure. This resulted in the
retention of material from 2'f? left lun;~3 and 253 rirht lungs.
Cn occasion randomisation was abandoned in favour of keeping
suitable material for further work.
All remaining tissue was made available for dust analysis.
2.3
Chest radiographs
Full-sized chest radiographs taken within four years of
death were available for 261 cases.
These were obtained either
from Pneuroconiosis Medical Panels or from hospitals, or were
taken during the periodic surveys which are part of the
Fneumoconiosis Field Research programme.
The films were
randomised and read in two separate groups by a panel of four
doctors from the National Coal Board's X-ray service.
A fifth
reader was present on the' first occasion but because he was
absent for the second reading session, no account has been taken
of his readings in the present report.
r
The production of nn
nvor.^fo ren<iin; fr>r fi'sch c.iso is HoscrihiH in A'-.por.djx C
13.
?..k
Smoking histories
The .smoking histories of the men in this study v/ore mainly
recorded os part of the Pneumoconiosis Field .Research study
investigations.
V/here the information was lacking from this
source it was obtained from the Pneumoconiosis Medical Panel
records.
Only a simple division of the cases into three groups
(smokers, ex-smokers and non-smokers) was used for this report.
The use of this dual source of information appeared justified
since where data were available from both sets of records on any
It
One
Wctta
JUUIIU
UJau
JJCJ.U
«o.b
JL u
between the two.
2.5
Dust analysis
Following pathological examination, either the right or the
left lung was used for dust estimation.
Approximately 97 per cent
of this lung was available in most, cases.
In the early stages of
this work material from both lungs was used for dust analysis.
Ten cases were found unsuitable for dust analysis as indicated in
Table 2.2.
<eason
Number
Figures for two lungs in same case not
comparable.
Original specimen of only one lung.
Ir.corrplete lungs without details of amount
missing.
TABLE 2.2
Cases rejected for dust analysis.
For analysis of the remaining, '*9^ cases lunjr tissue v/ns finely
sliced and allowed to drain pri.or to weirhin.p; and mincing.
The
minced lungs were dried in vacuo at 105 C and ground in an end
runner mill to give particles about 200 jjm in diameter.
dried ground lunsrs were weighed and stored until required.
The
The
procedure employed for the recovery of dust from representative
samples of the dried lung was a modification of the method reported
by i\IVL'i\o et al. (19^3) ifl which tissue is removed by hydrolysis.
with 11.''; f; h.vdrocMoric aci'! i>t ^0°C.
The dusts recovered from
the tissue digestion procedure were ashed to constant weight for
three days in a muffle furnace at 380 C and their coal content
calc'ilnted from the weight lose.
The quartz, kaolin nnd mica
content of the residual ashes v;ere determined by infrared
spec trophctomc try using the potassium bromide disc method
(DOiXiSON and îlYTHKVK, 1973).
Since, for most cases, a single lung was used for dust
analysis, corrections have been applied in calculating the dust
content of both lungs so that the different ventilation of the
right and left lungs could be taken into account (SVANBERG,
for calculating total weights of dust in both lungs should be
2.17 where the left lung was available and 1.85 where the
right lung was analysed.
For the series of lungs used in the present study the
average weights of dust found in the left and right lungs were
used to calculate similar factors.
The figures obtained were
2.16 and 1.P>6 respectively.
Since, however, these factors were based on figures from
one lung only in each case it was considered desirable to check
the calculations with, a small series of lunrs where both right
and left lunrs v:ere used for dust analysis.
Ten additional
sets of lungs, collected after the first five hundred, were
therefore analysed separately and the dust weights in left and
right lungs compared.
The correction factors derived from this
series were 2.2'* and 1.°1 for left and right lungs respectively.
There was some statistical significance attached to the
difference between these two sets of factors.
however, given
the degree of experimental accuracy, these figures were
regarded as sufficiently close to the averages for the whole
scries ard t.o Cvanberg 1 s calculation:; to justify the UKO of this
type of correction factor.
It was decided that the average
factors obtained from the present series (2.16
and 1.R6) were
the best to use for the purposes of the present report.
2.6
Methods used to derive estimations of exposure to mine dust
The working nopulation of each colliery included in the PFR
was divided into occupational groups related to the place of work
and particular occupation and dust exposure estimated for each
15.
group.
Shift average dust concentrations were determined for
each occupational group.
Individual dust exposures were
calculated from the numbers of shifts worked in different groups,
the shift time and the appropriate dust concentration
(DODGSGN _et al., 1971?
'..'ALTON et al., 1977).
Many men in the PFR were employed in the same colliery
prior to the start of the study in 1953, but others transferred
to PFR pits only after the commencement of the investigation.
In both types of case it was necessary to make an assessment of
previous duct exposure and this was attempted, making the
assumption that dust concentrations in PFP. pits just prior to
the study were similar to those recorded during the first ten
years of the project.
It was also assumed that the dust levels
in PFR pits would approximate to those found in other
collieries in the same geographical area.
Colliery occupations were classified into six working
categories and each man's period in any of these v/as recorded.
These categories v;cre as follows:Development in stone (hard heading)
Development in coal
Coalface (coal-getting shift)
Coalface (non-coal-getting shift)
Elsewhere underground
r- — e.—
•^ Mi I rai. r:
Approximate dust concentrations for each category were
calculated using the figures from occupational groups for which
dust measurements had been made and past dust exposures for
individual men were estimated by adding up their working periods
in each of the six categories.
Dust exposures were first
estimated on a yearly bnsir. and then expressed as grnm hours per
metre cubed (g.h.m."3) by multiplying by the factor 17'*0 which
was assumed to be the average number of hours worked each year.
-If..
3.
DESCRIPTION OF CASl-;3
Thin Autopsy Study, by virtue of its timing and main source of
material, was not expected to cover a random sample of the PFR
population.
However, it is of interest to compare the distribution of
important characteristics of the cases studied, with those that might
have been expected had the cases been a strictly random sample of the
miners included in the PFR surveys.
Tables 3.2 to 3.6 describe the
cases in this way, in relation to age, smoking habits, and radiological
state as determined by at least tv/o doctors after the radiological
surveys were completed.
For the purposes of this study it wan convenient to adont a
grouping of collieries.
It would have been possible to do this using
a number of different parameters including the percentage carbon or
percentage volatile content of the coal mined.
It was decided that a
suitable compromise would be to use the National Coal Board's rank
coding system (Table 3.1).
This coding system is based on a number
of calculations involving the burning characteristics of the coal.
resultant grading of collieries is therefore somewhat
The
arbitary.
However, this grading system differed in only a few instances from that
which would have been obtained using percentage carbon.
A satisfactory
»'j.Cji,ribu i_j-on o^ COCGC was achxGVGu by c«n.vi.G?Lrig tn£ CGJ__LJ.crj.cn j.n^c O?L/C
rank groups (Figure 3.-1).
This method of presentation highlights the
degree to which the cases were atypical of all miners involved in the
When expressed as a« percentage of the original PFR survey
populahion (Table 3.2) there was considerable variation between groups,
a larger percentage being obtained from the higher rank code groups.
Regional grouping has also been examined but does have the disadvantage
that M:%' of cases are concentrated, in the South V/ales area.
Firure 3.2
shows the age distribution of 500 study cases wMch ranged between 36
years and 85 years with 7S% of all cases falling between 61 and 80 years.
Clearly it is reasonable to exnect that the Autopsy Study cases would be
drawn from the older age groups of the original cohort.
Tables 3.3 a
and b confirm this supposition and show the age distribution by rank
grouping of cases at the time of the 2nd and 3rd PFR surveys together
with those that would have been expected if the sample had been random.
Tables 3.'4 a and b show figures for a similar exercise undertaken in
respect of sr.oking habit.
There appear to be fewer non-smokers and more
17.
smokers than would have been expected but these differences are of an
order which could have arisen by chance though the possibility remains
that they may be associated with effects of smoking on life expectancy
which are beyond the scope of this investigation.
Table 3-5 however
shows that the distribution of smoking habits with respect to age
among the cases was similar to that among miners at PFR collieries
generally.
To this extent therefore,the results reported below are
not biased because of the case-selection procedures adopted. •
For examination of PFR radiological state cases were divided into
t.i.
— . _
_. /•' -'-£j
-- J »>, J.111^^.
_.•....->. ^J i .... ..._•._•..
. . .1 1.1
iW ..
•
UJiAV-t-^l.*^WJ./fc-*»
,
J. (!£-,
progressive massive fibrosia (Tables 3.6 a and b).
At both surveys
for rank group the observed distribution of readings is very close to
the expected distribution while for other colliery groups there are
large discrepancies.
There are fewer Category 0 cases than would be
expected and more pneumoconiosis cases at all levels of severity.
Thus, for factors other than smoking category, the study group is
clearly biased in favour of the older and more severely diseased man.
In some interpretations this characteristic must be borne in mind.
18.
NCB
Coal
Rank
Code
o/
C/H
/tage
Carbon
C/0
Ratio
Ratio
C'/
Colliery
Rank
Group
W
1
101
94.0
135
20
4.0
6.0
E
1
102
92.7
66
24
1.8
9.6
H
2
201
92.4
58
23
1.3
11.5
F
2
202
91.9
51
22
1.3
1.5.0
I
2
204
91.4
46
20
0.8
21.0
V
3
301
90,6
35
19
1.0
23.0
T
3
301
89.7
?9
18
1.4
28.0
B
3
301
88.8
22
17
1.9
-
A
4
401
87.0
19
16
1.8
36.0
M
4
501
87.2
17
16
3.3
38.0
Y
4
502
86.3
17
16
2.3
38.0
N
4
502
85.6
15
15
3.6
38.0
X
4
502
85.2
12
15
4.0
38.0
R
5
602
84.6
13
15
3.9
K
5
602
84.7
13
16
6.3
38.0
i
i
Moisture
Capacity
Volatile
Content
-
0
5
602
85.4
13
16
5.9
37.0
L
5
602.
84.9
12
16
4.3
38.0
G
5
701
85.5
13
16
5.1
36.0
U
5
702
8.9
D
5
70?
_
i
i
I
84.6
11
16
84.0
11
15
8.9
84.1
11
16
7.3
39.0
i
Z
5
70?
P
6
802
84.1
10
16
9.0
38.0
c
s
6
802
81.8
8
15
9.5
41.0
6
802
81.9
8
15
10.2
40.0'
Q
6
902
81.1
7
16
15.2
39.0
j
6
902
82.5
8
16
12.7
4o.o
3.1
D e t a i l ? ; of the coal m i n e d at the collieries of the
rroeonioTis F i e l d R o r i e a r c h S t u ^ y .
This
l T i.eri e~ i n t o
to diviri-:; H>e
inform^' irn
Rank Group
Collieries
No. of Autopsy
Study Cases
% of PFR Phase 1
population
k^
?.1
H, F, I
120
. 2.7
3
V, T, B
1.15
1.5
k
A, hi, N, X, Y
90
0.8
5
K, 0, L, G, 1!, D, Z
7'»
0.6
6
P, C, S, Q, J
56
0.5
1
W. E
2
ABl.J:; 3»2
Autopsy stndy cases expressed as a percor.t.?.f:e of the
original PFR population divided by rank group.
20.
Pnnk Group
'
^r-^__
/: »'j
65+
TABLE 3.3
45
(a)
Hank Group
~~~~— -—_
MFC
i»S-''9
50- ^k
55-59 .
60-6'+
65+
TOTAL
TABLE 3.3
k
5
6
VTB
AKfiXY
KOLGUDZ
PCoOJ
(b)
0(24.4)
1(22.7)
2( 8.7) K 6.7)
5( 7.6) 2( 5.0)
8( 8.5) 3( 5.6)
23( 8.0) 19( 5.3)
23( 7.0) 17( ^.7)
11( 5.D 11( 2.8)
2( 4.9) 2( 3.2)
74
56
Age distribution at 2nd Survey of autopsy study cases
divided by rank.
2
HFI
o( 9.2)
0( 3.9)
5( 6.3)
?( 5-0)
8( 5.2.)
9( 5.0)
'9( 'u6)
7( 5.7)
^5
i 90
115
1 120
1
V.'S
"-—~__^_^
-3''
35-39
ko-kk
3
0(13.8) 7(^2.5) 4(44.2) 1(38.5)
5( 6.1) 6(12.8) 8(12.9) 4( 9.8)
8( 5.1) 10(11.6) 10(12.3) 6( 8.5)
9( 5.D 15(12.9) 25(12.2) 18( 9.2)
9( 5.D 28(11.9) 26(11.9) 20( 8.5)
?( 4.4) 24(11.3) 26( 0.4) 24( 7.3)
5( 2.7) 24( 8.6) 14( 6.3) 14( 4.7)
2( 2.6)
6( 8.3) 2( 5.8) 3( 3.5)
i
-3''
35-39
40-44
45-49
50-54
55-59
60-64
TOTAL
2
HFI
1
3
VTB
2(3?.i)
*»( 9.3)
k
AMNXY
r;
6
KOLGHDZ
PCSOJ
0(16.5)
3(33.1)
K 9.'0
5(12.8)
0( 7.5)
k( 9.7)
ov.'n.7;
_— \
10(12.V;
5( 8.7)
16(12.5)
31(12.8)
26(12.2)
16( 9.D
24(12.1)
22(11.3)
26(10.1)
32(17.9)
20(13.0)
20( 8.8)
2k( 7.3)
21( 9.2)
0( 5.9) K 5.3)
K 8.2) K 6.7)
5( 7.1) 2( 5.0)
6( 8.2) 2( 5.6)
18( 7.6) 17( 5.3)
21( 6.8) 19( 5.0)
17(10.3) 1H( 6. ^)
90
7k
7(12.'t)
* t . .
120
115
0(?0.7)
6(20.1)
56
Age distribution at 3"<i Survey of autopsy study cases
divided by rank.
Figures in brackets nre the numbers that would have been expected, if the
samnle had been random.
'1.
}j'::-.v G-r.-uv.
~~~^—--~___^^
1
WE
Smokinp; h^hit
2
HFI
N or, -S" ok or
6( 5.1) 12(16.3)
Ex-smoker
2(
23(23.6)
Unknown
14
TOTAL
45
TABLii; i*1*
s
I*
Ai::!XY
6
KOLGUDZ
FCSQJ
6( 9.D 6( 6.5)
4( 4.2) 4( 4.1) 2( 2.4)
5( 6.7)
76(70.0) 82(75.0) 60(55.3) 5K47.*) 35(34.1)
2.2)
Snoker
3
VTB
f
7d3. *0
4( 4.6)
6(10. '0
27
22
20
13
13
120
115
90
74
56
i>rocI1..: .13 habits oi' autopsy study casc-3 at tirce of
(a)
Sv.rvev.
1
WE
-—^ R a n k Group
— — ^________^
Smoking habit
2
HFI
3( 3.9) 9(10.7)
fc( 6.7)
5( 5.5)
1P(1P.3) i 43(4o.7)
20
63
Non-smoker'
Ex-smoker
Srroker
Unknown
h?o
TOTAL
T ' - R J S 3.^
i
3
VTB
AV1JXY
6
KOI.GUDZ
FC.SOJ
6( 7.3)
2( 5.D
4( 5.9)
4( 3.6)
10( 7.1)
5( 5.3) 4( 3.9)
55(52.7) 39(37.4) I V>(30.2) 2^(26.3)
i
i
•
! °o
115
56
5(10.2)
S;/:ckh^ habirs of autopr-y s:.^;dy --K:/U; at tiir.s of 3rd
ourvo;:.
in brackets pre the numbers that v:oulri have bên expected, if the
h.nd been r s r d n m .
——
(b)
Arre Groun
^ 3'+
Srrio'-tin'T bar) it "~-i
Non-srokers
o( 0.6)
Ex-snokers
0(
0.2)
Smokers
3(
2.2)
TOTAL
T.'lv. 5 3'1?
^
35_/«U
u
5-5^
55-64
65+
Total
o( 2.6)
10(10.8)
19(
21.2)
0(
0.2)
29
2.1)
10( 9.4)
21(
26.5)
0( 0.7)
32
19(15. '0 60(60.6) 132(127.7) 2( 1.1)
216
K
?0
Po
172
2
277
Comv.ari.son of rb.-.:.::•'-•«';. ar.d e::nactnd values for Einokinp; liabit
w i t h i n a,qe prouj:-s.
Expected va].ues p:iven in brackets.
1
Rank Group
~'Reading
,.
D
-
1
!
2
HFI
^
i
3
•
4
VTB
i
AF.NXY
i
5
: KOLGUDZ
6
;
PCSOJ
••i
j
i
i
!
•
c Mtegory 0 CWP 2 1 ( 2 4 . 1 ) 1 49(72.5) '•2(7°. 6) 20(61.5) ; ?3(5L5) ! 27(43.5)
i
i Simple CWP
PKF
23(14.5)
5( 2.0)
22( 6.0) ; 12( 3.D
14
TOTAL
45
(a)
i
-
V;E
otc--ory 0 C'vP 10(19.1)
s in-ole
CV/P
Unknown
o( 1.6)
,20
TOTAL
T.\ f3l,iO 3.6
45
(b)
j 14( 2.3)
1B( 1.4) ; 11( 0.6) : 5( 0.2)
i
s
22
18
120
1 115
90
HFT
3
VTB
22(4^.4)
35(59.9)
2
;
• 6( 4 . 3 ) ; 3?(1?.1)
PMF
34( 9.D | 23( 5.0)
26
1
'
i
i 17
10
74
: f-/?
i
i
;
i
Da flir tivr! r.'bliograr.hio c a t a ^ o r y cf autc:xsy s t i r i y cases
H:-r.:: 'J •.-.-,:};
.3 ; . .
39(10.3)
5( 5.0)
Unknown
T.1' OLE 3.6
i
3( 1.5)
L
;
:
;
AKNXY
5
KCIGrDZ .
6
P^SQJ
V:(61.2)
20(36.7)
' |0 (33.D
25( 8.4) 21( 8.5)
14( 2.9)
1S( 1.7)
6( 0.3)
2( 0.2)
11( 2.7)
14( 1.4)
! 63
44
40
34
21
120
J115
I J
90
74
[
' '
.T
D s f i n i r i v e rariioprar.hic cat~r?rory of autopsy sfcu-'ly cases
at 3rd Survey.
Figures in brockets are the numbers that would have been expected,if the
sample had been random.
I
12;
PMF
II M
r\j
W E
H
1
FIGURE 3.1.
F
-
I
V
T
B
A
M
N
X
Y
K
O
L
G
U
D
Z
P
C
S
Q
J
COLLIERY
COAL RANK GROUP
DISTRIBUTION OF AUTOPSY STUDY CASES BY COLLIERY AND PATHOLOGICAL TYPE
2k.
M
F
RMF
NUMBER
OF
CASES
36- 41- 46- 51- 56- 61- 66- 71- 76- 8140 45 50 55 60 65 70 75 80 85 AGE IN
FIGURE 3.2. DISTRIBUTION OF AUTOPSY STUDY CASES
Eff AGE AT DEATH SUBDIVIDED
THREE PATHOLOGY GROUPS.
INTO
wr-Aor
YEARS
25.
1*.
A COMPARISON OF PMEUMGGONIOSTS FOUND AT AUTOPSY
WITH LUNG DUST CCNTaiT ANU LIFETIME DUST EXPOSURE
The main aim of this section of the study was a comparison of the
different types of pneumoconiosis lesion present at autopsy with the
mass and composition of the lung dust and the lifetime dust exposures
of the men in question.
The main conclusions of this work are
summarised below and presented in full in the main body of the
chapter.
(a) For the whole group of cases the weights of all types of
variation from case to case. The mean weights, however,
increased as the type of pathological change became more
severe.
As an illustration the mean weights of total
dust for cases in the three pathological types were as
follows: M = 7.2 gms, F = 12.5 gms, PMF = 20.0
gms.
(b) When the collieries were divided into six groups depending
on the rank of the coal mined it was found that in cases
from all rank groups the mean lung weights of each mineral
increased between the three pathology types but the level
of increase varied considerably.
For cases with either
macules or fibrotic nodules the total dust content did not
differ significantly between the rank groups.
For cases
with PMF, however, those from the highest rank group (1)
coili.-ciiiir;i.i -î^TU3..Lj.cCIM»..1.y rrio~^ \iiiot. onsn ccioco Arcm G^J*CI* remit
groups.
(c) The mean coal content of lungs with soft dust macules only
did not vary between the different rank groups. Cases with
fibrotic nodules from rank groups 1-3
had a higher mean
coal content than those from groups k - 6.
For cases with
PMF, however, the"coal content decreased progressively between
rank groups 1 and 6.
(d) The mean weights of the non-coal components of lung dust
increased between the three pathological types for all rank
groups.
Within any one pathological type, the highest levels
were found in rank groups *t and 5«
(e) There were no significant, differences in the percentage coal
and mineral composition of lunp dust with differing types of
26.
pathology in the high rank collieries.
In low rank
groups, however, the percentage of coal decreased
between the pathological types M, F and PHF, and the
percentage of non-coal minerals was increased.
(f) Good exposure data were available for 119 men out of the
total of 500 and this subgroup was used to examine the
relationship between dust exposure and types of
pneumoconiotic lesion present in the lungs.
For the whole
group no obvious relationship was demonstrated.
No
between cases with fibrotic nodules and those with
progressive massive fibrosis within any single rank group.
For these analyses coal ranks 1 and 2 and ranks 5 and 6
were combined.
(g) The retention of dust components per unit exposure did not
differ between rank groups for cases with fibrotic nodules.
For PMF cases, however, it was found that the lowest
retention of non-coal minerals had occurred in collieries
mining the highest rank of coal (A).
The highest retention
of non-coal minerals and especially quartz was found in men
from the medium to low rank collieries (C).
(h) When the percentage composition of lung dust was compared
to that of the original mine dust it was found that there
was a higher proportion of the ash components quartz, and
kaolin and mica in cases of pathological type F or PMF from
low rank collieries but not from high.
4.1
Weights of dust in the lung and levels of pathology
The dust content of the lungs of 490'' conlworkers was
considered in relation to the levels of pneumoconiosis found at
autopsy.
For this purpose cases were divided into three types:
those with only soft dust foci or macules, those with hard
fibrotic nodules as well as macules, and those with the larger
lesions of progressive massive fibrosis.
The overall mean
weights of minerals and their ranges present in the lungs of the
men from each of the three pathological types is shown in
Figure 4.1.
This figure shows that while there is a considerable
.27.
spread of lung dust content in each group, the mean weights of
total dust and of each component measured in the lungs
increased from V: to F to FMF.
It would have been desirable
to compare the pathological levels and dust figures separately
for each of the 2^ collieries but in several of these too few
cases were available.
However, the mean lung dust weights for
men grouped by colliery in each of the three pathological types
are given in Table A.1 of Appendix A.
For analysis of the relationship between lung dust content
CXJIVjL
UI1C
|Jd t, 1LU J-Uf-, J.U a_L
UJ JJ<3 O
U -L
UUC: UU1VU ^11J.UO J. O ,
uliC
U \J JL. J_ X C JL J. CO
were split into six groups by coal rank (Table 3.1) or four
groups representing the main geographical areas of coal-mining
in Great Britain (see Table
A.*0.
Analyses were carried out in which the different mineral
components of the lung dust were considered relative to the
level of pathology for each of the six rank groups.
These
resxilts, expressed as histograms, are given in Figures ^.2 - 't.6.
The figures from which the histograms were derived together v/ith
the significance or non-significance for some important pairwise
comparisons of these data are shown in Tables A.2 and A.3 of
Appendix A,
Similar analyses based on geographical areas are
shown in Appendix A, Table A.^.
Figures *t.2 - ^.6 show that for
all rank groups, the lung weights of each mineral increased
bsiv.'eeii Liiy tiiree pulholoKi'Jcil iypas bul i~!!« levtsl of increase
varied considerably.
For cases with macules and fibrotic
nodules the total dust content did not differ significantly
between the rank groups (Figure ^.2).
For cases with PMF,
however, those from the highest rank group contained significantly
more dust than those cases from all other coal rank groups.
Figure *t.3 shows that the coal content of cases with macules alone
did not vary substantially between the different coal rank groups.
Cases with fibrotic nodules in rank groups '+, 5 and 6 had less
coal than cases from groups 1,2 and 3, while PMF cases showed a
progressive reduction in the coal content of their lung dust from
rank groups 1 to 6. The significantly greater total dust load
foxmd in PMF cases in coal rank group 1 seemed almost entirely
due to this high coal content.
The weight of the non-coal
component of the dust, together with its main constituents, quartz,
28.
kaolin and mica, was higher within any one pathological type
from collieries in coal rank groups 4 and 5 than in cases from
collieries in higher coal rank groups (Figures 4.4 -
4.6).
They also tended to be higher than in those cases from coal rank
group 6.
While collieries from South Wales and Kent mine
mainly high rank coal those from the Midlands and North Wales
produce coal of a lew rank.
Comparisons of pathological types
of pneumoconiosis with lung dust levels within these areas gave
results which corresponded quite closely with the extremes of
observations made for division by rank.
In other geographical
areas the distribution of collieries is such that useful
comparison with rank groups cannot be made.
In addition to the weight of any mineral present in the 490
cases examined, the amount of each mineral expressed as a
percentage of the total dust content was calculated for each
case and the results are given in Figures 4.7 - 4.10.
For coal
rank group 1 there appeared to be no difference in dust
composition from cases with differing levels of pathology but in
the other five rank areas there was a tendency for the proportion
of coal in the lung dust to decrease with increasing severity of
lung damage.
4-6
This trend was particularly marked in rank groups
(Figure 4.7).
A corresponding increase in the proportion
of non-coal mineral with increasing pathology and low coal rank
is shown in Figure 4.8.
Changes in the percentage content of
quartz and kaolin and mica closely followed the levels for
non-coal mineral taken as a whole (Figures 4.9 and 4.10). As
before, the figures on which Figures 4.7 - 4.10 were based,
together with the calculated significance levels for pairwise
comparisons of these data, are shown in Tables A.5 and A.6 of
Appendix A.
A similar exercise based on geographical areas is
shown in Table A.7 of Appendix A and again the differences
indicated between high and low rank groups are evident between
the South Wales and Kent and North Wales and Midlands groups.
4.2
Dust exposure during life and levels of pathology
and lung dust, content found at autopsy
The National Coal Board's Pneumoconiosis Field Research
includes estimates of lifetime dust exposure for all men at the
collieries involved and it is of interest in an examination of
29.
lung tissue to compare these figures with lung pathology and
lung dust content measured in the laboratory.
Many of the 4-90
men involved had died after long periods of retirement and
measured dust exposure figures were available for very short
periods of their working life.
It was decided therefore to
limit consideration of dust exposure, lung dust content and
pathology to men for whom measured dust exposure figures
covered at least 2($ of their working life and who had spent at
least 5C$> of their working life in the same PFR colliery.
r-r,nci rloyat i nn.^:
Y-pHnrprl
t.hp
4QO r?iKPS
to
11Q nnrt
these cases are given in Figures 4.11 and 4.12.
the
data
These
from
When these
cases were considered as one group, the type of pneumoconiosis
lesion present at autopsy showed little relationship to mean
dust exposure.
This was true both for total dust exposure as
well as exposure to the constituent minerals of the dust.
The relatively small number of cases available for
consideration made it unsatisfactory to use the original six rank
groupings in an attempt to see if these findings applied to all
coal-mining areas.
For these reasons the analyses illustrated
in Figure 4.12 use only four rank groupings, groups 1 and 2 and
groups 5 and 6 having been combined.
(To avoid confusion these
four rank groups are referred to as A, B, C and D.)
Similarly
with only ten cases falling within the pathological type M it
v.'ss net considered useful to subi'iwi'^'? th? B crrnun.
Thfii-p.fnTfi
only cases of the F and FnF pathological types were considered.
No significant differences in the mineral exposures were observed
between these two pathological classes within any single coal
rank group.
In addition to these comparisons of dust exposure and
pathology levels, the exposure figures for the group of 119 men
were also compared to their lung dust content.
Initially, the
weights of dust in the lungs of this subgroup were compared to
the dust levels found in the lungs of the whole group of 490 men.
These figures are shown in Table 4.1.
There were some
noticeable differences between the two groups.
With the
exception of coal rank group C, the mean weights of dust and its
constituent minerals in the cases with fibrotic nodules were
higher for the subgroup of 119 men than in the total group under
30.
study.
Furthermore, the PMF cases in this subgroup in coal
rank group D tended to have lower weights of minerals than were
found in the lungs of the whole population of ^90.
The sample
of 119 men with relatively good exposure data v/as, therefore,
not entirely representative of the whole series of cases under
study.
Mo obvious reason for this difference can be seen.
The average age of men in the two groups was very close (6?.^
yrs
and 65.2 yrs for the whole sample and the subgroup,
respectively.
r or trie auuî'uuu u
i
i'>c" .yi' v;iwai A c c . l i v e y f'joc
exposure figures were available, exposure data were compared to
lung dust content.
considered.
Each of the rrain dust components was also
These comparisons were made using linear regression
techniques applied to the data grouped by pathological type
assigned at autopsy, and coal rank area of origin (Table *f.2).
For the purposes of this report, the linear regression model
assumed was such that extrapolation of a case with zero recorded
dust exposure would imply zero dust in the lung.
The
considerations taken into account in selecting this formulation
are discussed in Appendix B.
For the '/.'hole group it was found that the relationship between
exposure and lung dust appeared to vary with the level of
pneumoconiosis, with PMF cases retaining more total dust, coal,
non-cop'.!. | quart", kar.iin and mica than nen with less s=«v«re 'J.ioC-^Sire
This is illustrated for total dust and quartz in Figures *+.13 and
"O^.
When the collieries were split into four rank groups,
however, a series of different trends was seen.
Cases with
fibrotic nodules appeared to retain a higher proportion of total
dust and coal in rank group A than in lower rank groups.
For
PMF cases there were no significant differences in the retention of
dust and coal between the four rank groups.
There was a tendency,
however, for PMF esses in group D to have retained less dust and
coal than cases in higher coal rank groups.
illustrated in Figures ^.15 and ^.16.
These findings are
The retention of non-coal minerals per unit exposure did not
vary significantly between coal rank groups for men with fibrotic
31.
nodules in their lungs, although men from group D tended to have
retained more of this material than men from other groups
(Table ^.2).
For.PMF cases, however, men from rank group D had
retained less non-coal mineral than cases from groups B and C.
Quartz followed a similar trend to non-coal mineral in men with
fibrotic nodules in their lungs but the increase in quartz
retention with decreasing coal rank was more marked.
Ken with
PMF in rank group A appeared to have the lowest retention of
quartz although the figures were not significantly different from
groups B nnd D.
Groui) C. however, showed higher retention of
quartz than any other rank group.
in Figures *t.17 and *+.l8.
These results are illustrated
The pattern of retention of kaolin
and mica between coal rank groups was similar to that of quartz
although the retention of these minerals in rank group D appeared
to have been particularly low in the PMF cases (Table
U.2).
Lung dust composition corn-pared with the composition
of mine dust
The composition of dust extracted from the lung tissue was
compared to the percentage composition of the dust to which each
of the 119 men was exposed and the results expressed as a ratio.
When the results from all the 119 cases were considered together
(Figure ^.19)
it was found that while there had been little change
in the proportion of coal in the lung dust as compared to mine
H\I.?+- for any of t.hfi pathol ogical types there was evidence of a
small increase in the overall percentage of r.cr.-coal minerals in
cases with PMF.
When quartz or kaolin and mica were considered
separately, however, it was found that both were present in
substantially larger proportions in lung dust than in the original
mine dusts and that the ratios increased ..between the three
pathological types (M to F to PMF).
For PMF cases the proportion
of these minerals in lung dust was 1.8 times higher than that
reported for mine dust.
For comparisons of the ratios of lung dust composition to that
of mine dur>t in the different rank groups the same four rank
groupings and two pathological types were used, on the reduced
group of 119 men as before.
The results of these analyses are
shown in Figure *4.20 and they indicate that for cases with
fibrotic nodules from the highest rank pits, there has been a small
32.
increase in percentage coal content coupled with a reduction in
percentage ash content.
There is no increase in percentage
coal in cases of FHF from the same pits and only a small
reduction in percentage ash.
Between the other three rank
groups, all cases, whether in the F or PMF group, show a
progressive reduction in the proportion of coal and an increase
in that of ash.
When quartz and kaolin and mica were considered
separately, cases with fibrotic nodules showed a small reduction
in the percentages of these minerals in lung dust as compared to
mine dust in the group of highest rank collieries.
In all
other instances, however, their proportions in lung dust were
well nôve those reported from thn collieries.
For esses with
fibrotic nodules, the highest ratios were found in rank group C
although the differences between the figures for groups C and D
are not significant.
For cases with PMF however, there was a
progressive increase in the ratio between lung dust and mine
dust through the rank groups A to D.
In PMF cases in the
lowest rank group the proportion of quartz, in the lung dust was
2.7 timer, higher than in the mine dust and the kaolin and mica
level was 2.k times higher.
In this connection, however, it must be pointed out that
while quartz and kaolin and mica, the only ash components
specifically estimated, comprised over 8($ of the total ash in
lung dust, they only made up about 65/0 of the ash content of mine
dust.
Thin difference showed some variation between rank groups
and is an indication that some ash component at present
unrecognised is being lost from the lung dust.
This is probably
occurring during life although it is not possible to be certain
that some is not being lost during dust extraction from the lungs.
The implications of this are dealt with in the Discussion.
The relationship between total lung dust levels and
dust composition in rmeumoconiosis cases
The lung dust studies already reported in this chapter
indicated that while many PMF cases from collieries mining the
highest rank of coal had high lung dust levels with a low ash
content in the dust, cases from low rank pits had lower levels of
dust which contained a much higher proportion of ash and its
components quartz and kaolin and mica.
Thi.'s evidence may suggest
33.
that there is a critical combination of mass and composition
for any individual at which severe pneumoconiosis is likely to
develop with the required mass reduced as the non-coal mineral
percentage rises in lung tissue.
In order to explore this
possibility more thoroughly, cases in the present study with
either PMF or fibrotic nodules were divided into three groups
with different ranges of total lung dust and their mean
percentage compositions of non-coal minerals were calculated.
These results are shown in Table ^.3-
For PMF cases there was
a significant gradation between the three groups, with cases
with less than 15 grammes of total lung dust having approximately
twice as high an average percentage of all the ash components as
those with more than 30 grammes of total dust.
The greatest
differences were seen with quartz, the low dust group having
approximately two and a half times more of this material in
proportional terms than the high dust group.
Cases with
fibrotic nodules when divided into similar groups by dust weights
showed no differences in non-coal composition below 30 grammes
of the total lung dust.
Above this figure, however, the mean
ash content of the lung dust was markedly less.
The dust mass differences seen between cases with high or
low ash content are probably due in part to differences in dust
exposure as indicated in Figure *t.12a where PMF cases from
collieries mining high rank coal appear to have been exposed to
more dust than those from collieries mining low rank coal.
Coal rank will haye had an effect on the composition of the dust
.deposited in the lung since high rank dusts have a low proportion
of non-coal minerals and low rank dusts have a much higher
proportion.
This compositional difference is, however, further
exaggerated by a selective accumulation of quartz and kaolin and
mica in men from low rank collieries.
Whatever the reasons for
these differences, PMF had developed in lungs with a very wide
range of dust mass and composition and the idea of a critical
mass and composition relationship seems the most likely explanation
of this fact.
Coal
Rank
Group
A (1 + 2)
B (3)
c (4)
D (5 + 6)
Pathological
Type
Number
of
Cases
Whole
SubSarrnle group
Weights of dust in both :.ungs (gms)
Coal
Dust
Subp;roun
Whole
Sample
Subpirour)
18.3
18.5
2.5
5.0
9.9
12.9
12.6
12.8
71
14
13.2
21.8
10.7
PMF
57
15
25.4
23.8
20.4
F
42
18
PMF
44
13
14.0
18.0
17.9
19.1
F
39
12
PMF
42
15
12.4
19.7
11.7
22.5
F
48
V?
11
11.0
14.2
11
15.8
11.6
Quartz
Whole i SubSample group
V/hole
'ianvnle
F
FMF
Non-coal
Kaolin
and Kica
whole
OUDSarnie EjrOUT)
Whole
Sajnple
Subp;roun
3.5
5.3
0.350
0.776
0.^69
0.821
3.87
2.68
3.75
4.1
5.^
5.0
6.3
0.688
0.927
0.877
1.200
2.93
3.66
3.43
4.45
6.0
1.187
1.694
1.150
1.672
4,22
6.12
3.93
6.30
1.250
1.411
3.49
6.00
4.77
4.63
6.1
5.7
10.3
12.4
6.2
9.4
5.6
6.6
7.1
5.**
7.1
0.939
^.7
9.2
6.9
I 1.654
10.1
1.80
;
TABLE 4.1
Weights of dust and its main constituents present in the lungs of the sample of 490 men and in the
subgroup of 109 coalminers for whom acceptable exposure records were available.
Pathological
Tvn«»
M
(i = 1)*
Coe.l Rank
Group
se
(an)
Slope
se ( a j j )
Slope
0.03^
0.015
0.060
0.010
0.066
A
2
0.026
0.030
0.026
0.037
0.025
0.014
3
1
0.0.37
0.022
0.019
0.065
0.026
0.069
O.C?1
0.045
0.089
if
0.048
O.C16
0.038
0.055
0.022
0.054
O.CC4
0.058
0.069
O.OC8
B (.1 = 2)
55
14
18
0.053
C (j = 3)
12
D (j = 10
overall
(j = D*
B (j = 2)
C
(j = 3)
B (j = 2)
C (j = . 3 )
D (j = 4)
*
Slope
0.011
A (j = D*
(i = 3)*
se ( a j j )
QUAKTZ
NON-COAL MINERAL
0.043
A (j = D*
PMF
Slope
COAL
10
overall
(i = 2)*
Cases
TOTAL DUST
overall
D (j = 4)
F
No. of
Model fitted:
se ( a j j )
KAOLIN + NIC A
Slope
se (a} , )
0.04?
0.013
0.020
0.017
0.141
0.019
o .085
0 023
0.052
0.025
0.041
0.021
0.115
0.034
0.127
0.033
0.060
0.012
0.056
0.020
0.040
0.014
0.005
0.052
0.004
0.007
0.067
0.006
O.D98
0.008
0.044
0.011
0.075
0.047
0.054
0.014
0.052
0.008
0.054
0.009
0.072
0.078
0.01^
0.039
O.OC7
0.010
0.019
0.012
0.035
0.014
0.045
0.008
0.077
0.014
0.070
0.014
11
0.052
0.0.10
0.041
0.016
0.063
0.008
0.091
0.013
0.068
0.009
54
15
13
15
11
0.060
O.CC4
0.004
0.068
0.005
0.006
0.061
0.010
0.015
0.011
0.012
0.080
0.015
0.062
0.007
0.009
0.077
0.076
0.037
0.073
0.110
0.008
o,.oo6
0.092
0.061
0.008
0.059
0.06?
0.058
0.058
0.063
0.058
0.007
0.014
0.120
0.013
0.045
0.013
0.037
0.021
0.053
0.010
0.127
0.085
0.017
0.057
0.013
O.C10
O.D30
0.014
0.019
Weight of dust component in both lungs = D E a., (dust exposure component)
i=U=1
where a,j = estimated constant if observation belongs to Pathology Grade i and Coal Rank Group j
= 0 otherwise
TABL5 ^.2-
The estimated slopes and standard errors for the relationships:
dust component = constant :c component exposure.
Pathological
Type' '
Non-coal Minera;.
Residual
Variation*
0-15 £ms
Lung dust veight
15-30 gms
30+ gms
F
% Ash
3'!3.0
36.7 d^2) ( ' )
37.0 (44)
20.1 (14)
PMF
% Ash
367.8
48.8
38.5
25.1 (27)
F
% Quartz
14.6
6.2
6.4
3.2
PMF
% Quartz
18.3
9.2
6.7
4.0
F
% Kaolin + Mica
152.9
24.5
25.1
14.1
PMF
% Kaolin + Mica
163.1
32.4
25.8
18.0
TABLE 4.3
(7V
(89)
A comparison of lung iust mass and the percentage composition of ash, quartz, kaolin
and mica in pneumoconLosis cases with either fibrotic nodules or PMF.
*
(t)
Calculated from a one-way analysis of variance on % non-coal, mineral within
each of the two pathology grades.
Number of cases..
37.
80
P.HIF.
70.
P.IV IF
60
WEIGHTS OF TOTAL
50
DUST, COAL AND
NON - COAL MINERAL
F
A1
F
IV1
40
IN BOTH LUNGS (gm)
30
P.M.F.
20
4
F
1
M
4
4 i
10
4
T
1
(
<(
I
o
4
••
—
TOTAL
DUST
COAL
NON - COAL
MINERAL
p.M.r.
20,
WEIGHTS OF QUARTZ
AND KAOLIN&MICA
10.
M
IN BOTH LUNGS (gm)
P.M.F.
M
ll
QUARTZ
KAOLIN &
MICA
FIG.4.1
MEAN WEIGHTS AND RANGES OF MINERALS PRESENT IN LUNGS IN EACH
PATHOLOGICAL TYPE
11
40
MACULES
NODULES
WEIGHT OF DUST
30
P. M.F.
IN
46
BOTH LUNGS
42
(gm)
20
44
21
8
28
42
SO
„ 39
19
29
19
10
18
27
11
I
3
4
COAL RANK GROUP .
FIG. 4.2
WEIGHTS OF DUST IN BOTH LUNGS IN RELATION TO PATHOLOGICAL TYPE
AND COAL RANK GROUP
40
11
MACULES
x&i
30
n
•Xnv
WEIGHT OF COAL
NODULES
IN
P.M.F.
BOTH LUNGS (gm)
20
46
44
r,o
21
42
rH
10
42
•#8
28
39
11
22
1
29
27
frt
3
2:
19
4
5
6
COAL RANK GROUP
FIG.4. 3
WEIGHTS
OF CO/.L
IN BOTH
LUNGS IN RELATION TO PATHOLOGICAL TYPE /! ND COAL RANK GROUP
19
MACULES
NODULES
28
P.M.F.
42
10
WEIGHT OF
NON-
19
COAL
MINERAL IN
39
BOTH
I!
44
45
LUNGS (gm )
1
29
14
5
19
42
50 >:
21
11
18
27
22
B
COAL
FIG.4.4
WEIGHTS OF NON - COAL MINtRAL IN BOTH
RANK
GROUP
LUNGS IN RELATION TO
PATHOLOGICAL TYPE AND COAL RANK GROUP
MACULES
NODULES
28
P.M.F.
42
WEIGHT OF QUARTZ
IN
19
39
BOTH LUNGS (gm)
44
11
46
42
14
+
50
18
21
11
19
27
22
1
2
3
4
5
6
COAL RANK GROUP
FIG.4.5 THE MEAN WEIGHTS OF G'JARTZ IN BOTH LUNGS IN RELATION TO PATHOLOGICAL
TCPE
AND COAL RANK GROUP
^y^
MACULES
NODULES
xWx
10 .
WEIGHT
P.M.F.
OF
KAOLIN & MICA
IN BOTH LUNGS (gm)
n)
28
T
42
T
*:¥:*
••ijifcx
5 .
11
39
i
46
m
19
I
42
::W§
-3-
21
22
27
3
ixfti;
14
rt-
5t
11
29
44
i
19
I
I
4
^
1
18
-:SS:
it
COAL RANK GROUP
FIG 4.6. WEIGHTS OF KAOLIN £ MICA IN BOTH LUNGS IN RELATION TO PATHOLOGICAL TYPE /ND COAL RANK GROUP
MACULES
NODULES
RM.F.
100 .
11
PERCENTAGE
75
COAL
11
22
ft
50
,J6
27
8
42
44
18
14
IN LUNG DUST
39
50 .
19
29
28
A
25.
I
19
^
i
COAL RANK GROUP
FIG4.7. PERCENTAGE COAL IN LUNG DUST IN RELATION TO PATHOLOGICAL TYPE AND. COAL RAflK GROUP
*
MACULES
NODULES
70 .
28
19 Mil
60.
42
39
50 PERCENTAGE
14
•9
NOW-COAL MINERAL
18
40
IN LUNG DUST
42
44
r1
30.
46
11
11
?2
20.
10.
21
i
i
!
1
^^
COAL RANK GROUP
FIG 4.8. PERCENTAGE NON-COAL MINERAL IN LUNG DUST IN RELATION TO PATHOLOGICAL TYPE AND COAL RANK GROUP
RM F
--
MACULES
NODULES
28
12 *
tm\
RM.F.
19
10
39
J
42
29
19
PERCENTAGE
14
QUARTZ
IN LUNG DUST
44
42^
6 .
46
11
11
18
27
50
21
22
2 J
I
3
4
COAL RANK GROUP
FIG4.9. PERCENTAGE QUARTZ IN I.UNG DUST IN RELATION PATHOLOGICAL TYPE AND COAL RANK SROUP
MACULES
NODULES
ixWxl
RM.E
50-
28
40 .
19
42
39
29
T
PERCENTAGE
30 .
19
14
KAOLIN £ MICA
IN LUNG DUST
42
44
18
11
20.
50
11
21
46
27
10.
COAL RANK GROUP
FIG 4.10.
PERCENTAGE KAOLIN AND MICA IN LUNG DUST IN RELATION TO PATHOLOGICAL TYPE AND COAL RANK GROUP
800-
RM.F.
750.
F
700.
650.
600.
P.M.F.
550 .
F
500.
450 .
M
t/\»
WOUIVL.
(gmhm" 3 )
4UU
35Q
300
250 .
^^
^
<i
P.M.F.
M
200 .
F
41
<>
M
<I
15.0.
100.
II
50 .
O
o
-L
DUST
COAL
NON-COAL
MINERAL
250-,
200.
175 .
_
150.
EXPOSURE
( gmhm" 3 )
P.M.F.
M
125 .
100 .
75 .
<I
50 .
f
(I
I1
RM.F.
25 .
Ill
QUARTZ
J
KAOLIN
&
MICA
FIG. 4.11
MEAN VALUES AND RANGES OF MINERAL EXPOSURES IN RELATION TO
PATHOLOGICAL TYPE
15
DUST
DUST
300 .
NODULES
15
P. M.F.
JWi
15
13
11
COAL
14
EXPOSURE
COAL
18
15
11
13
200
3
(gm h m" )
12
11
f,
100
1£2
3
A B C
4
3
5£6
D
A
B
4
5g6
C
D
COAL RANK
A
3
B
4
C
5&6
D
gi
GROUP
FIG 4.12(a). MINERAL EXPOSURES IN RELATION TO PATHOLOGICAL TYPE AND COAl
RANK GROUP
3
A B C
4
5S6
D
150 -
NON-COAL
NON-COAL
12
15
11
NODULES
P.M.E
11
100
18
15
fXPOSURE
13
14
KAOUIv & MICA
14
50
QUARTZ
KAOLIN & MICA
12
15
QUARTZ
11. U
1 &2 3
A B
4
C
5&6
D
1 &2
A
3
B
4
C
S&6
D
1 &2
A
4
C
5&6
D
1 &2
A
3
B
4
C
5&6
D
1&2 3-4
5&6
A
B
C
D
FIG 4.12 (b). MINERAL :XPOSURES IN RELATION TO PATHOLOGICAL TYPE AND COAL RANK GROU '
1&2
A
3
B
4 5£6
C
D
COAL RANK GROUP
55
•»
MACULES
O
NODULES
A
PMF
50
A
O
45.
WEIGHT OF DUST
IN
o
40
A A
O
35
BOTH LUNGS (gm)
MACULES
O
30.
25
20
15.
10.
5
1CC
200
300
400
500
600
700
800
-3,
DUST EXPOSURE (gm h rri
FIG. 4.13.
THE RELATIONSHIP BETWEEN THE DUST CONTENT OF THE LUNG AND DUST EXPOSURE
FOR CASES OF THE THREE PATHOLOGICAL T Y P E S
,p MACULES
3 NODULES
A
P. M.F.
4_
WEIGHT
OF QUARTZ
IN
3_
BOTH LUNGS ( gm j
vD
A
2 .
1 -
10
15
20
25
30
35
QUARTZ EXPOSURE ( g m h m ~ 3 )
FIG.4.14
THE RELATION BETWEEN THE QUARTZ
EXPOSURE FOR CASES
CONTENT OF THE LUNG AND <)UARTZ
OF THE THREE
PATHOLOGICAL TYPES
40
50
_
A
COAL R \NK GROUP A
V
COAL R \NKGROUP B
COAL RANK GROUP C
COAL RANK GROUP D
40
j
30
J
WEIGHT OF DUST
IN BOTH
LUNGS
(gm)
20 J
10 J
100
DUST EXPOSURE
FIG. 4.15
(gm h nf
)
THE RELATIONSHIP BETWEEN H4E DUST CONTENT OF THE LUNG'AND DUST EXPOSURE FOR CASES WITH FIBROTIC NODULES IN THE FOUR RANK GROUPS
50 _
m
COAL RANK GROUP A
$
COAL RANK GROUP B
©
COAL RANK GROUP C
Ei
COAL RANK GROUP D
40 .
WEIGHT
OF OUST
30 .
IN BOTH
LUNGS (gm)
20 .
10 .
103
300
DUST
FIG. 4.16
500
400
EXPOSURE
600
700
800
-3,
(gm h m )
THE RELATK3NSHIP BETWEEN THE OUST CONfENT OF THE LUNG AND DUST EXPOSURE FOR CASES WITH P.M.F. LESIONS II THE FOUR RANK GROUPS.
COAL RANK GROUP A
COAL RANK GROUP B
COAL RANK GROUP C
COAL RANK GROUP D
WEIGHT OF QUARTZ
IN BOTH
LUNGS
gm
10
QUARTZ
FIG. 4.17
THE RELATIONSHIP BETWEEN THE
FOR CASES
r
20
15
25
EXPOSURE gmhm"
QUARTZ CONTENT
WITH FIBROTIC NODULES
IN THE FOUR
OF THE LUNGS AND CUARTZ EXPOSURE
COAL
RANK
GROUFS
30
A
COAL RANK GROUP A
4
COAL RAf> K GROUP B
•
COAL RANK GROUP C
•
COAL RAT K GROUP D
WEIGHT OF QUARTZ
IN BOTH
LUNGS
(gm)
30
QUARTZ EXPOSURE
FIG. 4.18.
(gm h m
)
THE RELATIONSHIP BETWEEN THE QUARTZ CONTENT OF THE LUNGS AND QUARTZ EXPOSURE FO ? CASES WITH P.NIF. LESIONS
IN THE FOUR COAL RANK GROUPS
NIACULES
10
CASES
NODULES
55
CASES
P.M.F.
54
CASES
2.0
RATIO
I % IN LUNG DUST/
% IN MINE DUST)
..
COAL
NOIN-COAL
QUARTZ
RATIO UNITY
KAOLIN & MICA
FIG 4.19. A COMPARISON OF THE RELATIONSHIP OF THE TYPE OF PNEUMOCONIOSIS TO THE RE -ATIVE
COMPOSITION OF LUMG DUST AND MINE DUST EXPRESSED AS A RATIO
NODULES
PM.f.
2 .
COAL
ASH
COAL
ASH
RATIO
11
(% IN LUNG DUST/
15
% IN MINE DUST )
14
15
RATIO UNITY
15
14
_L
1&2
3
4
5&6
3
5&6
1&2
3
4,
5&6
1&2
4
5&6
A
B
C
D
B
D
A
B
C
D
A
C
D
COAL
FIG 4.20. (a).
RANK GROUP
THE RELATIVE COMPOSITIONS OF LUNG DUST AND MINE DUST EXPRESSED AS A RA- IO
IN RELATION TO THE TYPE OF PNEUMOCONIOSIS AND COAL RANK GROUP
QUARTZ
3
NODULES
11
.
KAOLIN & MICA
11
PMf.
15
QUARTZ
15
12
RATIO
(% IN LUNG DUST/
%IN MINE DUST }
KAOLIN & MICA
2
12
11
13
13
18
11
18
15
15
1 .
14
RATIO UNITY
14.
f
1&2
3
4
5&6
1&2
3
4
5&6
1&2
3
4
S&6
A
B
C
D
A
B
C
D
A
B
C
D
C3AL
FIG.4.20 (b)
RANK
1&2
A
3
B
4
C
GROUP
THE RELATIVE COMPOSITIONS OF LUNG DUST AND MINE DUST EXPRESSED AS A RATIO
IN RELATION TO THE TYPE OF PNEUMOCONIOSIS
AND
COAL RANK GROUP
5&6
D
59.
5.
A COMPARISON BETV.'EEM LUNG PATI-1CI.OGY FOUND A'].' AUTOPSY
ADI) CKEGT RADIOGRAPHS OBTAIHI-Ji) PUKING LII-'E
The main aims of this section of the study were to compare the
pneumoconiosis categories of chest radiographs obtained during life
with the structure and number of dust lesions found at autopsy and the
mass and composition of the lung dust.
The main conclusions of this
work are summarised below and presented in full in the main body of
the chapter.
(a)
A comparison of radiograrhic profusion of small rounded opacities
and pathological type showed thai uj° <->i uaaea wil'u only t>oil
dust macules were categorised as 0/0.
32% of cases with
fibrotic nodules were also categorised as
(b)
0/0.
Counts of total dust foci tended to increase with increasing
radiographic profusion of small rounded opacities, the overall
correlation being
(c)
0.^3.
The correlation between radiographic classification and
pathological findings in PMF cases was extremely good for the
large category C opacities but less exact for category B
opacities.
For the small category A opacities there was
considerable variation among the '+ readers used and 21 out of 37
cases with lesions between 1-5
cms observed pathologically were
not recorded radiographically by any reader.
(d)
WitVi S n.rjTpasi ncr rani ogfa^hi r nrnfiiRi on nf small rnnnded nnarH ti es
there was a significant increase in lung dust content and itc
components for cases with simple pneumoconiosis.
However,
cases with category 2 or 3 simple pneumoconiosis had higher dust
levels than cases with category Ap or Bp PMF.
(e)
The lung dust from cases classified radiographically as category
0 for small rounded opacitie.3 contained a significantly higher
proportion of coal and a lower proportion of ash than category 1
cases.
No compositional changes were found between categories
1, 2, 3 and PMFp.
(f)
No significant relationship was found between the radiographic
profusion of small rounded opacities and degree of emphysema.
However, for small irregular opacities there was a significant
increase between categories 0/0 and 0/1.
6o.
(g) Cases with p type of small rounded opacity were more frequently
associated with emphysema, had a higher mean count of total
dust foci and had higher levels of lung dust than cases with q
or r type opacities.
The proportion of coal in lung dust
decreased and that of ash increased progressively between cases
with the p, q and r types of small rounded opacity.
5.1
Data collection and handling
Chest radiographs are the only diagnostic technique used in
the recognition and classification of coalworkers1
pneumoconiosis
during life and it is of great importance to compare the findings
obtained from radiographs taken within a few years of death with
the type and severity of pathology and the lung dust content
found at autopsy.
In the present study it was possible to obtain 261
radiographs taken within four years of death from the total group
of 500 men.
Figures 5»1 and 5«2 show how these cases relate to
the whole group in terms of distribution according to the
colliery/coal rank and to the age and pathological type of the
men respectively.
In terms of the percentage of cases obtained
from coal rank areas and of age and pathological type the cases
with radiographs would seem to be an acceptable sample of the
total group.
The 261 radiographs were read by a panel of four doctors
from the National Coal Board's periodic X-ray service (PXR) over
two reading sessions.
In some cases considerable inter-observer
variation in classification occurred.
An average classification
was produced from those given by all four readers and this has
been used for the purposes of the present ..report.
It will be
appreciated that this approach to the analysis obscures what may
be important film-reader-dependent differences in apparent
relationships between pathological results and radiological
classifications.
We intend to explore the implications of any
such differences as part of the continuing work with these data
(by comparing results derived from each reader's separate
classifications).
In the meantime, the findings are presented
now in terms of "average" radiological assessments, with the
caveat that the reliability of these averages, and conclusions
61.
based on them, must be judged in the light of the variability
summarised in Appendix C.
The radiographs used in this study were classified
according to the 1968 ILO classification for small rounded
opacities and the 1971 ILO classification for small irregular
opacities.
This allows for 12 grades for the profusion of
small rounded and small irregular opacities which are further
sub-divided according to type.
Small rounded opacities are
graded p, q or r and small irregular opacities as s, t ur u.
Areao of FI-iF art: fjraueu M, a or ^ according io size.
necause
of discrepancies between the average radiogranhic readings and
pathological grading of PMF (which are discussed in Section 5)
it was decided that where it was necessary to separate PMF
cases from the rest this should be done on pathological rather
than radiographic grounds.
In the present study the results from each type of
radiographic classification were compared to the pathological
data obtained from lung examination and to the lung dust
content.
5.2
Radiographic category and pathological type
The radiographic categories for the profusion of both small
rounded and small irregular opacities were compared with the
tvnes of
pnfinmofinniOR}S
1 fisi on
fniinri
in
t.hft 1nnjr.«? arir) t.Vip
a
results arc chov/n in Tables 5«1 nd 5.2.
The same pathological
types were used as described in Chapter 3.
It is evident from these tables that more than 8O# of cases
containing only soft macules are recorded as category 0/0 for
both small rounded and small irregular opacities.
Cases graded
as F span a much-greater range of radiographic category.
Even
so 32% are recorded as category 0/0 for small rounded opacities
and 72% for small irregular opacities.
Modified exposure
techniques are often used when taking chest radiographs of men
known to have PMF. The result of this is a modification of the
radiological appearance of the lung tissue away from the PMF
lesions.
For this reason the background radiographic
classifications in cases of PMF may be misleading and are not
used in this renort.
62.
The data from Tables 5.1 and 5.2 are re-expressed in
Tables 5.3 and 5.^, with the cases sub-divided into the six
colliery rank groups used previously.
Initial investigation
shows that there arc no significant differences between the
colliery groups in the proportion of cases from each pathological
type that have been given any particular level of radiographic
classification.
However, the number of cases is too few to
draw any definite conclusions.
Radiogra-phic category and number of dust foci present
in the_ lun.p; tissue
Of the 261 cases for whom radiographic readings were
available 155 had counts of total dust foci, the remainder being
unsuitable specimens for counting.
The distribution of counts
for these cases is given in Table 5.5-
For convenience, and
because of the small numbers involved in some ranges, further
tabulations involving these counts have been reduced to' three
ranges 0-1^9, 150-299 and 300+.
Tables 5.6 and 5.7 show the
distribution of cases according to counts of total dust foci and
radiographic reading for small rounded and small irregular
opacities respectively.
Figure 5.3 illustrates the
distribution for small rounded opacities.
There is an overall correlation of 0.'-i3 between radiographic
category for small rounded opacities and counts of total foci in
r:cn-?KF 'jases.
This increase in rauioj^rapiiit; cieisi&if iua.!.iu.ri willi
increasing counts is influenced totally by cases assigned to
ft
pathological type F there being no significant correlation within
pathological type M.
No similar trend has been established for
small irregular opacities.
Of the category 0 cases 10 out of ^5 have already reached
more than 300 dust foci which may indicate that the number of
dust foci in the lung is determined at an early stage of dust
inhalation.
Cases with PMF more frequently appear in the 150-
JOO dust foci group but this is probably because the PMF lesions
have reduced the areas of lung tissue in which smaller dust
lesions can be present.
A similar comparison of numbers of dust foci and the
profusion of small irregular opacities is given in Tables 5.7
but in this instance the number of cases recorded as category 1
63.
or over is so small that no comparisons can he made.
5.^
A comparison of the types of radiograpMc onacity
and patholorical type
A comparison of the types of small rounded opacities
observed radiographically and the pathological type of the same
cases found at autopsy is shown in Table 5-8*
Cases listed as
uncategorised are those in which an average could not be produced
from the individual readings available (see Appendix C, p.1^7).
It can be seen that almost none of the cases classified as p, q
or r nave onj.y soit macules in their lungw ami i/nis its in
keeping with the hypothesis that it is rare for soft dust macules
to produce any type of radiographic opacity.
However, while
approximately half the cases recorded as p or q show the presence
of PHF, 12 out of 1*t cases of r type opacities were associated
with this severe level of pathology.
The information in Table 5«8 is re-expressed in Table 5-9
with the cases divided into the six colliery rank groups.
two rank groups AXYNX and KOLGUDZ appear to have a higher
The •
proportion of cases recorded as q in the F pathological type than
the other rank groups.
The reduction in the number of category
0/0 cancc in come coal rank groups is due to the fact that a
higher proportion of severe cases of pneumoconiosis was obtained
from some areas than others (see Table 3.6 (a) and (b) ).
A
comparison of pstiiological typ'e'«nd cases withriil'.t'erenttypes or
small irregular opacities was not attempted as almost all had
been graded as t type opacities.
5.5
Type of radjographic oracity and number of dust foci
present in the lungs
The relationship between the type of small rounded opacity
and the number of dust foci present in the lung is shown in
Tables 5.10 and 5.11.
These refer to all cases and to non-FMF
cases respectively.
In both series the majority of cases with p type opacities
have more than 300 dust foci although proportionately fewer cases
with q lesions reach this figure.
In the whole series the
majority of cases with r type opacities have between 150 and 300 •
dust foci.
All but two of these cases also have FMF and, as
demonstrated in Table 5.6, PKF cases are more frequently found
in this dust foci group.
5•6
A comparison of the r*athological and radioprnphic_
diagnosis of iirorrensive massive fibrosis (PKF)
A comparison of the pathologists1 and radiologists' grading
of PHF lesions is shown in Table 5.12.
Although the same size
tradings, A, B and C were used, results are not strictly
comparable because for pathological examination lungs were
sliced in a sagittal plane while X-rays were taken in the
From this table it is apparent that in the present series of
lungs ^9 cases of PMF recorded at autopsy were not recorded
radiographically.
Of these, the 11 cases recorded as Bp and the
one case recorded as Cp were read as a large opacity by at least
one reader but the use of an average score masked this finding.
Similarly, of the 37 Ap's 16 were read as a large opacity by one
or more readers and of the remaining 21 cases 12 had unilateral
PMF which was either borderline in size, oddly-shaped or a
cavitated mass frequently located adjacent to a fissure.
In the
9 cases which showed PMF in both lungs the above findings were
apparent in various combinations-
From these results at appears
likely that the radiological appearance of PMF is obscured if the
mass has an odd shape or shows central liquefaction.
Why the
•crecence of a ?HF lesion adjacent to a. fii=i;urtt should i.nask. ils
radiological recognition is not clear. A small number of
lesions (6) were classified as category A or B PMF radiographically
when pathological examination of the lung showed that the masses
concerned were either neoplastic or of other types of pathology
not related to the presence of coal dust. ' It was only with
category C PMF therefore that there was complete agreement between
radiologists and pathologists.
It must be emphasised, however,
that the readings used for this comparison were the average
gradings of four readers.
In most cases at least one reader
agreed with the pathological classification.
Tables 5.1J a - d
present the radiographic grading of large opacities for individual
readers.
For the purposes of the present report these are not
further discussed.
65.
5.7
Radiographic category and Inn/7: dust content
For the comparison of radiographic category and lung dust
content it was decided to combine the sub-categories into the
main radiographic categories 0, 1, 2 and 3 since the number of
cases with the higher gradings was so small.
PMF cases were
treated as three separate groups, according to lesion size.
Only small rounded opacities were considered as all cases with
small irregular opacities fell into categories 0 or 1.
The
mean values for total dust and its composition for each of the
main radiographic categories is shown in Table 5-11*-
The
relationship between total dust and radiographic category for
cases of simple pneumoconiosis is illustrated in Figure
5.^.
For cases of simple pneumoconiosis there is a significant
increase in lung dust content and its components with increasing
radiographic category (correlation coefficient 0.5*0.
However
the figures for PKF cases falling within Ap and Bp size ranges
are lower than those for categories ?. and 3 for dust mass although
PMF cases show no overall differences from categories 2 and 3 as
far as dust composition is concerned.
There is a clear gradation
between categories 0, 1 and PMF for all dust components considered
by mass and there is a difference between categories 0 and 1 when
the components are expressed as a percentage of the total.
There is no significant difference in mean dust composition
between the '-41 cases graded as category 1 and the 1'i5 CGSGG with
PMF.
These results are re-examined in Table 5.^5 with the cases
divided into the six colliery rank groups.
Because of the small
number of cases in categories 2 and 3 these have been omitted.
5.8
A comparison of the type of radiographic .opacity
and lung dust content
In order to determine whether any differences existed between
cases with and without the three types of small rounded opacities
(p, q and r) in terms of total lung dust and its composition, the
mean values of these were calculated for each of the four groups.
PMF cases were excluded.
in Table
The results of this analysis are shown
5.16.
This tabulation suggests tVmt cases without opacities have
the smallest mean total dust of any group and cases with p type
nodules have the most.
Cases with q or r type nodules have, on
66.
average, less total dust and coal than those graded p.
There
is little difference in total ash, quartz, kaolin and mica in
the three groups although all contain more than cases without
opacities.
Cases graded p find those without opacities show
little difference in the percentage composition of dust hut
there is a decrease in the percentage of coal between cases
graded p and those graded q and r and a corresponding increase
in the percentage of ash, quartz, kaolin and mica.
5.9
A comparison of radiocranhic category and levels of
ernphy sema nresent in the lungs
As a first step in exploring the relationship between radiographic classification ond the amount of emphysema, the mean
Brian Heard Count 2, the range of the Brian Heard Count 2 and the
percentage of cases without recognisable emphysema (BH Count 2 of
< 1/30)
were calculated for each radiographic category.
Tables
5.1? and 5.19 show the results for small rounded and small
irregular opacities.
No significant relationship is evident
between radiorcraphic category for small rounded opacities and the
extent of emphysema (Table 5-1$) •
For small irregular opacities
there was a significant increase in the amount of emphysema betv/een
0/0 and 0/1 (Table 5.20).
There were too few cases in the higher
categories of small irregular opacities to allow accurate
comparisons at. these levels.
5.19
it is noticeable that the mean BH2 counts for cases with small
irregular opacities tend to be higher for any radiographic
category
than for the corresponding category of small rounded opacity.
This is further illustrated in Table 5.21 where the mean emphysema
levels for cases showing only small rounded opacities are compared
with, those having small irregular opacities and those showing the
two together.
The mean emphysema levels for cases with irregular
opacities
are higher than the rest but some cases in this group still have
no recognisable emphysema at autopsy.
Those findings
illustrate
that cases with small irregular opacities either alone or in
combination are more likely to show emphysema than those with small
rounded opacities alone.
67.
5.10
Tyner. of raoj orranhic opacity nr.d levels of emphysema
Levels of emphysema for the 131 cases with types of small
rounded opacity recorded are shown in Table
5.22.
From this tab]e it appears that cases graded p are more
frequently associated with emphysema than are those graded q and
r.
In the whole series forty-three per cent of cases with p
type opacities have more than 5/30
of their lung tissue involved
in emphysema compared with twenty-four per cent and_ fourteen per
cent for q and r opacities respectively.
Similarly, very few
opacities graded p have minimal emphysema whereas the percentage
of q and r type cases with minimal emphysema is quite high.
This trend is still annarent when the mean BHj estimations are
considered for each type of radionraphic opacity.
V.'hen cases
without PHF were examined thirty-four per cent of those with p
type opacitievS and seventeen per cent of those graded q showed
more than 5/30
lur.r; tissue involvement in emphysema.
Only two
non-PMF cases shov;ed r type opacities and data were therefore
insufficient
for further comment.
V.'ithin the time scale of this
report it was not possible to test these observations
statistically.
In the present study it was not possible to compare levels
of emphysema with the different types of small irregular opacity,
s, t and u, since almost all irregular opacities were graded t.
68.
0/0
0/1
1/0
1/1
1/2
f\ / ft
83.3*
7.1#
9.5*
-
<-/ *
***
2/2
3/3
»
-
TOTAL
1CX#
2/3
3/2
TABLE 5.1
PMF
F
M
(35)
(3)
CO
(42)
32. 4#
17.66
15. 7#
7.8JS
12.7*
1
if
•>•»?/»
(33)
(18)
(16)
(8)
(13)
f f~ \
^î
2.9^
(3)
2.9,*
(3)
3.¥
3.^
2.9/o
-
(3)
-
10C$
(102)
14.5#
(17)
18.8#
(22)
20.5?»
(24)
15.^
(18)
15.^
(18)
•~* »-**''
1 • l.a
/ ^ \
\ 7/
(4)
(4)
0.8^
(1)
100J<
(117)
Small rounded opacities.
% distribution
of M, F and PMF cases over the radioftraphic
scale.
Absolute numbers in brackets.
M
PMF
F
(34)
(6)
71. 6#
16. 7#
(73)
(17)
41. 0^
24. 8#
(48)
(29)
0/1
80.9?^
14.3?;;
1/0
2 . 4?~
(1 )
7,ÔBi
(k~)
1 7 .QR<
(21)
1/1
I.e.'
2 • *VO
f M\
( 1 J
I.*?/*
(4)
(4)
9.4^
3.4$;
2.6?^
0.8#
1
-
(11)
(4)
(3)
(1)
0/0
1/2
-
3.9^
2/1
-
2/2
-
2/3
-
3/2
-
3/3
3/4
-
_
_
_
—
—
TOTAL
TABLE
100?.; (42)
100^
(102)
100?^
(117)
irregular opacities. % distribution
of M. F and PMF cases over the radiop;raphic
scale.
69.
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71.
Counts of dust foci
K
F
PMF
Total
0-^9
5
2
1
8
50 - 99
3
6
T
10
100 - 1^9
3
»
5
16
150 - 199
5
7
9
21
200 - 2'*9
3
7
8
18
250 - 299
3
6
15
2h
300 - 3a9
2
8
9
19
350 - 399
0
10
5
15
400 - ^9
2
6
3
11
-1
•zy
i
c
0
5
3
8
den
_ /inn
500 4-
TARLE 5.5
Distribution of counts of dust foci for three
pathological types.
72.
0/0
0/1
1/0
1/1
1/2
2/1
2/2
2/3
3/2
3/3
3/4
P.M.F.
< 150
150 - 299
300 +
DUST FOCI
DUST FOCI
DUST FOCI
37.8$ ( 17)
42.9$ ( 6)
7.7$ ( D
20$ ( 1)
11.195 ( D
20$ ( 1)
.
-
to .0# (18)
42.9$ ( 6)
30.8$ ( 4)
-
22.2$ (10)
100$ (45)
14.2$ ( 2)
100$ ( 14)
61.5$ ( 8)
80$ ( 4)
100$ ( 13)
22.2$ ( 2)
66.7$ ( 6)
60% ( 3)
100$ ( 9)
11.7$ ( 7)
( 1)
20$
-
100$ ( 5)
100$ ( 5)
100$
( 1)
100$ ( 1)
100$
( 2)
100$ ( 2)
100$
( 1)
100$ ( 1)
-
-
35.0?;; (21)
53.3$ (32)
TOTAL
100$ (60)
155
TOTAL
TABLE 5.6:
$ cases lying within each dust foci,
group is listed for each radiographic category. Absolute numbers
given in brackets.
< 150
150 - 299
300 -f
DUST FOCI
DUST FOCI
DUST FOCI
TOTAL
o/o
31.2$
(24)
35.1$ (27)
33.8$ (26)
100$ (77)
0/1
13.3$ ( 2)
26.7$ ( 4)
60$
( 9)
100$ ( 15)
1/0
50$
-
50$
( D
100$ ( 2)
( 1)
1/1
-
-
V2
-
-
2/1
-
-
2/2
-
-
-
-
2/3
-
-
-
-
3/2
3/3
3/4
-
-
-
-
-
-
-
-
-
11.7$ ( 7)
53.3$ (32)
P.M.F.
-
100$
( 1)
'
100$ ( 1)
-
35.0$ (21)
T O T A L
100$ (60)
155
$ of cases lying within each dust
TABLE 5.7: Small irregular opacities.
foci group is listed for each radiographic category.
Absolute
numbers in brackets.
73.
PMF
M
F
*fi.2# (35)
38.856 (33)
20^
UNCATBGORISED
7.3^ ( 3)
29. 3# (12)
63.^ (26)
100^ (Vl)
P
2.6J6 ( 1)
H.7 (17)
52. 6# (20)
100^ (38)
q
3.6^ (33)
45. 8£ (38)
50.6f^ ( k 2 )
10055 (83)
1^.3^ ( 2)
85. 7#
100^ (14)
0/0
-
r
TABLE 5.8
TOTAL
( 17)
100%
(85)
Small rounded opacities, % distribution of M, F and PMF cases
within each opacity type.
Absolute numbers given in
»Y»af lr <
RANK GROUP 2 HFI
RANK GROUP 1 WE
M
F
PMF
TOTAL
0/0
2
5
-
7
0/0
10
UC
-
1
3
k
uc
p
q
-
1
1
2
-
2
1
r
-
-
TOTAL
2
9
PMF
TOTAL
9
5
24
-
if
k
8
p
-
6
3
9
3
q
-
7
9
16
-
-
r
-
1
^
5
5
16
Tom
10
RANK GROUP 3 VTB
F
PMF
TOTAL
10
11
8
29
uc
-
2
5
p
-
if
q
2
r
TOTAL
27
2.5
62
RANK GROUP k AMYNX
M
0/0
F
M
F
M
PKF
TOTAL
0/0
2
3
1
6
7
UC
1
2
6
9
5
9
P
2
6
8
k
10
16
q
13
13
27
-
-
3
3
r
1
3
4
12
21
31
6it
21
29
5^
F
PMF
TOTAL
0/0
5
3
3
11
uc
p
q
2
3
2
2
TOTAL
-
7
k
RANK GROUP 6 PCSQJ
M
r
1
TOTAL
RANK GROUP 5 KOLGUDZ
-
-
M
F
PMF
TOTAL
8
0/0
C
2
7
UC
-
-
if
4
2
4
1
2
3
6
8
7
15
p
q
-
if
2
6
-
1
1
-
1
1
16
15
33
8
10
25
.
X
-
TOTAL
7
-
i
Table 5.9?
Small rounded opacities. Distribution of M, F and PMF cases
and category 0/0, UC (uncategoriscd), p, q^ and r cases within
rank groupings.
75.
No. of dust foci
r
q
P
< 1,50
13. 3?*
(2)
11.856
150 - 299
2<#
(3)
37.2/i (19)
69.256
(9)
300 +
66.7% (10)
51*
(26)
30.8?;
(4)
100^
(3D
TOTAL
100#
Mean total dust foci
330
-
1007£
(13)
27^
302
26.8
Standard error
TABLE 3.10
(15)
(6)
19»70
17.6
Small rounded opacities - all cases.
% distribution of each type of opacity into 3 total
dust foci groups.
Mean total dust foci and standard errors also given
for each type of opacity.
No. of dust foci
q
P
< 150
11. UJ
150 - 299
(D
-
300 +
88.9#
100*
TOTAL
(8)
(9)
r
-
10.756
(3)
28.6?6
(8)
50#
(1)
60.7% (17)
50^
(D
100^
(2)
100#
(28)
«
Mean total dust foci
Standard error
TABLE 5.11
372
3^.3
31^
24.0
319
-
Small rounded opacities - non PMF cases.
% distribution of each type of opacity into j; total
dust foci groups.
Mean total dust foci and standard errors also given
for each type of opacity.
76.
PATHOLOGICAL GRADING OF PMF
RADIOG8APHIC
NONE
GRADING OF
A
LARGE OPACITIES
B
C
None
Ap
Bp
Cp
138
3
3
-
37
6
6
-
11
1
187
7
-
16
TOTAL
Total
26
1
7
k2
15
-
15
1
'*5
23
261
-9
TAoLE 3.^12
Comparison of paUiolciricnl nnd r.r-;dioir;r3phic grading
lesions.
(Pathological grading is identified by
subscript p).
* denotes cases in which an average score could not
be produced from the individual readings.
None
NONE
A
X
B
1
C
Bp
Cp
38
18
7
2
20
15
5
6
•*
M
-
TOTAL
i
I'+O
Ap
-
g
;
'•
]
^9
'•5
o~z
i
Ap
Bp
Cp
27
16
1
A
136
6
•*!
22
B
2
6
_
21
""
Bp
Cp
**
2
6
26
15
10
131
6
1
7
1
2k
2
7
19
261
1'^
^9
k^t
23
Cp
C - Reader 3
None
C
Ap
198
15
k2
6
A - Reader 1
NONE
i
i None I
;
j
1M*
^
i
Total
I
1
_
Total
Hone i
Ap
Bp
165
1^2
38
11
kk
1
6
5
_
3
30
~
1
1
5
17
^
18
""
*
TCT/iL ' l^-'r
\ 23
:
261
!
-
T*if
i
'
-
i»9
;
;
>5
_
-
Total
191
10
7
16
-
23
^
16
1
261
B - Header 2
D - Reader
TAMI.S 5«1"5 A - D.
Co-np.'u'ison of patholrr;icnl and rr.dio^ranhic ^r.?.dinR
of P!\'.'' legion." for c-'ich ror.doi' l:pkc;n r:on-'>nt'-:].v.
Category
No. of Cases
Total
Dust
(SIPIS;)
Total
Coal
Urns)
Total
Ash
(rrr:s)
Total
Cu.?.rtz
(pns)
Total
K -!• H
(,-r.s)
% Coal
;•• l.sh % Quartz % K + M
0
83
9.:-7
6.8?
2.83
0.42
1.81
68.7
3'. 3
4.9
20.4
1
41
17,00
10.55
6.45
1.15
4.36
60.7
3<.3
7.1
26.1
2
11
?3.;>0
15.68
7.64
1.28
5.56
62.6
3r.4
6.4
27.3
3
3
27.1-2
17.42
10.00
1.74
6.89
60.2
3('.8
7.7
26.9
49
13.21
11.40
6.80
1.20
4.46
59.0
4'.0
7.4
27.0
FMF Ap
1
FMF Bp
44
PMF Cp
ALL PMFp
.
21..:8
13.92
7.36
1.24
5.02
61.0
3? .8
6.7
26.8
' 22
23.15
19.43
9.40
1.53
6.76
62.7
3- .3
•7.3
25.6
115
21.25
13.97
7.38
1.28
5.01
61.0
3^.0
7.0
26.1
:
,
TABLE 5*14
Mean values of total dust, its components and % composition lor raciiographic
categories of sme.'.ll rounded opacities and PMFp.
Radiographic
Rank (Jroup
i with Collieries Category
No. of
Caso;;
Total
L Coal
Total
Ash
Total
9.63 8.18
8.18
11.06
34.46 29.55
1.44
0.21
2.90
0.46
4.91
0.85
Total
Dust
Quartz
, Total
K + M
'
%
%
%
Ouprtz
K + M
Coal
Ash
1.17
81.?
18.1
2.7
14.C
2.35
3.88
74. c
26.2
4.2
21.2
83. 6
16.4
2.7
12.9
1.23 77.3
2.95 76.S
4.50 75.^
22.7
3.3
15.6
23.1
24.6
3.4
3.9
16.9
18.7
2.09 70.7 29.4
2.90 73, * 26.6
3.83 69.5 30.5
4.5
4.9
5.7
20.2
17.1
20.7
2.52
6.24
6.1
24.6
10.5
35.7
31.3
•
1
"]
0
Q
WE
1
1
PMFp
c;
,
!
!
7.77 5.85
19.78 15.77
26.25 20.36
1.92
0.26
4.02
0.59
0.91
11.67 8.67
18.59 14.19
19.72 14. 18
3.01
4.40
5.54
13.08
16.48
3.99
9.08
8.RO
0.64
29
9.09
7.39
20.20 11.39
14
7
'•5
8.71
16.78
18.64
4.60
6.60
6.60
4.11
0.57
1.78
2.24
2.29
2.74
4.84
0.45
0.90
1.61
3.50
7.04
1.25
4.35
2
0
23
HFI
1
PMFp
9
27
3
0
22
VTB
1
1C
PKFp
3C
4
0
11
AMNXY
1
10
PMFp
5
0
KOLGUDZ
1
5.89
0.49
0.77
1.00
1.79
1.50
5.72
62.3
47.3
5L7
37.7
52.7
48.3
53.5
40.1
37.0
46.5
59.8
63.0
60.0
59.0
48.0
•'-0.1
8.5
CO
I
i-
PHFp
6
0
FCSQJ
1
9
4
PMFp
10
6.93 •4.20
5.06
9.90
6.86
13.89
10.17
12.04
6.33
7.71
7.4
10.4
11.9
27.9.
37.3
41.1
6.3
7.6
9.8
23.0
27.5
31.5
41'. o
52.0
;
TA.BLS 5.15
Mean value of total dv.,3t, its components and % composition for raîo^raphic
categories 0 + 1 of small rounded opacities and PKFp.
TYPE
No. of
Cases
0/0
68
uc
p
14
18
Total
Dust (gms)
i "
t
TABLE 5* 16
41
2
Total
Quartz (gms)
Total
K+M (gms)
9.04
6.51
2.53
0.38
1.60
(1.00)
(0.84)
(0.26)
(0.04)
(0.14)
11.87
7.96
3.91
0.56
2.55
(2.70)
(2.26)
(1.03)
(0.10)
(0.57)
23.09
17.48
5.74
0.93
4.02
(2.78)
(0.76)
(0.15)
(0.54)
9.20
6.96
1.25
4.76
(1.15)
(0.94)
(0.76)
(0.15)
(0.53)
12.93
6.96
5.97
1.06
(0.98)
(2.23)
(0.7D
(2.85)
q
Total
Ash (gms)
Total
Coal (gms)
16.17
i
(3.21) •
°o
%
Ash
Coal
f
c
/o
°0
Quartz
K+M
4.6
19.6
69.9
30.1
(1.79)
(1.79) (0.34)
63.2
36.8
( 4.60)
(4.60) (1.04)
71.3
28.7
6.0
^.7
(1.C9)
24,0
,(2.38)
19.5
y
NM
(3.49)
(3.49) (0.66)
(2.19)
57.1
42.9
32.0
(3.28)
(3.28) (0.72)
(3.76)
4.66
55.5
44.5
34.9
(2.36)
(21.4)
Mean value of total dust, its components and % composition for each type of opacity.
brackets.
7.7
7.8
(21.49) (4.88)
!^
(15.5)
Standard errors are given in
*
.
i
o/o
;
0/1
i
i
•lean EH2 (/30)
! 63.4
i
1
3.16
! 66.7
j
i
| 3.28
Standard Error
I
j
i
Vo
1/1
1/2
2/1
2/2
65.2
67.6
66.2
66.0
63.0
2/3
3/2
.-•/ .^' ; ^/
0.57
0.83
60.7
63.0
-
:
—
i
-
2.55
3.6
2.54
2.2
5.66
3.5
''.17
-
0.64
0.84
1.01
1.11
4.70
0.50
0.88
-
i
Range of EH 2 (/30)
J with BH2 = < V30
j
0-21
|
45
i
TABLE 5.17
0-12
0-10
0-18
0-10
0-6
38
35
50
38
20
21
20
8
13
5
0-15
2.5-*
0-4.5
0
0
3
3
;
!
j
j
j
i
: -
(-.
Q P.
i L; > iv
4.58
0.43
,
I
•Jo. of coses
PMFp
i
|
I
•lean A.ê
• - - --
65
j
!
-
:
-
0-22
17
i
3
;
Comparison of emphysema estimations and radiographic category for small ro ;nded opacities.
;
-
110
0/0
-i/0
; 0/1
1/1
1/2
< 1/30
145. 5;^
(30)
•
: 2/2
I
1
BH2
2/1
58.ir<
(3)
35;v
(7)
50%
(*0
3?'.5?o
(5)
1C#
i;
5^
| 37.55(3)
(9)
^6.1?<
(6)
i
; 2/3
•
2Cfo
-
33.3;-'
j
3/3 | 3/4
3/2
_
rx?p
i "7. ;-;
-
(i)
(1)
:
(19)
i
1 < 5/30
2U.2£
(16)
(<0
6o?o
-
(3)
-
66.^
100J;
(2)
(3)
5 < 10/30
10 < 15/30
I6.75i
(11)
33.3^
(7)
9.1%
9.5^
(6) |
> 15/30
I
ioc£
12.55:
15. 9£
(i)
(2)
(D
-
-
(i)
33.3?i
(D
33. y/c
—
-
! ioc?b
-
33. 5^(1)
_
_
•-
-
(1)
-
-
-
-
i
.
(20)
Ii
ioo;<
(8)
(13)
10C5S
(3)
10(#
(3)
100%
(3)
10C$
(3)
23, &
(26)
_
•
(66) i (21)
TABLE 5. ^8
20^
!
-
!
TOTAL
-
-
5fi
(2)
r--./ '
-(3)
15?;
(3)
(50)
.
t
tfj.irv
ro
10. 9*
(1?)
2.7f<
(3)
-
10#
: (110)
% distribution of cases within ench radi o;-:ra ->,ic category over the 5 Brian
Heard groupings.
Absolute timbers in brackets.
o/o
0/1
1/0
1/1
63.7
67.3
65.2
69.8
3.^
7.9
5.67
2.7^
1.76
o-i8
0-9
1/2
2/1
2/2
2/3
3/2
V"*^
^•/
3A
R-'Fp
-
-
-
-
-
-
6B.8
I
Mean Ag-s
Mean BH?_ (/30)
2.3^
5.^
Standard Error
0.3^
1.2*4
0-1?
0-21
Han.r:e of BH2
(/30)
1>3
0-7.5
66.2
^.58
-
-
-
-
-
0.^3
_
0-22
,
# with RH2 = < 1/30
No. of cases
^9
13
20
0
0
106
23
5
5
5
_
!
1
!
:
_
-
-
-
_
_
_
—
I
A3L5 5-19
Comparison of emphysema efitinations .and radiographic category for small irregxilar opacities.
17
110
EH2
<
1/30
0/0
0/1
1/0
1/1
**9.1#
13?' •
2C£.
-
(52)
(3)
3l.l>t-
V5.3/:i
(33)
(10)
1/2
'
2/1
2/2
2/3
3/2
3/3
3/^
-.
-
-
-
-
-
17. Jfi
(19)
fn
^^
^
^
^
_
^5.k~i
(1)
PMFp
"
-
1 < 5/30
2C&
(1)
20#
33.5^
(D
(1)
(50)
A
5 < 10/30
(15)
6M
8.7?;
(2)
(3)
33.3?;
—
^
^
^
..
(D
(3)
23.^;
(26)
•
10 < 15/30
>, 15/30
TOTAL
TABL5 5«20
(5)
26%
(6)
0.^
8.??.;
(1)
(2)
^.7%
1006
(106)
100^;
(23)
_
_
2O;i
33.3?^
10. 9£
—
(1)
(1)
_
_
-
-
(12)
-
-
-
-
2.7=6
(3)
100/o
100^
(5)
(5)
_
100^
-
(3)
—
_
_
~
100;^
(110)
Small irregular opacities. % distribution of cases within each rad:.ographic category over the 5Brian Heard groupings.
TO
V/J
fl'l.
S.K.O. only
ALL CASiJS
0/10,'*..
3.07 ( 100)
'u';7 (3'i)
8.10 ( 2 ' f )
Standard error
0.39
0.78
1.08
/ ..\
•"'• ' "• ' ''
/T .' ^
,.--••
1.',6
1.99
l.f
I'.tVJU
: ..: \
D.U.
Stnndord error
ALL CASES
S.I.O. only
Kcr.n BH2
.
I . U . . - J ,-j'
S.R.O. + S.T.O
O.'O
'/. v.lth BIi;> <'/30
j.'ON-i-1--::-- c;-.".:'s :.'• with «•;? <i/30
33?;
/
V
^^ ^
X -
17.6>;
^.255
9.1S5
1 1 . 1?'
'•7.5:'
TA)'l.""j 5.21: A co'v.vorison of cp!nliynor:a in cnsos hnvinr; cither sirall rounded or small
irrci-u] or o;>nciticn oi' tlie two in co:i\bin;jt.:i.on.
N'urr.'ner of cases pi.vou
in bracket.';.
:,H2 F-miYSEVA GROUPIES
< V30
1 < 5/30 5 < 10/30 10 < 15/30 5. 15/30
«?; ( 3)
''9;j ( 1-0
2?;; ( 10)
1C;,; ( 6)
q 3')?; (2?)
'+3?< (3'0
15?'. (12)
(>% ( 5)
r
':^ ( 6)
'«3^ ( 6)
1'tf ( 2)
p
11£ ( 2)
.%r' ( 10.)
KON-PKF
CASKS
• q
39ii ( 16)
i»'^ ( 1S)
r
50;:; ( 1)
-
p
ALL
CASKS
<
-
3?; (2)
-
TOTAL
;.;:^'
^£ofD
•100;: ( 3 V )
'i. 4
U.t>'l
100,V, (to)
3.3
O.'i9
100?; ( i'o
1-9
0.72
100?; ( 18)
100?; Cti)
100?;; ( 2)
3.5
0.59
2.7
0.6'i
3.0
3.11
V.
TAM'!LJ5jL22_.:
<•
6?; ( D
7;; ( 3) 10?; ( 4)
50?;. ( D
28-S! ( 5)
_
-
•
E'liphyô-a estir,ntions for three types of snail rounded opacities.
casea Rivon 'j.ii brackets.
Nun:ber of
60_
"^™
NUMBER
OF
CASES
H 261 CASES
so.
__
45.
Jl
40 _
X
c >
35 _
X
_^_
X
X
c >
X
c >
30 .
X
25 .
X
^X
X
<
X
20.
C
>
X
X
>
X
<
>
<
X
x' x
X
X
>
I—I
X
K
X
X
X
X
^w
X
X
X
>
X
)
X
; x
< X >
x x >*>? x x
1
1 *\
«J •.
X
.,'
X
X
X
X
X
X
X >
X X
-*x
'v
> nn__
>
: x x x x >
x
k x >
x
x x x x x x
: > 1x x
>
__
; x x x x >
f— x
k x >l——,
x —. I
x x x x x x
1
>
f X X X 1
>
1
1
_
,
x x x x x > —1
x L_Jx x x x |
x
11
k>
X X x x x x x x
:
x
x
x
x
x
<i
<
>
«—
I
1
x
Hr"
_< x x : c x x x x >
X X X X X X X X * M —|
|A A. X X
x x x x x x x x
jrHc x x x x x x x x x|
(—jr x x x "~1
< x x : : x x x x >
1 X X X X X X X X X X
[
f —>
JX X X X X
1
x x x x x x x x TT"V x x x x x x x x x x^rr'x — < x x x v *--<]
f x x : x x x x > x x x x x x x x x x x x x H | x x y y"v' - 1
10_
•
_l
w
V—
E H F I V T Bj A M N X Y K O L G U D Z P C S Q J
•*
"
-
1
2
C O L LIEF
COAL RANK GROUP
FIGURE i).1. DISTRIBUTION BY COLLIERY OF 261 CASES WITH RADIOGRAPHS
SUPERIMPOSED UPON THE STUDY GROUP OF 530
NUMBER
NUMBER
OF
OF
CASES
13
°-
I
]
3
261 CASES WITH R
CASES
120.
110-
220-
100-
200-
•
90-
180-
80-
160-
70-
140-
60-
1 ?f)_
Px >
xx>
k x x x x
, x > x x >
X
50
X
40-
X
X
X
: x
X
v
t ft
3
0-
X
X
X
X
X
x
X
X
v
X
X
X
X
v
>
X
X
X
X
>
X
X
X
X >
X
>
X
X >
X X
X
X
x > x
X
X
X
X
v
X
>
v
; X *
'. X X
100-
X
X
X
X
X
X
X
x
X
X •>
v v
>
X
X
X
X
X
X
X
X
X
X X X
40••"" - ^
on
«£ U -
'
'""••'•'.
x x x x x x x x x x x x x x x x x x >
v - x ;-' x x x x x x x x x x ; x x x x x x x
3640
4145
4550
5155
56- 6160 65
6670
71- 7675 80
x
X
X
8185
AGE
IN
X
X" X X
X X X
X > V
x :< x x
x x x; *
x :< x x
X
X
x
X
XX>
X
x
60-
x x x x x x x x x
X X X X X > XXX
XX
x x x x x x x x x x x
X X X X X X >
X X
X X X
rr-JTT x x x x x x x x x x x
' " ' • ••"•\ x x x x x x x x / x x x x x
! X
x
80-
x >
X
X
X
10 -
^"^•^, : x x
X
x x x x x x > x x >
x x x x x x x x x
x x x x x x > x x >
x x x x x x x x x
20 -
I
x
x
X
X
>
>
>.
X
:< x x
:< x >
x >. y
X
.<
X
>
x x. x x
•; x x
< x x x x x >:
X
X
X
.<
X
X
X
X
X
X
<
X
>
X
X
X
X
<
X
>
x
x
X
>
X
x x
X
X
x ^. >:
x x x x x x >:
X X X X
< X >
x x x x x x >:
M F F:1MF
YEARS
FIGURE 5.2. DISTRIBUTION BY AGE AND PATHOLOGY GROUP OF 261 CASE:, WITH RADIOGRAPHS
SUPERIMPOSED UPON THE STUDY GROUP OF 500.
PATHOLOGICAL
TYPE
7 5 0.0 n
600.0.
4 5 0.0.
H
2
TOTAL DUST FOCI
3 0 0.0 .
*
*
*
*
*
*
*
*
2
*
*
K
*
*
2
*
*
3
2
150.0.
*
z
2
'*
5
*
3
*
0.0
0/0
0/1
1/0
I/I
1/2
2/1
2/2
2/3
3'2
RAOOGRAPHIC CATEGORY FOR SMALL ROUNDED OPACITIES
FIGURE
5.3.
DISTRIBUTION OF TOTAL DUST FOCI COUNTS FOR RADIOGRAPHIC CATEGORIES OF SMALL ROUND
OPACITIES.
P. M. F. CASES EXCLUDED
58.0^
52.0.
&
48.0.
*
4 2.0.
*
36.0.
*
*
*
*
OTAL DUST
30.0.
*
*
*
tf.
*
*
IN gms :
24.0.
18.0.
S
*
a
4
*
12.0.
8.0
4
2
4
6
*
7
9
7
0.0
*
*
*
*
0/0
v
*
2
2
3
2
3
5
*
*
^
3
*
2
*
*
«
*
*
5
3
*
*
0/1
1/0
1/1
1/2
2
*
«
*
2
tf
2
&
2/1
2/2
2/3
3/2
RADIOGRAPHIC CATEGORY FOR SMALL ROUNDiD OPACITIES
FIGURE 5.4.
DISTRIBUTION OF TCTAL LUNG DUST CONTENT FOR RADIOGRAPHIC CATEGORIES OF SMALL ROUND
OPACITIES. P. M.F.
CASES EXCLUDED
P-9.
KS AyF:;;cTTr!G ^niYsa^
IK' Tlii'J l i i ' . S OF
In the present study, data on the overall level of emphysema, as
measured by the Brian Heard method, were avs.ilsble from ^50 out of a
total of 5^0 cases.
Fifty esses were excluded either- because the
lungs had been found unsuitable for emphysema estimation or because
no smoking history was available.
Simple comparisons of the effects
of age , smoking history, pneumoconiosis, coal rank, limp; dust and
dust exposure on levels of emphysema were undertaken and the data are
j.ii GOCiiLcd iix dctr.il ir. the rrr.ir. v<c^y ?f
*"Vr- rV.n-.^t-pr.
Tho r.n-i n
findings are summarised below:
(a)
In this group of coalrciners the prevalence of emphysema was
found to be acre-related for smokers but not non-smokers,
although only l*5 cases fell into the latter category.
(b)
The percentage of men with emphysema increased between the
pathological types of pneumoconiosi s M, F and PHF.
The overall
l
fipures were \7& for M cases, 6'<?o for F cases and 82% for PMF
cases.
Smokers, ex-smokers and non-smokers a]] showed this
effect but to a variable degree.
(c)
For the whole group there was an association between the
occurrence of emphysema and lung dust content.
This is part
of a complex relationship between age, smoking habit and lung
dust content which is explored in the text.
(d)
In 181 smokers, aged between 66 and 75, there w«s no linear
association between the extent of emphysema and the lung dust
content or its composition.
(e)
In '^ smokers from this group for whom satisfactory dust
exposure data were available there was no simple relationship
between the mass and the composition of inhaled dust and the
extent of emphysema.
6.1
The effects of arc and smoking history
As the first stage of this study, emphysema as recorded by
the Brian Heard method was compared to both the age and smoking
habits of the men, since these factors have been shown to
influence the levels of this disease (RYDEii et al.,
AM DESIGN vt_ al. , 1971 ).
1971;
The age distribution and smoking habits
of the k[}0 men in this study are shown in Table 6.1 and
90.
comparisons of those two factors with the prevalence of emr>hyr;cma
are presented in Tables 6.? - 6.8.
These comparisons suggest
that in the population under study, the occurrence of emphysema
has boon influenced both by the age of the man and whether or
not he was a smoker during his life.
Although the numbers are small at the extremes of the age
range, there is an increase in the percentage of cases showing
recognisable emnhysema with increasing age.
In addition, the
range of BH2 estimations is greatest between 61 and 75 years.
Of men
between '.yi o.r.ci ',".) WHO
least yjf0 (BH2 >
1'so erriTinyseina, ore-ij.itn na.u ax
10
/30) of their lung tissue involved (Table
6.5).
However, men over ?6 years showed rather '.lower I-H^ levels and may
represent a survivor population in terms of respiratory disease
(Tables 6.2 and
6.5).
There was a considerable increase in the percentage of
cases showing emphysema between non-smokers and smokers.
Ex-
smokers, although falling between these two groups were closest
to the srokers (Table 6.3).
They also had the highest
percentage of cases with more than one-third of their lung tissue
affected by emphysema (Table 6.7).
Ex-smokers are known to
represent a special group whose charge- in smoking habit may have
been due to the development of respiratory disease.
When the
effects of age and smoking pattern were considered in combination
emphysema increased regularly with age only in smokers and to a
«
lesser extent ex-smokers (Table 6.*0.
A similar relationship
between age and emphysema is not apparent in the group of nonsmokers.
6.2
Levels of emphysema and pneuwoconiosis
Levels of emphysema recorded for all cases were compared
with the presence and pathological type of pneunioconiosis within
the lung tissue.
This was done both with, and without taking
smoking history into account and the results are shown i.n Tables
6.9 - 6.11.
Tables 6.0 and 6.10 show that within this
ponulatior., the percentage of men with recognisable emphysema
increases with pathological type and 8,?.3/:i of men with PMF
showed evider.ee of this di.sease.
This association is so marked
that an age effect is only d:i scernahl e in cases with soft
91.
macules.
In cases with cither fibrotic nodules or PMF, the
presence of pneumoconiosis appears more important than age in
the development of emphysema (Table 6.10).
The effects of
smoking combined with pneumoconiosis in the development of
emphysema are illustrated in Table 6.11 and from this data it
would appear that the prevalence of emphysema increases with
smoking in cases having either soft macules or hard fibrotic
nodules.
The prevalence of emphysema in PMF cases is high
regardless of their smoking habits.
As shown in Table
6.12,
the •nercontape of PMF cases who are smokers is lower than for
the other pathologic al types and the percentage of ex-smoke ro
is higher.
6.3 . Emphysema and the effect of coal rank
Emphysema estimations were plotted separately for the
cases from each colliery and the collieries were grouped by
coal rank as described in Chapter 3in Table 6.13.
These results are shown
No statistically significant differences are
apparent between the levels of emphysema for individual
collieries.
However, the series of men were highly selected
for the presence of pneumoconiosis and not emphysema, so that
these figures would be unlikely to give a real comparison
between emphysema levels at the different collieries unless
pneumoconiosis was by far the most important cause of this
condition.
6.^
Emphysema and lung dust
Lung dust measurements were available for Mt1 out of the
men.
The levels of emphysema, found in these men, compared
to total lung dust and to the mass and percentage composition of
its constituents are shown in Tables 6.1^ and 6.15-
From these
data it would appear that the prevalence of emphysema rises with
increasing lung dust and coal content.
However, the data
previously described indicated that age and smoking history may
play an important part in the development of emphysema and it
was decided, at this stage, to limit analysis of dust and
emphysema relationships to smokers aged between 66 and 75 since
this 10 yr age span contained the greatest number of cases.
One hundred and eighty-one out of the ^50 men fell into this
category.
9?.
A comrx; risen of 1 eve Is of emphysema and pneunocoriiosiK in
this Gubrroup of men in shown in Table 6.16 rp.d it can be seen
that the nr.rc entire of cases with emphysema still increnyes
vi th t.H; severity of •prieunoooniosis.
Tables 6.17 and (S.1o show
corrroarisor.r, of the levels of enrol >ysema. and. the Inn? dust
extracted from these 181 cases.
Statistical analysis shows
that there it; no linear association between either the total
lung dust content or the lung dust composition and the percentage
of emphysema present in lung tissue.
This observation is in
ttrrrpc.mpr-, •)- -,.;-• M- f.v r. rnr^lnr f "i r •! -I n ™ .". in rr;"l nti on to cocil rank.
6.5
Dust exDQgur? and orrîhyscma
As reported previously in Chapter ^.2, satisfactoi-y dust
exposure data were not available for all the men involved in the
present study and it WPS decided to examine the effects of dust
exposure only for men whose dust dose had been measured for at
least 20/c of their working lives and. who had worked for 5Q~' of
their working life in the some colliery.
Since total dust
exposure is very likely to be arê-related, the effects of duct
exposure on the development of emphysema wero separately
considered for the proup of men between 66-75 previously used in
r
'/-.^J-^««
f-*v.'«»
\\ <•
*^ V V* I. j. ^ 1 i
requirements
O f**.i 4-V»r»
lP.1
*>•«*-> •? J.
r\ . ^ 4-Vi-tc:
r*V^ >"(•-.ou rrr,-r\r
r\r> 1 îr..i./4
il. nir^-f
4->iia ',..'...
i-l.s'.. ' il.%'»i
ui._>^
>. ,. , , , - ^.
^^
" !
..1. V
regarding exposure data.
For these men, comparisons
of emphysema levels r.wl exposure to the various dust components
For this grotip it appeared that there had been no difference
.in exposure to total dust or coal, ash, quartz, kaolin and mica
considered by mass and the levels of emphysema present in l.unp;
tissue.
Similarly, no simple relationships were found when the
percentage composition of the mine dust was compared to emphysema
levels.
6.6
An invest i r- ati on i n to the facto r F related to the
nrosfr.ce of e 7 f ; o ; ; ! a
It has been noted in this chapter that there is an observed
increase with sf;e in the percentage of cases showing recognisable
emphysema at autopsy.
This percentage is also seen to be higher
for smokers than non-smokers.
Preliminary statistical analyses
relating: levels of cn^hysetna to are and stnokinp; habit suggested.
that ex-s: olcers behaved as smoliers in this context, although the
93.
overall relationships considered proved to be non-significant.
For these reasons, the small number of ex-smokers involved in
this analysis have been grouped with the smokers.
There are several methods of relating the prevalence of
emphysema to possible influencing factors; the mathematical
model described below is only one of these.
The probability
of emphysema being present at autopsy (denoted by "p") for a
particular case is expressed in terms of a linear function
(denoted by "f") of explanatory variables.
.•-'•*._
V GLJ. J. CA I./J_ 17 O
II l*-*^
i-
UV>
Of-',O ,
These explanatory
.% r _-.... l.^-i-.? x
1
i.._i . . . j _1_ i.
Ul.lwm.llfj, lli-**>J.vj J.UMl.rj ^ \**-J \* ><v*.l.fAllt*,
._
on IJf
_ A.I. .
variable or any combination of variables selected by prior
knowledge of factors connected with the disease or by the
hypotheses of interest.
The relationship between p and f was defined to be:
which is the standard logistic formulation.
Several expressions for f were considered using the variables
mentioned above, together with radiographic category within four
years of death and type of opacity (for cases where this
information was available).
Further work is needed on these
analyses and to find the formulation that best -describes the data.
The function reported here is of the form:
f = ao + a1 if subject ever smoked
+ £fe x lung dust weight if ever smoked
+ 83 x lung dust weight if never smoked
+ a* x age
where ao , aT , as , a3 , 34 were estimated using the statistical
technique of maximum likelihood.
Four hundred and nineteen cases
were considered.
The estimated coefficients together with their
standard errors are given in Table 6.21.
This model was found to give close agreement between observed
and expected incidence when tested on data grouped for convenience
by age and smoking habit (Xs statistic for goodness of fit = 1.82
with five degrees of freedom).
As an example of the use of the model, consider a m-?.'n v/ho
was aged 67 years at death, who had lung dust weight of 1o.9 grams
and v;'no had r.or.e history of smoking.
He would be calculated to
have a probability, p, of having emphysema at autopsy of:
}°£ -fa = -7-57 + 2.56 +(0.05 x 18.9) + (0.08 x 6?)
so p = .78
A man of the. same age and lung dust hut who had no history of
smoking would have a probability of 0.51 of having emphysema at
MU. LO'ptiy •
v^ .L t? ci i ' j J
cuv.' uiuurrj. i . i . c t - ~ u j.o ujij.j
VC^J.J.\A i *_-o.
tjj. c=ô.w o^.wn>->
over the range of observations.
This model demonstrates the effect of age, lung dust weight
and smoking, and to some extent suggests that whilst smokers have
a higher initial probability of suffering emphysema, lung dust
weight is proportionately more important for a non-smoker.
Clearly, given that the coefficient of lung dust in the fitted
model for non-smokers is higher than for those v/ho have ever
smoked there will be a level of lung dust where the estimated
probabilities for the tv/o groups are equal for men of the same
age.
Above this point the estimated relationship would give a
higher probP.bi'J ity of having emphysema at. autopsy for a non-smoker
than anyone who has ever smoked, for a given lung dust.
lung dust level is at 3^.6 grams.
This
This possibly means that the
The fitted model should not be used for estimations at such dust
i
levels given the range of casesv analysed.
A similar formulation for f has also been used to examine
whether a similar relationship may be observed using dust exposure
data rather than lung dust data.
Data from 116 of the 119 men
selected for good exposure data were available.
for f used in this analysis was:
f = bo -» bt if subject ever smoked
+ bs x dust exposure if ever smoked
•f b3 x dust exposure if never smoked
+ b4"'X age
The expression
95.
The coefficients bo, bj , be, b3 , hi wore estimated ns before.
Results are Riven in Table
6.22.
At usual levels of significance, none of the coefficients
are significant;
significant.
at the 10£j significance level only bj^ is
TV in r.ay be interpreted to reflect that 116 cases
are not sufficient for reasonably fitting such a mode].
However,
the model shows no significant lack of fit to the data.
Dust
exposure appears to be more important for non-smokers than smokers,
Riven the higher initial probability associated with ever having
smoked.
The ratio oi t>3 : 03 is consissvenu wilii UK* I <jf a3 . «?
estimated in relation to lung dust.
The coefficient of age is
reduced whilst the constant threshold is increased.
For the illustrative example considered above, -the individual
(a smoker) had a dust exposure of 190.8
probability being 0.63.
gh/m3, the associated
This is lower than the prediction by
the previous model.
This is clearly only a preliminary investigation into the
incidence of emphysema and more work is necessary into the
applicability of such a mode], before an authoritative statement of
the relationship may be given.
Further consideration of
radiological data may improve the model and it is hoped that this
will be carried out during the second phase of the project.
96.
ABC
Groun
76-80 81-85
36-'tO i*1-'i5 '(6-!50 51-55 56-60 61-65 66-70 71-75
2
Smokers
2
Total
TABLE 6.1
2
7
351
9
8
1
5<*
7
13
i»
2
1*5
121
108
52
10
'»50
36
55
97
86
2
2
15
17
1
1
8
9
8
22
^6
79
ExSmokers
NonSir:okers
to
19
7
2
Total
Age and smoking habit distribution of ^50 men with known emphysema levels.
Age Group
36-^0
i*1-'45
I
2
2
(#
Qt
No. of cases
c
/a of cases
with emphysema
(No. of cases)
i
(0)
i
'»6-50 51-55 56-60
61-65
8
22
^6
79
121
37. #
5^.55U
5'».»
59. 5#
71.9*
(0)
(3)
(12)
(25)
66-70 71-75
(V?)
(87)
76-80
81-85
108
52
10
7V»
78. &
(80)
100^
(10)
CtD
BH2 estimate
range
0-3
0-10
0-17-5
0-21
0-22
0-21
0-1 1*
Mean BHS
all cases
0.9
2.1
2.7
3.2
U.6
tt.O
2.8
3.9
Mean BH-, rases
with
empnysema
2.5
3.9
5.2
5.7
6.i»
5.5
3.2
3.9
TABLE 6.2
!
Prevalence and extent of emphysema in 5 yr age groups.
disregarded.
Non-smokers
No. of cases
Mean age
(SP-0
<<5
67. t*
Smoking history
Ex-smokers
5<+
(1.2)
68.5
(0.9)
Smokers
351
67.1
% of rases vn th errnhysorr.a
^2.?^
6'*.{$
71. 2#
BHa range
0-1 8
0-15
0-22
Mean BH 3 all cases
2.5
^.2
3.9
t-'ean B!is - case? w i t h er'r>hysemn
6
6.'f
5.5
TAB!K 6."5
1-11.5
Emphysema in the study population subdivided by smoking history.
(O.M
97.
-v^^
%^~-\
Age
Group
41-45
36-40
^-^
Of
46-50
51-55
56-60
61-65
66-70
71-75
76-80
43^
47.4-^
61*
63«cfo
75.25*
80.2-;;
(69)
80#
(32)
1CX$
(7)
50£f i - i
46.7;*
70.®. 67*
Cl-.l
. - • , , ( *C^
•• .
'1%
< c.\
10C*
( i\
7%
10<$
cases with ^~\^^
emnhysema
^""^
Smokers
(#
(0)
0$
(0)
(3)
Ex-smokers
t
(22)
(9)
1
1^
!
(35) "(73)
f ^
' ' '
81-85
I
Non-smokers
CBS
(0)
TABLE 6.^
36-40
41-45
2
2
1 < 5
f?)
(3)
5
10
21
33
34
28
11
0
146
3
7
15
24
39
41
25
1
155
5
7
10
28
27 •
12
5
94
2
9
15
7
«*
*
41
1
3
5
5
>15
i
. -,
^"\-^
BHS
(5)
51-55
10 < 15
TABLE 6.3
38.5$
46-50
5 < 10
m
44. 4# 28.6JS
(tO
(2)
I
^\^
< 1
(2)|
(1) i
The percentage of cases with emphysema shown within age groups for three
smoking habit categories.
Figures in brackets indicate number of cases.
— \Âge
^^
B,i?
ioc$ I 2%
^^
n
56-60 i 61-65
i
i f / 's .
!
66-70
- -, -
71-75
76-80
81-85 Total
14
I
- -n
,
Emphysema estimations in five bands for all cases.
Age
36-40 41-45
^\^^
46-50
51-55 56-60 61-65
66-70 71-75
76-80
81-85
Total
4
10
14
20
24
17
8
0
101
3
6
13
20
33
36
18
1
130
3
6
7
25
24
12
4
81
10 < 15
2
5
11
6
2
2
28
5-15
1
3
4
3
36
55
97
86
< 1
2
2
1 < 5
5 < 10
Total
TABLE 6.6
2
2
7
Emphysema/Age in smokers.
19
11
4o
7
351
BHa ^^^--.^
51-55 56-60 , 61-65 66-70 71-75 76-80 81-85 Tot a]
36-^0
< 1
1,8
5
^
1 <5
1
1 : 21
5 < 10
1
!
10 < 15
Lr5 ..
i
.
.
!
Total
?
!
I
TABLE 6.7
2
A e
j
3
it
15
I
1•
0
i
1
9
_: 2 -_ ** _! i
2
1
:
1
I 17
;
9
8
1
5^
76-80
81-85
Total
;
15
:
9
2
56-60
61-65
1
6
5
5
8
1
26
1
2
2
2
3
10
1
0
0
2
0
it
0
0
0
0
'\
5 < 10
10 < 15
2
66-70 71-75
1
1
Emphysema/Age in Non-Smokers.^
8
9
It
2
,
>: is
TABLE 6.8
19
'n-<<5 A6-50 51-55
1 <5
Total
2
Emphysema/Age in Ex-Smokers.
~~^\^ n
BHs ^^\^^ 56-JiO
<1
3
j
'
1
3
! 3
7
13
1
1+
2
J
>5
99.
No. of cases
Mean age
(SK'-<)
% esses with
emphysema
M
F
92
183
,
(1.0)
63.3
rT1
46 .-c.
(0.5)
82 3&
"
0 - 20.5
0-22
fr-
y-
1 -5
18
61
76
> 5 - 10
18
36
40
> 10 - 15
6
15
20
> 15
1
5
8
2.4
3.5
4.7
5.4
5.5
5.7
Mean Ws
all cases
Mean BHS with
emnhysenia
TABT.-K 6.9
"^^^^
Age
^^\^^ Group
Pa tholo^y ^"^*\^^
Emphysema levels in 450 cases subdivided by pathological type
(smoking history disregarded).
36-4o 41-45 46-50 51-55
C$
(2)
q*
(21
56-60 61-65
20^
(1)
37-5^
(3)
46 2J5
6ftS
6o#
(6)
47.8%
(11)
73*
(3)
80X
(8)
(2)
TABLE 6.10
(0.5)
':"
""_. ' '
Pl-iF
175
70
6'f--
0 - 17.5
BHj range
67
PMF
(6)
36.S"i
(7)
66-70 71-75
u i • 7/S
(13)
57*;
76-80
81-85
62. 3o
—
(8)
(5)
70^
62.55s 62£
(20)
(3D (33)
g^/
6c%
83&
(19)
(43) (39)
73.3*
(11)
100Jo
85£
(25)
10^
The percentages of cases showing emphysema subdivided by age and
pathological type.
Figures in brackets indicate number of cases.
(3)
(7)
100.
^--^
I'atho'lor;;,
Smoking
Habit
M
F
o>
5 -/,-.:
^~~"^^^
^^--^.
rion-sii-okers
(1)
k-',i
Ex-smokers
57*-i
(9)
^
69.6/0
(103)
8':.^
('40)
6itfi
(11?)
82 . 5;>
(1MO
nc. :!
| f J «.;
Habit
M
(100)
^^^«^.
11.%'
(11)
Ex-smokf-rs
7.650
(7)
Smokers
8
-
9.8-s
(16)
9.36
(17)
17.1&
(30)
°*"(7M
100v
(9?)
9.i?i
(18)
8o.S?i
100^
Total
PHF
F
i
j
"^x^,^^^
.on--..:C..,...r.
TABLE 6,12
(?3)^
The pfire'vritago nf c n r ^ n s v:i th emphysema for
tb;'-:f? v.-'^tb(ilo~:i c ; O typor; rii v:idcd by smoking
haMt.
Firurcs i n h r a c k e t o i n d i c a t e
num^nr of caês.
"~~^-^^_^
Pathology
^~~"~~\(j r ou p
i^fjf't)^
?6.7#
j
( ^ "5 )
TABLE 6.11
(1?)
(3)
£j /T
All cases
75?.;
(6)
5K
Smokers
PMF
73.?^
( 129)
10^
(183)
(175)
The percentage d i s t r i b u t i o n of smokinr;
habit, \ v i t h i n 7;nt.ho?i.ogical types in ';50
c«'isc'S.
Fi.!-).:re-:-; in b r a c k e t s indicate
nunibfjv of c^ses.
101.
^--^Pit
BUsT""^-^
^*^_
Pi t •
F1
I.
18
10
9
37
1 - 5
9
16
10
35
6
> 5 - 10
6
1^
2
2
2
> 10 - 15
2
3
2
7
1
1
2
> 15
0
0
2
2
19
23
't2
35
<*3
27
103
W
E
< 1
7
8
1 - 5
8
> 5 - 10
Total
BH^\!
H
13
< 1
9
1?
3
3
> 10 - 15
0
> 15
Total
Total
Rank Group 1
Total
,
22
Kank Group 2
~~--\Pit
V
BHP^^\^
T
~\^^ Pit A
BHa^-\_
B Total
M
N
X
Y
Total
< 1
22
12
2
36
< 1
It
8 2
8
2
2lt
1 - 5
16
18
3
37
1 -5
1
7 2
7
8
25
> 5 - 10
10
7
0
17
> 5 - 10
1
7 2
1
2
13
> 10 - 15
It
5 i°
9
> 10 - 15 2
0 0
3
5
10
> 15
A
4
0
2
> 15
1
0 1
0
2
It
5
101
Total
9 22
53 *+3
Total
|
Rank Group
Kank Group 3
~-\
76
19 19
.i
i.
'
rt
|
Pi t i . .
1 .
Pit i J] „ I T! „ ! , I
I
BK?~""~"-\
'"'
u
< 1
5
5
It
3 0 Itg 0
21
<1
2
't
it
1
12
1-5
7
2
7 3 1 2 1
23
1 - 5
1
5
5 1 1
13
> 5 - 10
0
2
7 2 5 2 1
19
> 5 - 10
5
6
2 2
1
16
> 10 - 15
1
3
2 0 0 0 0
6 '
> 10 - 15 0
3
1 1 1
6
> 15
0
0
0
0 0
1 0
<i
> 15
0
1
0
1
0
2
Total
13
12
20
8 6
9 2
70
Total
8 19
12
6
It
1*9
Rank Group 5
TABLE 6.13
i;
i '.!
'-' | -'
-
— O *~ c*. J-
JjHg
~~"~"^-^ I
]
".
!
1
•
Rank Group 6
Emphysema estimations for the men from individual collieries grouped
by coal rank.
102.
"\^
Total ;
^•vQust
< 5 pins
BH2
< 1
^^
5 < 10 1CK15
I
15<20 2CK30 3O<40 40<50
£ 50
Total
1
0
144
12 | 6
3
154
37
42
31
13
18
1 <5
14
32
31
24
32
5 < 10
9
23
20
19
9
8
1
1
90
10 < 15
6
8
9
8
<*
4
0
0
39
£15
3
3
2
1
3
0
1
1
14
69
108
93
65
66
26
9
5
441
Total
(a)
2
i
Total dust
r
\^ Total
;
I
^Câl < 4 gms 4 < 8 8 < 12 12<16 16<20 20<24 24<28 | 28<36 £ 36 Total
:
I
i
I
BHS
^\
K
21
144
1
<1
10
2 ;
1
0
53
51
9
8
6
5
7
7
^F
7
4
2
2 | 90
7
3
2
2
1
2
0 |
| 39
1
2
2
0
1
1
0
2
14
133
66
41
19
20
13
9
12
441
14<18
£ 18
Total
1 <5
31*
*5
21
19
5 < 10
22
28
15
10 < 15
14
8
5
128
5- 15
Total
(b)
! 15*
Total coal
"-^ Total
< 2 gms 2 < 4 4 < 6 6 < 8 8 < 10 1CX14
^-4sh
BHP
^\
<1
53
50
13
4
9
8
5
2
144
1 <5
27
38
27
-26
11
10
9
6
154
5 < 10
18
23
25
11
7
4
1
1
90
10 < 15
8
12
7
4
4
3
1
0
39
£15
3
6
3
1
0
1
0
0
14
109
129
75
46
31
26
16
9
441
Total
(c)
Total ash
TABLE £.14
The rcl.itionship between the mass of lung dust and its main components
end levels of emphysema in 441 men from the Pneumoconiosis Field
Research study.
For this comparison, nge and smoking were not
considered.
103.
^^
Total
^"\Q
i
< 0.5 gms 0.5<1.0 1.CK1.5
1.5<2.0 2.CK3.0 3.0<U.O
^».o
Total
^\
BHa
< 1
8<t
30
9
10
5
5
1
1M»
1 <5
5^
39
27
1i+
10
9
1
15^
5 < 10
31
3**
18
3
2
1
1
90
10 < 15
15
13
6
2
2
1
0
39
7
5
1
0
1
0
0
1A
191
121
61
29
20
16
3
fiifi
> 15
Total
(d)
Total quartz
^
Total |
^\K
+ M ! < 1 gm1 < 2 2 < 3 3 < 5
ms ^\ I
5 < 7 7 < 9 9 < 11
»11
'
Total
<1
kk
38
22
16
8
7
6
3
1^1*
1 < 5
19
29
30
33
21
9
7
8
15^
5 < 10
8
19
22
26
10
3
1
1
90
10 < 15
6
6
9
9
5
1
0
39
> 15
2
2
5
»
1
3
1
n
^
A
14
**5
23
15
12
Mn
Total
(e)
77
1
9*
88
Total kaolin and mica
TABLE 6.1U contd.
8?
104.
'v^Cofil
RH8 ^s. <25;'
<1
1
K5
3
2
500
1CX15
*15
2
0
5
TOTAL
25<35
35<45
14
19
11
5
7
3
3
0
41
'+5<55 55<65
2
19
15
15
3
1
39
53
16
65<75
75<85
31
22
33
39
24
7
3
106
16
23
13
5
3
60
20
13
2
««
35<95 $95 TOTAL
18
1
144
17
4
0
154
0
90
•*
s*
0
39
3
45
0
14
1
•
441
(a) Percentage Coal
^\
02*
12<20
2CK2S
28<36
3b<44
<1
11
28
20
24
12
K 5
5OO
11
21
32
22
19
11
9
11
3
83
1
13
13
4
1
1005
*15
TOTAL
3
1
15
3
3
™
2
69
44<52
6CK68
68<?6
>76
TOTAL
20
10
8
10
1
16
7
' 15
2
1
2
. 39
30
15
5
1
1
30
144
154
90
12<14
14<16
10
2
2
50
43
69
52<60
9
3"
1
4
3
0
32
14 .
0
___.
441
(b) Percentage Ash
^^CJuartz
BHs
f
<2?i
2<4
4<6
6<8
rr,
--
-* r\
^*-»
ir<J
50
32
-^1
C.C.
18
10
17
10
10
4
14
2
13
4
3
0
131
86
49-
8<10
10O2
>16
TOTAL
* I. 1.
^\
A
'< 5
5<10
1CX15
>15
TOTAL
4
2
3
44
ir
•
*» -»
i^:.
r%
{
A
16
4
O
c.
2
...____
2
17
7
1
1
41
3»
u
~^~~
90
2
3
„__. —
j9
1
0
0
14
31
15
'6
441
(c) Percentage Quartz
TABLD 6.13 The relationship between lung dust composition and levels of emphysema
in 441 men from the Pneumoconiosis Field Heseorch study. For this
comparison, age and smoking habit were not considered.
105.
"\# K+M
<5# \ 5<10 10x15
15<20 2CX25
25<30 30<35 35<'*0 kO*5
550 TOTAL
8
9
1
iMt
7
16
11
5
15"*
8
U
5
6
1
90
5
2
3
1
3
1
39
0
2
1
0
1
1
0
T*
65
W
32
28
31
30
8
Mn
<1
5 j 16
22
19
27
13
10
1 11
1 <5
1
18
22
29
19
15
11
5 < 10
0
it
17
21
11
13
10 < 15
0
0
11
5
8
»15
1
2
1
5
TOTAL
7
itO
73
79
(d) Percentage Kaolin + Mica
TABLE 6.15 Contd.
'
PMF
F
M
Mean age
70.1
69.
71.6
No. of cases
27
80
7*
5o of cases showing
££&
DO/'"
71/o
8&
(18)
(No. of cf>ses)
. (65)
(57)
Mean BHs - all cases
3.0
M
5
Mean BH2 - cases with
emphysema
*+.9
5.9
5.8
PHa range
0-10
0-2 1(
0-22
Mean dust content - cases
with emphysema
(SEK)
6.3 gms
12.3 cms
20.1 gms
TABLE 6.16
(0.8)
(1.0)
(1.5)
Smokers in the 66 - 75 age group divided by pathology grading.
106.
~^\^ Total
< 5 RMS 5 < 10 1CK15 15<20 20<30 30<40 4o<50
BK/^\
^50
Total
< 1
9
10
10
5
6
1
0
0
41
1 <5
9
12
14
11
13
6
2
2
69
5 < 10
6
17
12
6
2
5
0
0
48
10 < 15
2
3
5
3
2
1
C
0
16
»15
1
3
1
1
1
0
0
0
7
27
^5
42
26
24
13
2
2
181
Total
\^ Total
^^Coal
BH?
^-
< 4 gms
4 < 8 8 < 12 12<16
16<20 ! 20<24
2*K28 28<36 ^36 Total
!
< 1
15
15
5
5
1
0
0
0
0
*t1
1 <5
14
22
10
10
It
2
2
2
3
69 '
5 < 10
16
16
7
3
0
k
1
1
0
i»8
10 < 15
6
4
3
1
0
2
0
0
0
16
=»15
3
1
1
1
0
1
0
0
0
7
5^
58
26
20
5
9
3
3
3
181
1Q<-|li
1^:18
£18
Total
^
-5
~ ^r,'-'-
6 < 8 8 < 10
.
2 < ')
'! < 6
12
13
3
2
it
3
3
1
41
1 <5
12
17
10
11
6
it
6
3
69
5 < 10
11
15
12
5
3
1
0
1
48
10 < 15
3
3
5
1
2
1
1
0
16
>15
1
it
2
0
0
0
0
0
7
39
52
32
19
15
9
10
5
181
^~\
A r-1-
-\nSll
BH?
< 1
Total
^\ .
Total
TABLE 6.1?
The relationship between the mass of the different lunp dust components
and levels of emphysema in 181 men from the Pneumoconiosis Field
Research Study.
These men were all smokers in the 66 - 75 age group.
10?.
\^
Total
< 0.5 gm
0.5 < 1 1 < 1.5 1.5 < 2 2 < 3 3«< 2^ Total
B
<
1B^^
21
7
3
4
1
5
0
41
1 <5
20
23
9
7
6
3
1
69
5 < 10
19
1?
9
1
1
0
1
48
10 < 15
5
5
*»
0
1
1
0
16
>15
3
4
0
0
0
0
0
7
65
56
25
12
9
9
2
181
Total
-^.
Total
^\IC
+ M < 1 pra 1 < 2 2 < 3 3 < 5 5 < 7 7 < 9 9 < 11 > 11 Total
BH3
^^-\
10
10
5
k
5
3
3
1
41
1 <5
9
13
10
T+
11
3
5
if
69
5 < 10
5
13
12
12
5
0
0
1
48
10 < 15
2
2
i*
i»
2
1
1
0
16
5-15
1
0
4
2
0
0
0
0
7
Total
27
38
35
36
23
7
9
6
181
< 1
TABLE 6.17 Contd.
108.
^\
«* **
25<55
<**
<1
1
K 5
0
5OO
2
10<15
1
3
2
W>
0
0
6
10
It
55<65
65<75
75<»5
85<95
^95
TOTAL
7
10
0
It1
12
0
11
1?
9
69
it#
16
7
9
3
9
10
2
2
2
't
2
3
5
1
1
2
0
1
1
3
0
0
'U
_T1_L
7
11
5
3
4JLJL2 I »
<!??'
<1
2CK28
8
8
6
1
K 5
5<io
•
1<X15
>15
3
1
0
5
1
0
2
\*2
0
28C3" 36<U'4 V-K52
52<6o
60<6S
63<76
£76
TOTAL
2
3
5
6
in
0
r-9
10
6
it
2
1
2
3
2
1
1
0
0
1
3
7
3
1
1
1
6
7
11
0
0
itS
16
7
20
oc;
' ~s
1?
15
"o
7.
10<12
12<Ht
1*16
It
it
8
i
5
13
4
it
1
13
11
2
2
24
5
TOTAL
BHs
12010
I
0
?7
5*f
<2t
2<4
K6
6<8
8<10
3
it
10
7
11
6
10
3
5
2
1^
181
*16
TOTAL
3
1
It1
0
0
69
i
i*K
0
16
^v
< 1
K 5
500
t
23
:
0
11't
>15
0
't
TOTAL •
8
56
1CK15
TABLE 6.18
t/
7
/i
1
2
8
s
1
1 •
0
1
0
1
0
0
7
26
16
18
16
8
2
181
31
L:
2
3
2
The relationship between the percentage composition of lung dust
and levels of emphysema in 181 men from the Pneumoconiosis Field
Research Study.
These men were all smokers in the 66 - 75 age
group.
109.
I
\#
K+ M
^\
< 5$
BH?
^-,.
i
5 < 10 1CK15 15<20 2CX25
< 1
0 3
1 <5
0
k
'•
8
k
10
Ik
5
10
I
I
25<30
30<35
35<^0
7
-,
6
8
C
I
'
'tO<'»5
<45<5C
5
2
0
M
5
8
3
2
69
i
5-50
Total
5 < 10
0
1
?
10
5
10
6
1
2 •
5
1
^8
10 < 15
0
0
it
3
0
2
2
2
0
3
0
16
»15
0
0
1
3
0
1
0
0
1
1
0
7
Total
0
8
30
»
20
28
Tt
Tf
16
11.
3
181
TABLE 6.18 Contd.
110.
\^
^*^\-
Jw.phvsetiia
PIT
I
~^/"'
Total
i
:
:
j
'
I
< 150
| 1 i 1
0
1
i 0
150 < 300
j 2
3
3
2
2
300 < it 50
7
q
^
*
;
"\^^
! 2
Miphyseroa
^ ^ ^Rn" s
^^^^^
t
2
;
|
i 1
!
Total
0
, 1
57
!
200 < 300
i
0
| £ 300
2
:
"•-
1<5 5<10
Ernrhysema
û
*^
^^~,^
1CK15
< 50
1
1
0
2
1
50 < 100
it
3
2
1
0
100 < 150
3
£ 150
it
8
3
it
4
2
0
-^-«
• n
Y
_ <6
j
1CK15
£15
0
1
0
3
3
2
3
0
/4
2
12 < 18
I
-$. 18
^
1CK15
515
Total
^\^
K H- M trh/ffl 3
^-,
< 25
1
0
0
1
0
2S < 50
it
9
it
5
1
50 < 75
3
2
2
1
• 0
2 75
<4
it
2
0
1
1
i
0
10<15 £15
1
i 3
2
0
3 I ^
I
_
6 | 1
2
1
_
I
j
'— —
1
The relationship between exposure to mine dust and its constituents and
levels of emphysema for it*1 men.
The figures are based on individual
exposure records.
Units are gram hours per nr3 .
I
2
5
.
~
'•'
| 0
1
2
6< 12
<1 | 1<5 5<10
5<10
i
i
1<5 : 5<10
I
j
<1
S
!
k
Total
""\
O.uartz Rh/rri3 ^^^
Total ^^-^^
Ash pln/ni3
^^^.,.
TABIE 6.19
1<5
<1
\^
< 100
T
<1
UH_
^\
100 < 200
:
0
Mrar.vr.cnia ;
~\
I
:
£ ^50
|"\
1<5 ! TK10 : 1C<15 ' £15!
! <1
'\^
;
.
0
-
111.
Emphysema
5<10
Emphysema
1CK15
% Coal
% Ash
60 <
30
5<10
215
1.
"~-\^^ Emphysema
. ^^gHj,
% Quartz
^^^~~--^
Emphysema
<1 1<5 5<10
1005
515
10<15
< 3^
3
1
3
2
c
3 < 6£
7 13
5
5
2
10 < 20^5
6 < 95^
2
1
0
0
0
20 <
> 9^
0
0
•
0
0
0
TABLE 6.20
12
2
1
0
0
The relationship between'the percentage composition of mine dust and levels
of emphysema for kk men.
The figures are based on individual exposure
records.
112.
Coe fficient
Term
Standard error
Constant
U)
-7.57
1.35
Additional constant if smoker
(a,)
2.56
0.79
Lung dust weight if smoker
(aa)
0.05
0.01
Lung dust weight if non-smoker
(83)
0.12
0.04
Age
vai )
u.uo
U.I*
TABLE 6.?1 Estimated coefficients for the model utilising lung
dust data.
Coefficient
Term
Standard error
(to)
-4.002
2.625
Additional constant if smoker
(bx)
2.252
1.365
Dust exposure if smoker
(ba)
0.002
0.002
Dust exposure if non-smoker
(b,)
0.005
0.004
(b4)
0.032
0.033
Constant
Age
1
«
TABLE 6.22 Estimated coefficients for the model utilising dust
exposure data.
113.
DISCUSSION
Relationship between lung and dust content and pneumoconiosis
found at autopsy in British coalminers has already been the subject
of a number of studies including those by KING and NAGELSCHMIDT
KING, MAGUIRE and NAGELSCHMIDT (1956); FAULDS, KING and NAGELSCHMIDT
(1959) and SPINK and NAGELSCHMIDT (1963). However, previous studies
have mostly dealt with cases from a single mining area on each
occasion and relatively little information has been obtained on dust
and disease variations over the whole country.
nVDCWAMM
...
„„,)
....
/"•ACCWTTTT
.
v.«-^v,4-«,J
- ~ i- —
*~
~~
ov,~-|, rc--i
••-•••~j
o
In 1972, 'however,
~-T 1
— -—(.J
,«..o<.
-"
<?>.„-.
-•
^
series of cases that were drawn from ail the British mining areas.
Little pathological information was available but it was shown that the
composition of lung dust found in cases from any area varied
considerably with the rank of coal nrined.
For high rank collieries
the percentage of ash in the lung dust was low but in low rank areas
the percentage of ash and its constituent, quartz, was much higher.
The present study has been able to examine cases from all British,
coalfields.
Since cases were obtained mainly from the Pneumoconiosis
Medical Panels it is likely that the population under study was biased
towards men with severe disease.
However, for the first time in Britain it has been possible to
examine the way in which pneumoconiosis may vary depending on the type
of dust inhaled.
It was found that even in men with roughly similar
types of pneurncooniotic lesion, the lung dust rnrxrs and composition
could vary considerably.
For any dust analysis the ranges found
within one pathology type could overlap the other two.
When the mean
figures were considered, however, some definite trends were apparent.
The mean levels of total lung dust and all. its constituents were shown
to increase between cases with macules, fibrotic nodules or PMF for the
whole group under study.
There were, however, considerable
variations
in the level of increase when the cases were divided into groups
depending on the rank of coal mined in the collieries v/here the men
worked.
Variations in the level of dust were also found when cases
v/ere grouped according to geographical area.
Firstly, it was found
that while cases within either the soft macule or fibrotic nodule group
hnd relatively similar levels of dust regardless of rank, those with
PMF showed a reduction of lung dust between the high rank collieries of
Group 1 and all other collieries.
This was even more marked when the
coal content of lung dust was considered and, as may be expected, the
reverse was true when the ash content of the dust.and its main
components, quart?,, kaolin nnd rrdca, were exarr.i.Tied.
Since the dust from collieries producing low rank coal is known
to have a high ash content it was not surprising to find high
percentages of non-coal minerals in the lung dust from men who had
worked in this type of colliery.
However, of potentially much greater
importance was the finding that the composition of lung dost varied with
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highest rank collieries (Group 1), there appeared to be no difference in
lung dust composition between the three pathological types of
pneumoconiosis and there was little change in Group 2.
However, in the
low rank groups there were progressive decreases in the mean coal
percentages and, conversely, increases in the ash and its individual
constituents between cases with only soft dust macules, those with
small, hard fibrotic nodules and those with PMF.
These findings are in agreement with the reports of KING, MAGUIRE
and NAGELSCEKIDT (1956) and SPINK and NAGELSCHMIDT (1963).
The former
paper reported that there was no increase in quartz percentage between
different levels of pnfmmoconiosis, but all their cases" came fro.n
relatively high rank collieries that would correspond to our rank groups
1 and 2.
SPINK and NAGELSCHMIDT reported, however, that in coalminers
•i*iv»n! C"i;"iVif:T"! STIC! there V7C.C co~c evidence cf ' s.r, -;T'y"sQS'' *"* ^"'^^^^
percentage with increasing levels of pneumoconiosis.
For the most part
the Cumberland coalfield mines medium rank coal.
From all this information it seems likely that either some cases
with progressive massive fibrosis have been exposed to dusts of
different composition to others or that the lung dust composition has
changed during the course of disease development.
A comparison between
the compositions of the dust to which individual cases were exposed and
lung dust levels indicates that the latter suggestion is correct.
In
high rank collieries there has been nc change between mine dust and lung
dust composition but in low rank pits there appears to have been a
progressive differential accumulation of the ash components between the
three pathology types with the quartz composition of PMF cases
especially being as much as three times higher than in the original mine
dust.
115.
This situation is, however, a. little complicated by the fact that
the only ash components for which a specific analysis has so far been
made in the lump; dusts, quart?, and kaolin and mica, account for on
average 8($ of the ash in lung dust but only 65% of the ash in mine
dust.
Those differences were greatest in the low rank areas.
This
means that some ash components (for example, calcium, magnesium and
iron salts) are being lost from the lung tissue either during the
extraction procedure or during life.
However, if the only loss
occurring was during dust extraction the effect would be a reduction in
thff
•nemPnt.Aifr>
ash
found
in
thp
I n n r dust: nf
nmr <-n.c:o w-i -Hi «
corresponding increase in coal percentage.
That this is not the case
is shown in Chapter 1, Figure 19« Similarly there would be no
compositional differences between the pathology grades.
It appears
therefore that the presence of PMF in men who worked in collieries
mining low rank coal is associated with the finding of a relatively higher
proportion of quartz and kaolin and mica than was estimated to have been
present in the original mine dust.
More detailed studies of these
findings are in progress wMch involve the division of cases with either
fibrotic nodules or PMF into more defined groups depending on size, type
and number of lesions.
It is important to consider whether or not the increased levels of
quartz and kaolin and mica found in cases with either fibrotic nodules
or PMF from low rank collieries are directly related to the development
of th*Kfi 1 psior>Rj
TViis is especially important ir. the cs-sa cf quarts
since pure quartz is known to produce a severe form of nodular
pneumoconiosis (silicosis) and it was believed for many years that
coalworkers1
pneumoconiosis was merely a modified form of this
silicosis.
In 19^0, however, GOUGH reported that coal trimmers working
with pure coal in the holds of ships developed severe coalworkers'
pneumoconiosis although the dust they had inhaled contained negligible
quartz.
In some countries, coalworkers' pneumoconiosis is still called
silicosis and a quartz standard is used in monitoring levels of mine
dust.
In Britain, for many years dust control in coal mines has used
an overall dust standard.
In drivages, where the quartz level in the
dust is taken into account, a lower overall level than on faces is applied.
Ar. already stated, evidence has now been produced that all three of
the ash components, quartz and kaolin plus mica, are not only present in
higher percentages in established PMF cases from collieries mining low
116.
rank coal than in individuals without this severe form of pnoumoconiosi.s
hut are also -present in a higher percer.tage than in the original mine
dust.
In addition FKF cases from collieries mining low rank coal have
si crni f icantly lower trie an levels of total lung dust than those cases from
high rank collieries.
These findings indicate that the accumulation of
dust containing a high percentage of non-coal minerals in the lungs of
coalrniners working in collieries mining low rank coals other than the
overall mass of dur.t is associated with the presence of PMF.
The
results fron the present study, however, show that the non-coal minerals,
quart?,, kaolin and mica, are present in all cases of PMF at very sir.ilr.ir
relative proportions regardless of the total lung dust mass.
There is
thus no direct evidence that quart?, is the particular ash component
associated with the development of the massive lesions.
At the same
time, however, no evidence has been produced that this is not the case.
The present study has produced no data to show whether the non-coal
minerals act directly in the production of PMF or as an intermediate
factor, perhaps making the lung tissue more susceptible to infections
such as tuberculosis.
In this connection it is unfortunate that all
the lung material used in the present study was received after prolonged
formalin fixation r^r.rt no bacteriological studies were possible.
Only
seven out of 5^0 cases hnd tuberculous lesions recognisable
histolcgically.
Similarly no data were available on variations in
individual susceptibility among the 500 cases.
These variations might
be important in determining the rate of differential lung clearance, the
severity of tiss::n reactions to any given dust, or the occurrence of
some form of autoimmunity in response to reactions between dust particles
and tissues.
The results from the present study and previously published work by
other authors suggests that there is no single cause of progressive
massive fibrcr-;is.
Consideration of all the available information
makes it possible to suggest the following causes of PMF in collieries
mining different ranks of coal.
In high rank collieries, where the ash
content of mine dust is low it is possible to build up considerable lung
dust levels.
In these cases the dust mass itself may eventually be
sufficient to cause the development of massive lesions although
infection and individual factors may be i nvolved,
However, some miners
from high rank collieries develop massive lesions although their lung
dust burden is relatively low.
In these cases it is very likely that
infection or autoimmunity has played a decisive part.
In collieries
117.
mining low rank coal the accumulation of lung dust with a
percentage of non-coal minerals may be sufficient on its own to cause
the development of massive lesions at low total dust levels or it may
predispose the tissue to infection or an autoimmune reaction.
Chest radiographs form the main diagnostic procedure in esses of
pneumoconiosis but so far relatively little work has been done on
correlating radiographic shadows with definite lesions in lung tissue
and the lung dust content.
ROSSITER (1972) compared dust contents
and radiographic category in J22 coalminers but he had no pathological
IT/DEI! c c l . (1970) ar
levels of pathology with radiographic category but had no duct data
available.
The present study with 259 cases for which pathological
data, lung dust fig'ures and recent chest radiographs v/ere available has
allowed further examination of the inter-relationship of these factors.
It was found that some cases from the group recorded as having
fibrotic nodules were classified radiographic ally as 0/0.
However,
to be included in the F pathology category, cases needed only one hard
fibrotic nodule of one millimetre in diameter.
Later studies with this
material will subdivide the F group according to the number and size of
the fibrotic nodules, when it would be expected that those classified as
0/0 by radiograph will be found to have very small numbers of these
lesions.
The number of dust foci present in the lung tissue correlated
reasonably well with the radiographic profusion of small rounded opacities
(correlation coefficient 0.^5) but some cases recorded as 0/0 nonetheless
had foci counts in the highest rangec
The potential number of dust
deposits depends on the number of suitable anatomical sites near
respiratory bronchioles and it appears that these could all become
pigmented with dust relatively early in the course of exposure.
Increasing radiographic category may therefore subsequently depend not
on an increase in the number of dust deposits in the lung tissue but an
increase in those sufficiently dense to produce recognisable opacities.
In the cases examined in the present study those with the smallest or
p type of opacity were more likely to have the highest recorded numbers
of dust foci than those classified as q or r.
11?,.
This indicates that either some of the q or r opacities ore
produced by the fusion of small dust deposits or the pathogenesis of
the various nodular types is completely different.
V.'hilo it wan knovm that there is considerahle inter-reader variation
in the categorisation of simple pnenmoconiosis by chest radiographs it was
found in the present study that fibrotic lesions measuring more than 1 cm
are not always recognised as progressive massive fibrosis on radiographs.
Twenty-one out. of ^9 cases with lesions found at autopsy to be between 1
and 5 cm in diameter were not categorised as PMF by any of the four
itOMtiO.
i l u w c vr:j. ,
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some anatomical peculiarity such as cavitation or close proximity to a
fissure.
Whether these factors were associated with a poor radiographic
image has not yet been studied.
\
The present study has confirmed the findings of ROCSITER (1972) that
there is in genera] a good correlation between overall lung dust content
and the radiographic profusion category in pneumoconiosis cases.
However,
at this stage in the present study, no attempt has been made to examine the
effects of the mass absorption coefficient.
The finding that cases with q
or r type opacities tend to have lower levels of lung dust than those
graded p may be associated with ROSSITKR's observation that the radiogranhic d.e*"!si t"1' of "nodul&r sized opacities" v.ra.s often, greater tl'.ari would
have been expected from the mass absorption coefficients of the dust they
contained and that "the nodularity may be some response to dust other
thar. simple accumulation".
In cur sturty, hnwRVfir. a corr>pr;ri.?on of raclio-
graphic category and lung dust content suggests that while the mass of all
dust components has tended to rise with increasing category of simple
pneumoconiosis, cases with either category A or B PMF actually had less
dust :in their lungs than cases with category 2 or 3 simple pneumoconiosis
and the differences between the PMF cases and cases v/ith category 1 simple
pneumoconiosis were relatively small.
Similarly, while there were narked
compositional changes between categories 0 and 1, there were almost no
differences betv;een categories 1, 2 and 3 and PMF for the percentage
composition of either coal, ash or kaolin and mica.
Thi£ contrasts with
the findings from comparisons of lung dust composition in cases divided
by pathological examination as having either macules, fibrotic nodules or
FK;F (Table 6, Appendix 1).
For the most part, however, these differences are more apparent than
real.
Since many cases with fibrotic nodules were classified by
119.
chest radiographs as category 0, the category 0 dust figures have
become higher than the rancule group in the pathology study.
For
similar reasons the figures for category 1 prieumoconiosis are higher
than the pathology group with fibrotic nodules since it will probably
have been those with fewest fibrotic nodules and hence the lowest
dust that were included in the category 0 group.
However, an
examination of the two methods of classifying cases
for lung dust content has probably revealed two important factors.
When cases were divided by pathological type, the mean values for
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classification, however, indicated that cases graded category 2 and 3
appear to have more total dust and all its components than the overall
group of cases with PMF. Only 1^ cases are involved but unless
these are quite atypical it may mean that men who reach these
categories yet do not develop I-T:F before death are those whose
biological reaction to the dust is relatively low and who are thus
able to build up high lung dust levels without developing massive
lesions.
The second point stems from the fact that while there are
compositional differences between the pathological gradings of H, F
and PMF and between radiographic categories 0 and 1, there appeared to
be no clear trend in compositional differences between radiographic
categories 1, 2, 3 or PMF.
If, as has been assumed, this is because
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raised above those for the fibrotic nodule group by the classification
of many cases with fibrotic nodules as category 0, then it indicates
that the compositional changes noted between the three pathological
types are occurring largely during the development of the fibrotic
nodules and before the development of PMF.
This concept is supported
by the finding of compositional changes in lung dust between cases with
p type radiographic opacities and those with q or r but little
difference between the q or r types themselves.
This matter will be
explored further in later studies using the same lung material when it
is proposed to divide cases with either fibrotic nodules or PMF into
subgroupings depending on the size and histological type of the lesions
involved.
Examination of the lung dust composition for '490 cases divided by
120.
coal rank suggested that differences between pathological types' were
only evident in rank groups '* to 6.
When the ?59 car.es with, chest
radiographs were similarly divided for some categories the numbers
achieved wero small (Table 5.15).
Nevertheless there was an
indication that the compositional difference between categories 0 and
1 noted for all such cases was mainly a feature of those from the
lower rank groups.
Confirmation of this finding would substantiate
the hypothesis that compositional change is related to the development
of pr.euir.cconiotic disease in cases from these areas.
the Brian Heard method were compared to radiograph readings, lung
dust content and dust exposure where suitable- data were available.
From these studies a number of interesting points have emerged.
There
appeared to be little relationship between the emphysema levels and the
overall profusion categories of X-ray readings for small rounded
opacities.
However, LYONS et al. (197*0 suggested that the presence of
small irregular opacities was associated with emphysema and the present
study has confirmed this general finding.
In addition it was found that cases with the p type of small
rounded opacity appear more frequently associated with high levels of
emphysema than those with q or r tyt>e opacities.
This observation has
already been reported by RYDER ejt_ _a]_. (1970) and it is hoped that more
data on this association will become available when detailed
present study.
•
As expected from previous reports, age and smoking habit were
found to be associated with the development of emphysema in the present
^50 cases.
In addition to this, however, the presence of severe
pneumoconiosis was an important added factor.
Thus, of 181 smokers
aged between 66 and 75 only 66?b of those with soft dust macules had
emphysema as compared to 88?o of those with PMF.
The mean levels of
emphysema also increased in this group with the increasing severity of
pneumoconiosis.
Preliminary statistical investigation of data from
all the cases in this study indicated that while smokers had a higher
likelihood of developing emphysema because of their smoking habit,
after this fact had been taken into account, the lung cuot content
contributed more to emphysema levels in non-smokers than smokers.
121.
This rngy mean no more than that smoking and dust act in combination
and not as additive factors.
It is unfortunate that very few cases
from the present study were non-smokers with high dust levels so that
no reasonable extrapolation of the analysis may be made at these
levels.
In considering dust and emphysema relationships, however, it must
be remembered that the present report only covers the estimation of
overall emphysema.
Analyses of results considering the different
types of emphysema as separate entities are stil] in progress and will
ue
Icrfjui'^tru
Oil
CAI.. a
Xdcci
v^cicc.
r:uo L w u i r\ c t i_» w t i u
nt^vo
i u f / W i ni ^t
un
the association between coalworkers' pneumoconiosis and emphysema
(HEPPLESTON, 19?2) have talked specifically of centriacinar or
circumscribed emphysema and it may be that when figures for this form
of air space enlargement are available for the present group of cases,
any association with lung dust content will be clarified.
In this
connection it must be remembered that centriacinar emphysema is a
common finding in the normal population.
A susceptibility to develop
this condition may be aggravated by the prese-nce of coal dust but the
overall, level of emphysema need not correspond to the actual lung dust
levels.
In conclusion it. .should be appreciated that much of the work
renorted here is part of on-going studies.
Certain limitations upon
case selection and examination are inherent in the structure of the
study.
Nevertheless, hypotheses which are irmorporafcsjti in '.his
preliminary examination of data may be subjected to further
•
statistical examination and the pathological approach may be refined
by a more precise division of cases based upon detailed estimations
of dust deposition.
In addition it will be possible to approach
questions which arise from this work by a selection of cases
appropriate to each specific question.
Clearly the data already
available may be examined from a number of starting points and any
conclusions drawn are reported with this in mind.
123.
ACKNOWLEDGEMENTS
The authors wish to acknowledge the important contribution made
to this project by the staff of the British Pneurr.oconiosis Medical
Panels and by staff from the Pathology departments of Ashinpton
Hospital, Northumberland, Ballochmyle Hospital,Ayrshire, Burnley
General Hospital, the Coventry and Warwickshire Hospital,
Sunderland General Hospital, and the West Cumberland Hospital who also
provided some of the lung material examined in this study.
The authors would also like to thank Dr» J.GS Bennett,
Dr. J. Burns, Dr. J.A. Dick, Dr. D.J. Thomas and Dr. J.S. V/ashinn;ton
for reading the X-rays reported on in the present study, Kr. D. Brown,
Kiss B. Calder, Kr. A. KcDowall, Krs. K. Niven, Kr. R. Porteous and
Kr. H.E. Tully for their skilled technical assistance and Krs. A. Darby
for her organisation of computer programming.
AKDSRSCN, J.A., DUNNILL, M.S. and RYDER, R.C. (197?.)
Dependence of
the incidence of emphysema or. smoking history, aê and sex.
Thorax 27, 5'*7
-551.
BEIT, T.Ii. and FERRIS, A. A. (19(<2)
Chronic pulmonary disease in
South Wales coalminers - I. Medical Studies, C. Pathological
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Special Report Series Mo. 2^3, 203 - 222, Medical
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BERGMAN, I. and CASSWELL, C. (1972)
Lun/s dust and lun^ iron
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Br. J. ind. Med., 29, 160 - 168.
C APIAN, A. (1962)
Correlation of radiological category with Inn;*
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1
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Further studies
In:
l i a n d b u c h der
PneunoV.oniosen, p.101
( E d i t e d W . T . Ulrnei-
and G. R e i c h e l ) , B e r l i n , Sprinprer-Verlag.
LAW!NEC, R . T . H .
LK BOUFFAI-JT, I..,
Traitc de I 1 a u s c u l t a t i o n m e d i a t e ^*_, Paris
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(1977)
1819.
Quarts as a
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Industrial health
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I.?I:JT;-;PITZ, I!., B A U E R , D. and B W ' C K K A K N , K. (1Q71)
Minernlorricnl
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In:
;
Inhaled' P a r t i c l e s 111 (Edited. W . H . V / a l t o n ) , 72^ - 7^ i, Unwin Bros.
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Significance of i r r e p u l a r opacities in the radiology of coal workers'
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Br. J. i n d . M e d . _3_1_, .36 -
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Block pht.isisis, or u l c u r a t i on i n d u c e t i by
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rned. Sci.
^
6^5 - 653.
MARSHALL, V,'. (1^33 - 183^ a)
Cases of spurious melanosis of the lungs
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lungs.
Konthly'J.
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Lancet II,
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Remarks on snurious m e l n n c s i s of the
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Coal workers'
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350 -
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128.
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Br. J, ir.d,, Ked. V%
JO - '*?.
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Duat
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Br. J. ind. Kcd. T?, R? - 10R.
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K^tional Coal Bonrd's
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In:
Inhaled
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C
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Dent Klin. _12_, ^75 and t»8?.
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Relationships between
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The
1
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Inhaled
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Dent. Arch. Klin. Med. 2_, 116.
131.
APPENDIX A
Mean figures for lung dust weights and percentage composition
divided by pathological type, colliery, coal rank group and
geographical area together with statistical comparisons.
132.
1
Colliery
Identification
i-,:tho~\ curie »\
Type
•
r
M
l'f\T
Mean v e i r h t s of riinpra.'.s riresont
i: -'.can c e r c n n t i i R e corarjosi tiou
Kupber i
in b o t h li-r.~3 (-.-.)
!
of ciur-t in 3\i:irs
,,
%.
' Kaolin
•a K a o l i n
in
v
£!/
Dust
Nonnnd
Group
Coal
Quertz. j ar.ri
Coal
Coal
^nrt.
Con 1 .
.
^
?.
19.25
••.
iYI
39.76
'1.32
17. '19
6.8
2C *»
36.A2
3.^
O.'t'+l
2.5';
91.7
8.3
1.13
6.1
2.97
7 . ;o
5-07
'} . 7 f/
1.'=?
0.165
0.8*4
T
63.7 36.5
;
::
''.55
C
2.3.0
3.20
0.7--L'
O.ôil
61.5 30.5
5.73
25-9
1.^6
56.1 *t3.9 6.62
i.5 p - ! ; 62.6 37. '4 5.65
*4.37 ii*42.3
57.7 9.78
I
0.1*15 1.8*4 I63.5 36.5 5.22
0.59't | 2.1'* I 55.1* ' 't'i.7 6.92
29. *4 70.6 11.83
1.279
't.65
26.8
23.1
*tC.9
0.273 ! 0.91
';;'.7''
3
'?.27
M
F
K-!F
8
8
7
7.10
6.18
11.0'+
D
M
F
PMF
5
1+
1
5. so
6.63
10.81
3.07
3.18
3.07
3.62
7.63
M
F
PMF
5
E
6. ft 't.71
10.80
&'.°£
3'i.8't 30.28
1.95
1.82
'4.56
0.22'i
0.606
6.53
19.66
25.61
1.16
<(.17
5.*40
0. 5;*'f
0.806
C
F
„
F
. PMF
1*4
5
6
17
20
1+.56
3.73
14.87
2.*4*
5.37
15. ^9
20.21
_
M
1.99
f 2-''
1.75
•1
3
12.3
r.o - ' l,f "
ilT
H
F
FI'F
E
87.6
- -.-,{; ] f\ r,-^ I •) po
C.
_
2.53
2. '45
6.16
_
. 9 ' t 'j ^7.9
'\ '~>
?
' 2.1
,. 0
0.373
0.385
1.030
0.223
0.131
';0.9
2*4.6
27.8
143.0
1.53
1.28
3.9'1
72. '4
27-7
82.6 J 17. 'i
81. i* 18.6
3.2''
2.31*
2.73
21.5
0.76
2.77
3.95
82.9 17.1
75-5 ? - l --5
77.2 2.2.8
_
2.16
3.-0
3-52
9.82
16.0
16.9
_
_
_
13.0
15.5
„
0
2
7
6.77
11.91
3.01
3.5*t
3.77
8.37
o.6'49
1.87*4
1.88
5. 1't
**6.7 53-3
3L9 68.1
9.70
15.2
M
F
PH?
11
1(4
*4.58
9.3't
'..i+O
7J>5
1.17
1.89
0.167
C.86
0.270
1.M*
3.o8
3.10
0.91C
I,
77.8 22.2
73. *4 21.6
?1..7 28.3
I
H
F
PMF
5
19
11
0.91
2.07
2.97
0.1 ;>6
0.318
0.511
o.tSu
1.57
2.18
77. 'I
76.0
78.7
22.8
2*1.0
21.3
5.6'+
3.66
3.6'+
H .
F
PKF
2
2
0
3.31
3.87
-
1.97
2.07
-
1.35
1.79
-
0.196
0.303
-
0.723 58.2
1.01
5^.6
-
M.8
6.13
7.37
-
22.14
J
M
F
PMF
2
15.51
15.33
6.80
8.71
10.92
6. 8't 17.56
0.61*1
1.9C5
3.091
'4. 91*
5*4.1
't.i+2
27.2
6.£'i
11.2*4
29.8
30.1
70.1
69.9
12.06
12.21
M4.8
M
F
PMF
5
9
6
3.73 3.99
'+.'43 7.56
6.82 11. '*?
0.71*4
2.10
1.351
'4.89
52.3
37.5
37.2
*'7.7
62.5
62.8
8.57
11. '-6
11. ''2
2.8.6
'40.2
'•1.5
G
H
K
L
TABLE A.1
F
PriF
„
* r~(
5
6
*• "
"*r
't. 63 3.71
11. 7^' 9.66
15.69 12.72
2*4. *40
7.73
11. Q8
10.30
'i.'fO
2.r:78
Cl.
7.52
'tS.'t
-
'45.9
L Ac;
26.0
*42.2
15.6
16.5
? ? ;5
1*4.9
17. *4
15.1
25.0
-
*43.*4
Mean fif>;u:-'j.i for ]un!^ dust w e i g h t s and p e r c e n t a g e c o m p o s i t i o n for the three
pathological types of p n e u m o c o r a o s i n in each of the 25 c o l l i e r i e s of the
iosit, Kj.olfl Rasearcli s t u d y .
133.
Colliery
Identification
Fathologiecl
Tyre
Mean weights of minerals present
Mean
Number
in both lungs (gm)
in
Kaolin
Group Dust Coal Nonand
Quartz
Coal
Coal
Mica
M
M
F
PMF
4
7
11
N
M
F.
PMF
0
9
0
P
_
3.45
5.79
9.33
_
0.452
1.023
1.540
2.34
3.90
6.50
'
4.99
8.31
9.25
22.7
33.1
37.6
_
41.8 8.31
**9.9 50.1 10.01
29.0
25.7
16.6
6
.
4.13
8.16
M
F
PMF
1
5
6
3.02
16.12
17.84
1.69
12.51
10.55
1.33
3.61
7.29
0.225
0.616
1.257
0.78
2.1?
4.74
55.9 44.1
74.2 25.8
55.9 44.1
7.43
4.38
7.78
29.7
M
F
PMF
1
3
4
10.32
13.36
14.67
6.57
7.90
8.28
3.75
5.^5
6.39
0.475
0.961
1.504
3.65
3.85
1.92
63.7 36.3
58.4 41.5
53.2
46.8
4.61
7.90
11.6
18.6
26.2
27.1
1
3.14
13.54
13.72
2.02
6.03
3.22
1.11
7.51
10.50
0.18S
1.428
1.921
0.867 64.5
5-38 44.7
35.5
7.37
55.3
28.0 72.O
5.89
10.60
13.66
27.7
38.6
50.5
6.31
18.83
13.15
4.58
11.11
6.52
1.72
7.73
6.64
0.290
1.228
0.786
0.98
5-07
4.51
73.0
69-4
48.0
26.8
30.6
52.0
4.72
4.95
8.17
15.00
20.9
31.7
PMF
7
16
26
7.42
5.70
21.74 16.05
20.05 14.37
1.72
5.69
5.68
0.312
0.997
1.050
1.06
3.85
3.9^
76.7
72.1
68.5
23.3
27.9
31.5
^.31
5.00
6.22
13.6
18.9
21.6
M
F
?HF
1
2
18.80 15.39
9.09 6.99
20. PC •15.39
3.41
2.10
'.'.•'.,'
0.438
0.252
2.82
1.64
18.1
15.0
18.8
U.VJJU
23.5
2.33
2.81
5.'-'.?
81.9
76.5
30. f
•f.VD
t'\.3
5.24
9.19
16.38
3.18
5.19
1.55
0.211
0.488
0.804
1.00
2.30
3.47
70.0 30.0
64.5 35.5
65.4 34.6
4.10
5.60
5.42
24.8
22.0
3.86 0.619
4.4?
14.24 11.95
2.29
40.4? 34.60' 5.87
0.105
0.384
0.972
0.41
1.83
4.74
84.6
79.6
77.3
2.69
3.49
3.62
10.1
16.1
18.3
6.36
2.421
1.9^2
2.138
8.93
6.71
6.68
29.7 70.2 11.31
32.2 67.8 13.85
30.5 69.5 13.79
47.0
42.9
PMF
T
F
M
....
M
F
4
3
6
2
5
~
17
PMF
25
15
w
M
F
PMF
6
7
6
X
M
F.
PMF
1
11
12
Y
M
F
PMF
0
9
11
21.40
13.80
15.20
3.69
6.01
11.19
4.22
4.49
15-01
9.58
10.70
_
—
^
6.88
10.79
22.44 14.41
—
3.90
8.03
—
0.656
1.247
_
Z
62.0 38.0
51.6 48.4
*»5.5 55.0
_
1.150
2.324
M
F
PMF
V
5.69
7.83
8.04 5.83
10.15 11.47
s
U
5.51
13.89
21.63
M
F
Q
8.96
11.49
17.16
_
percentage composition
of dust in lungs •
% Kaolin
%
Nonand
Coal Quartz Mica
M
F
PMF
TABLE A.1 contd.
0
2
0
—
8.69
~
—
3.58
~
—
58.2
\s S • C
15.6
20.4
22.7
_
"~
0.690
~
41.8
—
—
64.3 35.6
62.7 37.2
5.75
6.07
22.8
21.9
42.9
7.78
28.3
_
_
_
„
—
5.11
18.6
_
—
2.481
4.66
35.^
2.68
™
™
57.1
"
~
™
Fulholoi'icfti ,
v'osl K»«k *iro«n
Overall
(28)
6.3?
9.05
12.78
(18)
(19)
(19)
20.00
(190)
(?1)
9.76
(56)
14.33
(490)
H
S.46
F
11.0.5
(21) I 1}.->6
(50)
14.06
(42)
12.26
(y>)
11.76
(?o)
PMF
37.01
(11) j 22.42
I
(46)
18.00
(44)
10.90
(42)
17.81
16.9}
(43) i 15.S2
(113)
1>.59
(113)
15.96
(PO)
13.50
Overall
(11)
j 5.12
(22)
5.70
14.37
(27)
S? = 92.05
d.f.
(8)
8.50
(14)
7.21
12.51
(100)
(200)
= 472
COAL
Pathol epical !
~
Co<0 Rr>nk (ir
M
4.25
4.01
4.13
10.11
F
9.97
11.03
9.87
32.63
17.49
12.65
6.07
10.29
14.JO
12.24
FHF
Overall
8.43
9.58
Ss = 64.64
4.39
5.65
7.14
I 5.99
4.25
5.48
5.76
4.76
8.22
13.09
5.18
i 9.4O
d . f . = 4?2
ASH
Pathological
Tyoe
WE
'•
M
1.22
F
1.98
1.11
2.73
PMF
5.28
2.63
Overall
Coal Rank GrouD
Vi'3
AMYNX
KFI
K01X3UD2
1.58
1..26
1».11
M3
U.19
5.35
6.18
9."«5
6.11
10.66
3.29
<-.02
7.53
7.5'1
S'= 12.51
!
FCaQJ
Overall
2.12
lt.l»8
2."t5
lt.28
7.02
6.91
ft.58
"••93
d.f. = 1)72
QUARTZ
Patholorical !
Type
j
»<E
HFI
Coal Rank Grout)
VTB
AF.YUX
;
KOLGUD&
FCSQJ
; °verai1
H
0.159
0.152
0.232
0.631
0.542
F
0.277
0.381
1.18?
PHF
0.805
0.769
0.688
0.927
1.69"t
1.0l»5
1.958
0.321
0.776
1.207
0.368
0.725
1.195
Overall
0.382
o.'igo
i 0.672
1.376
1.306
0.776
0.834
d.f.
-
KAOLIN + XICA
Patholorical
Tyre
H
WE
!
1.00
2.63
4.22
3.75
2.93
3.66
2.43
2.75
F
0.92
1.46
0.77
1.94
PKF
4.36
2.07
Overall
Coal RanX Groun
VTB
.
AMY:;X
Hfl
S'- 6.280
KOLGI.'UZ
2.40
S
=
1.26
Overall
3.02
LS't
2.90
6.12
3.79
6.85
4.77
4.74
4.97
4.72
3.05
3.3".
d.f. = 1.72
Hf»n firurea for ]unr dunt wiip'htR found in the three pathological types,
comhined into cix (rrouns by the nnk of co«l mined.
5
rescy
risi'luii verietion.
d . f . = efiBociit*:d dfl^reco of freedom.
Th^se figures wer*; deriTed by n t i n d ^ r d n n a l y n i a of variance techniques.
The collieries are
nanK
Group
COAL
HFI
VTB
AMYNX
KOLGUDZ
Panlr
HFI
VTB
DUST
WE
Coal
Mineral
Component
M»
F*
_
_
_
—
_
AKYNX
K01GUDZ
PCSQJ
_^
HFI
VTB
_
_
_
_
AMYNX
KOLGUDZ
PCSQJ
_
_
_
PW*
M
F
PMF
M
F
PMF
M
F
FMF
M
f
FMF
X
X
_
_
_
_
_
X
X
_
_
_
_
^_
_
_
^__
—
_
_
_
_
_
_
-
-
-
-
-
-
-
-
-
-
X
_
_
_
_
_
_—
_
X
_
_
_
_
~
~
X
X
X
X
X
_
_
„
_
-
_
X
._
-
X
X
X
X
X
X
_
_
_
_
-
-
-
-
-
X
X
-
-
-
-
-
-
_
X
X
_
_
_
X
X
-
-
-
-
-
-
-
_
HFI
NONCOAL
VTB
AMYNX
KOLGUDZ
PCSQJ
-
-
X
X
X
-
.. —.
-
-
-
_
•_
_
_
_
X
X
_
X
X
X
x
X
X
-
-
1
HFI
VTB
QUARTZ
AKYNX
KOLGUDZ
PCSQJ
_
_
_
-
-
TABLE A.3
-
-
—
_•
KFI
KAOLIN
+ KICA
—
VTB
AMYNX
KOLGUDZ
PCSQJ
-
X
-
-
X
X
-
-
-
-
X
-
-
-
-
-
-
X
-
_
_
X
-
Multiple comparisons for differences between mean mineral levels for each coal rank grt-up for each pathological type.
*
Pathological type.
KOTS:
For each mineral component table the confidence that all the statements impliet. in the table are
correct is at least ,9951".
"x" denotes that the difference under consideration was significant
within the overall fpnily of comparisons. Bonferroni t-statistics were used :'or the calculations
within each mineral component table.
All contrasts within the family were compared with equal
confidence.
136.
nur.T
Pathological
.SCL'i'
•
Cinorr.inhic'il Arc.i
1'r', + !:..'
!•' ...'••' of. ' i-'.'l iJ
7.21
(16)
10. '('*
Vt.99
(20)
F
6.97
13.16
(38)
11.81
(5D
5.18
12.13
Pi-iF
16. 01* (1?)
19.75 C<9)
17.3't
C«9)
22.91
12.70 C«2)
16.0-'| (103)
13. Bit (120)
H
Overall
(11)
(TO
Overall .
J.™« ; *
1
6.87
doo)
(53)
(97)
12.71
(200)
(75)
19.96
(190)
Vi.11 (225)
Tt.33
C<90)
S3 = 99.50 d.f. = 1*78
COAL
_ . . , . ,
Pathological;
.
SCCT
j
GooTronhic.'il Area
. rifles + M]]j
,,..
+ :,;
H
-
5.01
- .i
't.63
6.'t8
7.v'-»
- ^^
/» J/.X
r- **|.
^ • -^ •
PKF
9.16
12.6?,
8.0<*
10. '»2
Overall
S.W«lo« + K
Overall
6.90
3.90
„ ,,,,
x - -.
17.95
13.06
6.0't
10.98
9.««0
*».'»?
a in
Ss= 72.15 d . f . = VpS
ASH
Pathological ;
^TvTf'
'•' 4 '• '•/'"
M
1.96
F
M2
2.58
5.0^
PKF
6.87
't.67
Overall
— ^— ->' f- + "'^0 — '
u '.'nip .
~
Overall
3.95
1.29
2.^0
2.71
't.32
7.07
6.77
10.M*
•..'96
6.90
5.62
7.80
3.13
•..93
2
S = 12.3't d.f. = l*?8
Pathological
Ty);C
!
SCOT
(jR>su)
!
;
G e o r r a n H c a l Arc?.
N>; + iNW
; i;.v/r,l.cs + MD
(i;;:TiZ)
;
(AcciKUi;s:O
S.V.'r.lns + K
(blor'HIV-.v)
Overall
ri
'»r\o
O **-~>f
r^ 4'/n
^ . y/ /
U.5b^
'-'. !?3
i"
O.bSi
0.862
PKF
1.138
1.209
1.275
1.992
0.390
0.770
0.359
0.730
1.191*
L'f'tg
0.1.66
0.83**
Overall
•0.765
i
»
0.952
s
S t= O.'iOSS d . f . = 't?8 KAOLItl * MICA
_ . . . .
Patholoncal ,
iype
M
F
PMF
Overall
;
,.„
SCCT
(jiticu)
!
+
G e o p r n r h i c a l Area
,;w
K .-. V , 1(>B + v ^
(Li/'.fYa)
1.17
2.66
<t.50
1.62
3.29
^.69
3.01
3.70
:
(;iC",KL;;j;iX)
S.Walos + K
:
(:ii:niivw)
Overall
2.29
».53
6.85
0.88
1.»*9
1.95
3.72
2.93
i 5.10
2.29
3.31*
1
'*.7<*
S3 = 6.131 d , f . = l*78
TAV-T..K A . ' i
f>nn f i r u r e s for 3>i",r; dun I woin:litf. found in th^ throe nntholoric.''.! t y n c n . The
collioric;; r.rc co':i!iino.1 into four croups forrinn t!1.^ inturrl coMi-in-'itions of
foorrnphicol fire;i.
C o l l i e r i e s comprisiup each pcojrnpliical nroa nre fiven in
brockets.
S2 = residual variation.
d.f. = ar.soeiatnd dt.'grees of freedom.
137.
COAL
Pathological
Type
KFI
WK
:
Co~l. Hon < Grout)
via
A>.Vi:>:
K01.GJIDZ
l:ca:)J
Overall
H
79.08
79.03
71. 0<t
67.58
58.90
62.85
70.23
F
81.57
76.148
67.27
51.23
1*8.65
58.07
6<t.3?
PMF
79.20
75.76
66.96
1*8. i* it
39.96
1*3.82
59.1*1
Overall
80.33
76.68
68.05
51.33
ii7.25
51*. 77
63.65
S
2
= 200.1*
d>f.
^ l»72
ASH
Pathological
Type
Cool Han k Gronr
VTB
AMV.'X
Overall
'..'L'
KFI
M
21.11
20.96
28.96
32.36
!»1.08
37.05
29.76
F
18.1*0
23.50
32.73
W.71*
5L36
1*1.95
35-62
PMF
20.81
21*. 23
33.06
5L55
60. oi*
56.11*
1*0.59
Overall
19.71
23.31
3L96
1-8.59
52.75
1*5.20
36.35
~ 200.5
d . f . = 1*72
if
Pathological
Tyne
'n't
1
hFI
j
Coal Rank Grourt
:
VTB
ALYNX
KOLG1IDK
! KOLG'.IDZ
|
PCS-QJ
!
PCSqj
Overall
K
2.91*
2.95
<*.21
1..65
6.25
5.77
l*.l*0
F
2.72
S.^
5.58
9.28
8.75
7. "3
6.0^
PMF
3.22
3.92
5.92
9.1*1*
11.30
10.36
7.29
Overall
2.91
3.55
5.31
8.91*
9.26
7.80
6.19
S* = 9.7"3 d.f. ^ !*72
KAOLIN + MICA
Pathological
Type
Coal Rank Group
VTB
,
/iKYNX
KOLGUUZ
PCStyJ
Overall
19.16 .
25.77
21.95
18.63
22.72
32.73
31.72
26.81*
23.91*
18.32
22.02
33.1?
38.70
37.10
27.26
16.79
21.27
31.72
33.30
28.75
2l*. 15
WE
HFI
M
15.28
13.88
17.81
F
11*.03
16.68
PMF
17.02
Overall
15.12
£?= 103.2
TARLL A.5
.
d.f. = 1*72
Mean figures for lung dust percentage composition found in the three
pathological types.
The collieries are combined into six groups by the
rank of coal mined.
SE =
residual variation.
d.f. -
associated decrees of freedom.
These firures were derived hy etanrf'ird nnnlysis of variance
techniques.
Coal
Rank
Group
Mineral
Component
HFI
VTB
AKYNX
KOLGUDZ
PCSQJ
% COAL
HFI
VTB
AMYNX
KOLGUDZ
PCSQJ
% NON-COAL
HFI
VTB
AMYNX
KOLGUDZ
PCSQJ
% QUARTZ
HFI
VTB
AMYNX
KOLGUDZ
PCSQJ
% KAOLIN
+ MICA
HFI
WE
M*
F*
11 IF'
M
i
F
_
_-
VTB
PMF
M
F
AKTOX
FHF
M
F
X
-
X
_
_
_
_
X
X
X
::
::
X
X
X
-
X
X
..
_
X
-
X
.
_
_
_
X
*\
..
-
X
::
3:
3:
-
X
=:
X
_
_
X
X
X
X
-
-
X
_
_
X
X
X
X
-
-
X
_
_
X
X
X
X
X
-
-
X
X
X
X
X
-
X
X
_
_
_
_-
X
X
X
X
X
X
-
-
X
X
-
X
X
X
X
X
X
-
| PMF
M
j-
PKF
-
-
-
-
-
-
!
i
_
1
X
X
KOLGUDZ
_
_
_
_
_
_
-
-
..
_
_
-
_
_
_
-
-
-
-
-
-
-
-
-
-
-
~
X
-
X
>:
-
X
X
-
-
X
.
TABLE A.6
Multiple comparisons for differences between mean percentage mineral component for each coal rank area for each
pathological type.
•
Pathological type
NOTE:
For each percentage ccmponent tabie the confidence that all the statements implied in the table are
correct is at least V.%.
"x" denotes that the difference under consideration was significant within
the overall family of comparisons.
Bonferroni t-statistics wer3 used for the calculations within
each percentage comporent table.
All contrasts within the family were compared wj.th equal confidence.
139.
COAL
Pathological
Type
SCOT
(JK.'Stl)
!
Geo^ranhical Area
ME + !«'A'
! N . V m l e n * I - ' J U •. S.V.'ales + K
(iwm)
| (AC!!Kii-...-:x)
(Bf.FHIV/. 1 )
Overall
68.90
PMF
68.72
67.65
53.82
63.18
61.13
58.76
4%'>5
37.88
75.28
74.32
73.62
68.63
64.26
60.38
Overall
62.33
63.09
44.58
74.31
63.65
M
F
E
S = 203.5
d . f . = 4?8
ASH
Pathological
ijij«
SCOT
(JPOSU)
H
31.17
F
PKF
32.33
46.18
Overall
37.63
!
Geographical Area
NE * KV;
i N . ' J p l P s + MTI1
(D;-:TYZ)
(ACGKLiUyJi)
51.09
36.80
4-i.l8
54.56
38.8?
36.90
Overall
T. . V a l p r . - V.
G'.EiiilVW)
I
62.11
24.76
25.67
26.37
35.73
39.62
55. Vl
25.69
36.35
31.37
?
S = 203.6 d.f. = V?8
QUARTZ
Pathological
Type
SCOT
(JPOSU)
M
**.<)<)
F
5.1»2
PMF
8.^5
Overall
6.53
1"
Kii + tin
(iJI-.TY?.)
GeoKrarchical Area
i .'i.'.t'ales + KID
: (ACGKI,r.;'KX)
S.V.'nles + K J
(BLFH1VV.O
Overall
6.07
11.95
3.41
3.89
4.19
10.30
3.88
6.19
4.76
6.13
6.98
10.24
6.32
6.39
4.74
7.08
s
S = 8.993 d . f . = <t?8
KAOLIN + KICA
FatiiiMugjuttl
Type
S'JOT
(J PCS U)
PMF
17.65
20.80
29.09
Overall
23.33
M
F
N. Wales + l-UH
|
«
( Ui-iTYZ )
Overall
19.60
23.97
26.73
24.15
23.87
35.49
25.68
40.61
16.20
18.36
19.16
24.03
35.85
18.12
19.33
25.06
Ss = 100.4
TABLK A.?
S. '.Vales + K
(Bi.i'Hl'VW;
d.f. = 478
Mean figures for lung dust percentage composition in the three
pathological types.
The collieries are combined into four groups
forminf; the natural combinations of preof;raphical area.
The
collieries comprising each geographical area are given in brackets.
S2 = residual variation,
d.f. = associated degrees of freedom.
These fipures were derived by standard analysis of variance techniques.
APPENDIX B
A preliminary statistical investigation into the relationship
between lung dust and dust exposure.
INTRODUCTION
The aim of this work has been to try to establish a relationship
betv;een lung dust content (gms) and dust exposure (gm hrs m~3) for
autopsy study cases.
All 119 men satisfying the "acceptable exposure"
criterion (see page 30 of the report) have been included in this
analvsis.
Whilst some more exploratory analysis is desirable, this
Appendix describes the work done so far and the considerations used in
determining the work reported.
The two main questions which this analysis was directed towards
were:
Question 1:
Given the three pathological types assigned at autopsy
does the rate of retention for cases vary between pathological types.
Question 2:
Does this rate of retention vary between coal rank
areas given possible susceptibility differences between the pathological
types.
The following investigations are based on linear regression
techniques.
AN APPRAISAL OF POSSIBLE MODELS
There is a significant overall correlation of G.^T- between lung dust
weight and dust exposure. The first representation considered related
lung dust weight to dust exposure by the following:
lung dust weight - 80 + aj x exposure + as if pathological type M
+ a3 if pathological type F
+ a* if case originated from coal rank area 1
+ as if case originated from coal rank area 2
•f as if case originated from coal rank area J>
where OQ , a^,..., as are estimated coefficients.
reported.)
(These results are not
This is a standard linear regression equation but with the
constant term varying over pathological types and coal rank area, of
origin.
All groups of cases are hypothesised to have the same average
rate of retention, interpreted as the slope of the relationship with
exposure.
This model does not allow for the hypothesis suggested by
question 1.
Discussions suggested that an improvement to the above
model v;ould be obtained by varying the coefficient of exposure term
between pathological types and coal rank areas.
This would allow
average retention rates to vary for men in the different categories
of interest.
It was also suggested that the constant term would have
little meaning when considered from a practical viewpoint.
Whilst
most of the non-mining population have traces of dust in the lung it
was felt that such levels would be negligible in the case-of the miners
ccr.cidcrcd. ^rr^ v?v01o*0^ <•« CVVM-VRIIVP wn-.ld thorn fore be expected
to be non-significant.
Some analyses were carried out to investigate
whether or not the exclusion of constant terms changed the model
significantly.
To simplify the discussion of the possible models, consideration
is only given here to separation by pathological type for total dust
weight in lung and exposure.
Model 1
.'
This representation is:
lung dust weight = 80 + aj if case was assigned to pathological type M
+33 if case was assigned to pathological type F
+ bo x dust exposure
+ bj x dust exposure if case was assigned to
pathological type M
+ hs x dust exposure if case was assigned to
pathological type F
i.e. comparisons are made against a "standard" of PMF.
ao , a^,... ba are
estimated coefficients.
The values of these estimated coefficients are shown in Table B.1 .
This regression was highly significant (p < .001) with 2.2tf> of the
variance of lung dust weight being accounted for by pathological type
differences as specified in the model.
This model suggests the following.
The constants a1 and £fe are not significantly different from zero although
ao is highly significant.
The constants are all individually
significant
at 10?o, bj and b^ being significant at 5$>. The pairwise differences
between the b's are not significant. This model is illustrated in
Figure B.1.
'
1A2.
Interpretation of the model is not straightforward.
face value,
M
Taken at
cases appear to be able to be exposed to more dust
before, accumulation in the lung takes place than either F or PHF cases
who rapidly build up lung dust initially.
Once accumulation does
begin, it takes place at a higher rate for M cases than for F or PMF,
the rate of build-up for F cases being higher than for PMF cases.
Over most of the range of data, the model predicts the observed
gradation of lung dust levels between the three pathology types, it is
only at the higher and more scattered end that the explanation of the
mortal conflicts with other analyses.
In any case, rrigid extrapolation
of the models at this level of dust exposure is dubious.
This is clearly not
the data.
the "best" regression that; could be fitted to
Given traditional significance levels, the model includes
terms which make non-significant contributions; further analysis would
be directed towards removing these terms from the model and searching
for other variables which may correlate with lung dust weight.
Model 2
Restructuring of the above model to allow only one overall constant
term was considered as an improvement to the above formulation.
The
equation used for this was:
lung dust weight = Co + do x dust exposure
+ dj x dust exposure if case was assigned to
pathological type M
+ cc x dust exposure if case was accigr.cd tc
pathological type F
Again, comparisons are made against a "standard" of PMF.
The values of
the estimated coefficients Co , do , dt and d?are given in Table A.2.
The
regression was highly significant with a similar percentage of variance
being accounted for.
For this model, co , do and d^ are all individually
significant at the 5$ "level.
zero.
63 is not significantly different from
This model is illustrated in Figure
B.2.
Given that all cases initially reach the same lung dust weight,
cases eventually graded PMF have absorbed more of the dust that they were
exposed to than F cases or M canes, although the rate for F cases is not
significantly different from PMF cases.
Model 3
This model was considered because of the suggestion that lung dust
weight would be expected to bo proportional to exposure.
The
formulation was:
lung dust weight = fx x dust exposure if case was assigned to
pathological type M
+ fa x dust exposure if case was assigned to
pathological type F
+ f3 x dust exposure if case was assigned to
pathological type FMF
where fj, fa , f3 are estimated coefficients their values being given in
Table B.3. This model, illustrated as Figure ^.13 of the report, shows
the proportional relationship between lung dust and exposure based on
the assumption that zero exposure implies zero lung dust.
The rates of
retention for different groups may easily be compared.
In terms of the data sets available, it is not strictly meaningful
to test the significance of individual slopes when fitting a model of this
type.
Non-significance implies that the slope of the relationship for
the particular group is not significantly different from zero. This is
inherently meaningless when negative data values are impossible.
A DISCUSSION OF_THE THREE MODELS
There is no unique statistical procedure for selecting the best
equation from any given set.
It is inevitable that some element of
personal judgement will be involved in the choice.
To add more
subjectivity to the choice, not all models necessarily lead to the same
solution when applied to the came problem.
In many cases they will
achieve the same answer, but in others they do not.
The three models
considered above do lead to slightly differing results and it is necessary
to consider the interpretation of the models with regard to the questions
asked of them.
By the nature of the data analysed no case has both lung dust weight
and dust exposure close to zero.
The form of the relationship in this
region thus precludes investigation.
All the models considered assume
that the relationship is linear over this range.
The basic difference
between the models is what postulations ere made about the initial build-up
of lun<r dust, since tliese postulatior.s affect the linear relationship over
the range of the data.
Model 1 shows that for any category of cases lung dust weight is
determined by a "minimum" value adjusted by an exposure dependent value.
Comparison of retention rates between any two groups thus necessitates
consider" !.i on of both oor.stantE and raj eves for the two groups.
This
model also suggests so;r,e rnec-anisi!; of initial build-uf of lung dust which
varies over the pathological types such that after this build-up they
retain duct, at different rates.
This formulation nay therefore he
considered with the possibility of individual susceptibility determining
the eventual pathological grading.
Tv,e, <v^^-,.i .,.r.,ifO •>v~"i^!'?r'- th'iv ?.'. ".-.::"•* 1.~:: level" cf du:;t ll-.c'/r. ;r,:,v
not be any differences between the eventual pathological types.
Following the iritia] V-uild-T^; there are varying averts rates of
retention between the pathology types.
This model begs the question that the pathological types separate
themselves only after a given amount of dust has been retained in the
lung.
The third model assumes a directly proportional rate of retention,
based on the Assumption that zero dust exposure implies zero dust in the
lung.
The relationship between lung dust v.-eight and dust exposure is
assumed to be linear.
The fitted relationships may be regarded as the
average of all such individual relationships.
Given the questions of interest it was decided that the preliminary
investigations presented in the report would be based on Model 3« the
directly proportional approach.
Clearly this decision is one which will
provoke discussion in thr future.
It is hoped that subsequent work will
include analyses of a more sophisticated type since each model above
relates to differing research questions.
THE-SPECIFIC ANALYSIS
Two variations of Model 3 have been formulated to answer the
questions posed in the introduction.
Question 1
The variation used to try to answer this first hypothesis was:
lung dust
V,
. ., = L
component weight
._
t
i
,_
N
Ui< x dur.t conronent exnosure)
'
where BJ - constant if case; was assigned to pathological type i
= 0 otherwise.
145.
Pathological type 1 is macules; type 2 is fibrotic nodules and
type 3 is PMF.
These constants are estimated by the analysis and are
given in Table 4.2 of the report.
With the exception of total ash, there is an increase in the
coefficients over the three levels of pathology.
In many cases the
increase between adjacent pathological types is not significant at
conventional levels.
The coefficient of exposure associated with any
one group is the expected amount (in grams) by which lung dust content
is increased when dust exposure is increased by 1 gm hr m~3 .
The most
ica.ouiia.uxc c/^pj.uiiuLa.wn c/j. i»i»c j.iuu^.i*>^c ci >,»xic cu".—lydc.' ir. ...u. ,r.c~c
—~,
with the exception of ash, an increasing trend in the retention rates of
minerals as the level of pathology increases..
This trend is not
significant at any of the usual levels of significance.
The
fluctuation of results for ash could easily have arisen by chance.
A secondary aim of fitting this model was to investigate the
hypothesis that dust in the lungs of PMF cases has been "enriched" with
respect to the non-coal minerals compared to dust in lungs which have •
soft macules or fibrotic lesions.
Of particular interest is the
selective retention of quartz in PMF lungs.
These hypotheses were
formulated from preliminary published analyses (DAVIS ^t al_., 1977).
This model does not clearly answer this question, except t^ the
extent that given a 1 gm hr m~3 increase in exposure of each of the dust
components, more of the quartz would be expected to be retained; again
no traditional significance is attached to this result, but it is noted
that it is in keeping with the hypothesis.
Graphs for results relating to dust and quartz have been presented
as Figures 4.13 and 4.14 of the report.
Question 2
The second variation was formulated as:
3
4 f
1
lung dust
= £ £ jb
I
component weight ~._.
..
|
ij
x
dust
component
exposure]
1-1
3='
|^
J
where b. . = constant if case was from coal rank are j and placed in
^
pathology group i at autopsy
= 0 otherwise
Table 4.2 of the report shows the estimated values of the coefficients
together with their standard errors.
As for the first model, these
standard errors are mainly for use in testing differences between the
(b. .). Comparisons are not given here.
^- J
It i« from this analysis that the fitted relationships shown in
Figures 15, 16, 1? and 18 of the report have been evaluated.
It should be noted that this analysis has been carried out on only
119 men distributed over 12 pathology group/coal rank area combinations
with the inevitable result that in some combinations there are few cases.
A discussion of these results has been incorporated into the report.
1V?.
Estimated
Value
Standard
Error
(ao)
(ai)
(as)
10.69
-17.50
- 4.28
2.67
Dust exposure
(bo)
Additional dust exposure for pathological type M (bj)
tt
it
it
ii
p (bs)
ii
ii
0.07
0.04
Coefficient
Constant
Additional constant for pathological type M
ti
TABLE B.1
it
ii
it
n
p
Constant
Dust exposure
Additional dust exposure for pathological type M
n
ii
ii
n
ii
ti p
Estimated
Value
(CD)
(do)
(dj)
(do)
0.04
0.02
0.01
Standard
Error
8.46
2.06
0.04
0.01
- 0.02
0.01
- 0.01
0.01
Efit.imat.pri
Stonrtn-rri.
Estimated coefficients for Model 2.
Coefficient
Dust exposure : pathological type M
11
it
II
U
F
it
It
II
" PMF
TABLE B . 3
4.28
Estimated coefficients for Model 1.
Coefficient
TABLE B.2
0.03'
11.08
Estimated coefficients for Model 3»
Value
Error
(fx)
It TL
.011
(fs)
C£i
.004
.06
.004
(fa)
55
•
MACULES
O
NODULES
A
P. M.F.
50.
45 .
A
WEIGHT OF DUST
IN
MACULES
40
NODULES
35 .
BOTH LUNGS (gm)
P. M.F.
30.
25
20
15
10
5
10(>
200
300
400
500
600
700
DUST EXPOSURE ( gm h m';! )
FIG.B.1. AN ILLUSTRATION OF MODEL 1
800
55
•
MACULES
O
A
NODULES
R M. R
50.
45.
WEIGHT OF DUST
IN
40
P.M.F.
NODULES
O
35
BOTH LUNGS ( g m )
30.
25
MACULES
20
15
10
5
100
200
300
400
500
600
DUST EXPOSURE ( gm h m"3 )
FIG.B.2. AN ILLUSTRATION OF MODEL 2
700
800
150.
APPENDIX C
X-ray readings
In the present study 261 chest radiographs taken within four years
of death were read in two sessions by four doctors from the National
Coal Board's Periodic X-ray Service.
There was considerable variation
between the classifications awarded by the four readers to some of the
cases.
Statistical summaries of these variations are given in Table C.1.
and a brief description of the statistics is as follows:(1) The consistency coefficient is an indication of the amount of
agreement between readers in the classification of films.
(2} The bias coefficient is a measure of the degree to which one
reader of a pair of readers consistently classifies films higher
or lower on the 12-point scale than the other.
(3) The bias score coefficient measures the degree of bias in terms
of "steps per 100 men" on the 12-point scale.
CO
The correlation coefficient indicates the extent of non-systematic
variation.
Because of this inter-reader variability, a complete analysis of
radiographic classifications and levels of lung pathology should have been
undertaken in four exercises with the gradings of each reader taken
separately.
This will be done at a later stage but for the preliminary
analysis in the present report an averaging process was used to produce a
single radiographic classification for each case.
The procedure used to
produce the mean score or average reading varied with the type of radiographic classification. For the profusion grades of small rounded and
small irregular opacities the ILO 12-point scale was converted to a 12point notional scale of -1 to +10 for each reader. , The notional scale
readings were summed and a mean score was assigned to the radiograph
according to Table C.2. For the reading of opacity types recorded as two
characters (e.g. pr, qr for small rounded opacities and st, tu for small
irregular opacities) the readings have been grouped according to the
first letter of the pair (e.g. pq and pp classified as p) and the modal
(most frequently occurring) value used as the "average".
In cases where
an even split in grading had occurred between the four readers, the case
number was used as a "random tie-breaker", an odd number resulting in
the lower classification being assigned and an even number resulting in
preference being given to the higher classification.
readers agreed, no "average" was given.
Where no two
Prevalence of
category 0/1+
(<;/•)
\,o /
Consistency
coefficient
(12 pt.)
(50
Consistency
coefficient
Ct pt.)
(<)
Correlation
coefficient
Bias
coefficient
Bias score
coefficient
Small rounded
opacities
1st group of X-ra.ys
^9.^(39.8-61.9)
if?. ?'>6. 0-50.6) 63.3(59.0-67.6) 0.73(0.67-0.7'7) 22.0(18.3-27.7)
-5.3(^.1-7.2)
2nd group of X-rays
(k readers)
58.6(^.^-70.7)
37.5(31.1+-1+0.5)
11.8(8.8-16.8)
(*f readers)
5^.9(^1.7-60.2) 0.69(0.66-0.70
^5.8(35.9-56.7)
Small irregular
opacities
33.5(2^.5-^3.3) 57.5(5^.8-59.^) 70.8(67.8-73.8) O.^7(0.37-0.5;0 16.2(12.7-18.7)
(k readers)
.
2nd group of X-rays 25.M13.2-39.6) 6*t.9<.58.8-68.5) 73.5(66.5-77.2) 0.60(0.56-0.6o) 23.1(20.7-25.7)
1st group of X-rays
(k readers)
APPENDIX C, TABLE C.1
Autopsy study filn-reading - inter-reader statistics.
3.8(3.^-^.3)
5.5(^.9-6.1)
152.
Mean
Score
Total
Score
-^ to
5
9
-1
1
0
2
1
3
2
'4
3
2
10
11 to 13
3
1U
'*
15 to 1?
18
5
22
25
26
27 to 29
i
7
6
8
1
8
-
7
9
8
10
9
9
38
39 to to
5
7
3<*
35 to 39
6
6
30
31 to 33
^
'5
19 to ?'l
23 to
0
1
6
7 to
X-roy No. is odd
0
+1
2
3 to
X-ray No, is evra
-1
-3
-2
-1 to
Mean Score
10
APPENDIX C, TABLE C.2
Procedure for calculating the mean score
for small opacities.
(A20115) IOM (R) ReportCov art
3/15/06
12:32 PM
Page 2
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historical research report

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