Prevalence of Food Allergies

Prevalence of food allergies: What is KNOWN
What is UNKNOWN
Ann Clarke, MD, MSc
Professor
Division of Rheumatology
University of Calgary
Toronto, June 23, 2015
Overview of Presentation
• Review approaches used to estimate prevalence of food allergy
• Discuss prevalence studies conducted in Canada
Approaches to Assessing Prevalence
• Population sampled
• Geographic location
• City, province, country
• Age
• Milk, egg, wheat, soy – majority outgrow
• Fish, shellfish – develop later in childhood
• Ethnicity
• Dietary habits • Other environmental factors
Approaches to Assessing Prevalence
• How population sampled
•Random population -­ based
•Targeted population – vulnerable populations
•Clinic – based;; if allergy clinic – inflated estimates
• Participation rates will vary
•In population-­based surveys -­ response 35 – 70%
•Non-­allergic less likely to respond, é estimates
•In challenge studies, allergic less likely to respond, ê estimates
• Statistical analysis of missing data
Approaches to Assessing Prevalence
• Definition of food allergy
•Questionnaire • Single question on self-­reported allergy
• Detailed history of reaction symptoms & diagnostic testing
•Diagnostic testing
• SPT – sensitized but not clinically allergic
• Allergen-­specific IgE – threshold depends on pre-­test probability or history
• Food challenge – presents huge obstacles
Canadian Prevalence Studies
Prevalence of peanut allergy in primaryschool children in Montreal, Canada
Rhoda S. Kagan, MD,a Lawrence Joseph, PhD,b,c Claire Dufresne, BScN,d
ARTICLE IN PRESS
Katherine Gray-Donald, PhD,e Elizabeth Turnbull, RN,b Yvan St. Pierre, MA,b and
Ann E. Clarke, MD, MScb,f Montreal, Quebec, Canada
J Allergy Clin Immunol 2003;; 112:1223-­8
Original article
Key words: Peanut allergy; prevalence; skin prick testing; pean
ound: Peanut allergy is receiving increasing attention.
specific IgE measurement; double-blind, placebo-controlled foo
ne study has estimated the prevalence in North Americhallenge
it did not corroborate history with diagnostic testing.
ve: We estimated the prevalence of peanut allergy in
Peanut allergy is receiving increasing public attenti
al by administering questionnaires regarding peanut
It accounts for the majority of severe food-related al
on to children in kindergartena through grade 3 in ranb
c,d
Moshe Ben-Shoshan, MD, Rhoda S. Kagan, MD, Reza Alizadehfar,
MD,a Lawrence
Joseph,
PhD,early,
Elizabeth
Turnbull,
gic reactions,
tends to
present
usually
lasts for l
selectedc schools.
c
d
Quebec,
Toronto, Ontario,
Canadaquantities of peanut
RN, Yvan St Pierre, MA, and Ann E. Clarke, MD, MSc Montreal,
and can
beand
provoked
by trace
ds: Respondents were stratified as follows: (1) peanut
highly sensitized individuals.1-10 Seventy percent to 8
t, (2) never-rarely ingest peanut, (3) convincing history
J Allergy Clin Immunol 2009;; 123:783-­8
credible
interval,
1.31% toto
1.98%)
versushave
1.34%their
(95% first
CI, react
Background:
Studies
suggest history
that peanut
allergy prevalence
ut allergy,
and (4)
uncertain
of peanut
allergy.
of
children
allergic
peanut
1.08% to 1.64%),
The of
differences
betweenat
thethe time
might
increasing, but
these results
have not
yet(SPTs),
been
2, 3,
andbe
4 underwent
peanut
skin prick
tests
between
14 andrespectively.
24 months
age, usually
prevalences in 2005-2007 3,4,9
were 0.13% (95% CI,
substantiated.
he responses
were positive in groups 2 or 4, measureCurrently,
there are no curat
their
first exposure. and 2000-2002
F
Is the prevalence of peanut allergy increasing? A 5-year
follow-up study in children in Montreal
Objective: We conducted a follow-up study to determine
20.38% to 0.63%) among those providing complete data and
Study Aim and Design
• Aim
• To determine if prevalence of peanut allergy increased over 5 years (00-­02 → 05-­07) in Montreal school children
• Hypothesis
• Prevalence will double over 5 years
• Methods • Re-­visit schools randomly selected in 2000-­02
• Random selection of K – Gr 3
• Identical diagnostic criteria
Methods
Grouping by
questionnaire
1 -­ PN tolerant
2 -­ Never
ate
3 -­ Convincing
Hx
4 -­ Uncertain
Hx
Diagnosis
2 or 4
+ SPT AND IgE ≥15
+ SPT AND + DBPCFC
3
+ SPT
IgE ≥0.35
+ DBPCFC
Prevalence: Temporal Change
Full responders
Prevalence Prevalence
2000/02
2005/7
1.50%
1.63%
Difference (95%CI)
0.13%
(-­0.4%, 0.6%)
Full & partial
responders
1.76%
2.06%
0.30%
(-­0.3%, 0.9%)
Full, partial, & non-­
responders
1.34%
1.62%
0.28%
(-­0.2%, 0.7%)
Prevalence of Peanut Allergy
Ben Shoshan 2009
Canada
McGowan 2013
Gupta 2011
Sicherer 2010
USA
Venter 2010
Hourihane 2007
UK
Dutoit 2008
Israel
Osborne 2011
Australia
Shek 2010
Singapore
0
1
2
3
Percentage
4
Is Peanut Allergy Increasing?
Tariq 1996
Grundy 2002
Venter 2010
UK
Sicherer 1997
Sicherer 2002
Sicherer 2010
USA
Kagan 2003
Ben Shoshan 2009
Canada
0
1
Percentage
2
3
6. Matsushima H, Yamada N, Matsue H, Shimada S. The effects of endothelin-1 on
0.5%
degranulation, cytokine, and growth factor production by skin-derived mast cells.
ly 45
Eur J Immunol 2004;34:1910-9.
´
ibited
7. Metz M, Piliponsky AM, Chen CC, Lammel V, Åbrink M, Pejler G, et al. Mast
he al- A population-based
cells can enhance resistance
to snake
and honeybee
venoms.
study
on peanut,
tree
nut,Science
fish,2006;313:
shellfish,
526-30.
nge in and sesame
allergy prevalence in Canada
8. Schneider LA, Schlenner SM, Feyerabend TB, Wunderlin M, Rodewald HR. Molecotherular mechanism
of mast
cell mediated
innateSoller,
defense
endothelinBSc,
and snake
Ben-Shoshan,
MD, Daniel
W. Harrington,
MA, Lianne
BSc, against
Joseph Fragapane,
ficant Moshe
Lawrencevenom
Joseph,sarafotoxin.
PhD, Yvan St
MA, 2007;204:2629-39.
Samuel B. Godefroy, PhD, Susan J. Elliot, PhD, and
J Pierre,
Exp Med
Letters
to
Montreal, Quebec, and Hamilton and Ottawa, Ontario, Canada
MD, MSc
Cs, as Ann E.9. Clarke,
Metz M, Lammel V, Gibbs BF, Maurer M. Inflammatory murine skin responses to
J Allergy Clin Immunol. 2010;;125:1327-­35
ckade Background:
UV-B light are partially dependent on endothelin-1 and mast cells. Am J Pathol
Key words: Food allergy, peanut allergy, tree nut allergy, fish
Recent studies suggest an increased prevalence of
2006;169:815-22.
allergy, shellfish allergy, sesame allergy, perceived food allergy,
food-induced allergy and an increased incidence of food-related
ng. In Hindawi
Publishing
Overall
prevalence
food
probable food allergy, confirmed food allergy
anaphylaxis.
However,Corporation
prevalence
estimates of food allergiesof self-reported
of Allergybetween studies.
mice Journal
vary considerably
Available online May 8, 2011.
Objectives:
To Article
determine
prevalence
Volume
2012,
ID the
858306,
6 pagesof peanut, tree nut,
allergy
in
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Food
allergy
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duced doi:10.1155/2012/858306
doi:10.1016/j.jaci.2011.04.012
fish, shellfish, and sesame allergy in Canada.
to
8%
of
children
less than 3 years of age and is associated with
Soller L et al. J Allergy Clin Immunol. 2012;; 130:986-­8
Methods:
Using comparable methodology to Sicherer et al in the
serum United States in 2002, we performed a cross-Canada, random significant morbidity and mortality. The incidence rate of anaphylaxis is increasing, and recent US reports suggest that it may
To
the
Editor:
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be as high asauto-injectors
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and evidence
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prevalence
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sesame
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Of 10,596 households surveyed in 2008 and 2009, 3666
assive Results:Soller L et al. J Allergy Clin Immunol. 2011;; 128:426-­8
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Research
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responded
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the Editor:
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SCAAALAR:
Surveying CAnadians on the prevalence of food Allergy and Attitudes towards food LAbelling and Risk
• Canadian population in 10 provinces
• Methodology
• Random sampling across provinces
• Household level
• Diagnosis of food allergy
• History
• Unable to do individual assessments
Sampling Frame
10 596 households randomly selected from e-­White Pages
Information letter mailed
Households called
3666 households (35%) participated
9667 individuals
Food Allergy: Definitions
1. Perceived: Self-­reported food allergy
2. Probable: Self report of convincing history and/ or physician diagnosis
3. Confirmed: Clinical history with confirmatory tests provided by treating MD
Prevalence Estimates:
Children
Perceived Probable
Confirmed
Peanut
1.77%
1.68%
1.03%
Tree nut
1.73%
1.59%
0.69%
Fish
0.18%
0.18%
-­
Shellfish
0.55%
0.50%
0.06%
Sesame
0.23%
0.23%
0.03%
Overall Prevalence of Self-­Reported Food Allergy
Including all adults
Excluding some adults
Estimate #2 adjusted for non-­
response
Children Adults
Entire study population
7.14%
8.34%
8.07%
7.14%
6.56%
6.69%
7.12%
6.58%
6.67%
Respondent Characteristics
SCAAALAR
CDN Population
College/University
60.5%
33%
Born in Canada
85.6%
81%
Immigrated < 10 yrs
1.9%
6.3%
Married/ Co-­habit
70.3%
72%
Dwelling owned
82.1%
68%
70K
64K
61 – 84%
68 – 86%
HH income, median
Urban
Knoll et al. BMC Research Notes 2012, 5:572
http://www.biomedcentral.com/1756-0500/5/572
SHORT REPORT
Open Access
The use of incentives in vulnerable populations
for a telephone survey: a randomized
controlled trial
Megan Knoll1*, Lianne Soller1, Moshe Ben-Shoshan2, Daniel Harrington3, Joey Fragapane1, Lawrence Joseph1,4,
Sebastien La Vieille5, Yvan St-Pierre1, Kathi Wilson3, Susan Elliott6 and Ann Clarke1,7
Abstract
Background: Poor response rates in prevalence surveys can lead to nonresponse bias thereby compromising the
validity of prevalence estimates. We conducted a telephone survey of randomly selected households to estimate
the prevalence of food allergy in the 10 Canadian provinces between May 2008 and March 2009 (the SCAAALAR
Original Article
Prevalence and Predictors of Food Allergy in Canada:
A Focus on Vulnerable Populations
Lianne Soller, BSc, MSca, Moshe Ben-Shoshan, MSc, MDb, Daniel W. Harrington, MA, PhDc, Megan Knoll, MSca,
Joseph Fragapane, BEng, MDa, Lawrence Joseph, PhDa,d, Yvan St. Pierre, MAa, Sebastien La Vieille, MDe,
Kathi Wilson, PhDf, Susan J. Elliott, PhDg, and Ann E. Clarke, MSc, MDa,h Montreal, Quebec; Kingston, Ottawa, Toronto, and
Waterloo, Ontario; and Calgary, Alberta, Canada
Clinical
Communications
J Allergy Ciin Immunol Prac 2015;; 3:42-­49
What is already known about this topic? We previously found that 8% of Canadians self-report food allergy. However,
the prevalence of food allergy among those of low education, those with low income, new Canadians, and individuals of
Aboriginal
identity (vulnerable
has not been estimated.
TABLE I. Weighted perceive
Adjusting
for populations)
nonresponse
bias
corrects
of food allergy by age group
overestimates
of tofood
allergy Inprevalence
What
does this article add
our knowledge?
this first Canadian study to estimate the prevalence of food allergy in
a
vulnerable
populations,
thoseMSc,
of low education
and new Canadians
reported fewer allergies, but no differences were
foundunder
Children
Lianne Soller,
BSc,
PhD candidate
,
according to income or Aboriginal status.
18, % (95% CrI
Moshe Ben-Shoshan, MD, MScb,
(n [ 4026)
How does this study impact current management
guidelines? Vulnerablea populations report fewer allergies possibly
c
Daniel
W. Harrington,
MA, PhDhealth
, Megan
Knoll,
, important policy gaps that must be
due
to insufficient
knowledge or inadequate
care access,
whichMSc
suggests
Perceived
a Canadians to seek and receive health
a,d care.
addressed
to
ensure
equal
opportunity
for
all
Joseph Fragapane, BEng, MD , Lawrence Joseph, PhD ,
Peanut
2.4 (1.6, 3.2)
a
e
Yvan St. Pierre, MSc , Sebastien La Vieille, MD ,
nut survey
1.6 (1.0, 2.3)
vulnerable populations), by usingTree
conventional
BACKGROUND: Studies suggest that individuals of low
f
g
the prevalence of Fish
food allergy among
education
income,
new Canadians
<10 years
Kathi and/or
Wilson,
PhD
, Susan(immigrated
J. Elliott,
PhD , methodologies,
and
1.0these
(0.3, 1.8)
populations in Canada has not been estimated.
ago), and individuals of Aboriginal identity
a,hmay have fewer food
Shellfish
1.4 (0.6,
Ann than
E. Clarke,
MScHowever, given the
OBJECTIVES: To estimate the prevalence
of food allergy
among2.1)
allergies
the generalMD,
population.
difficulty in recruiting such populations (hereafter referred to as
J Allergy Ciin Immunol Prac 2015;; 3:291-­3
vulnerable populations in Canada,Sesame
to compare with0.1
the (0.0,
0.3)
Likelihood of being prescribed an epinephrine autoinjector in Canadians with lower educational levels
Soller et al. Ann Allergy Asthma Immunol 2014;;113:326-­9
2015;;166:2199-­207
SPAACE:
Surveying Prevalence of food Allergy in
All Canadian Environments
• Vulnerable populations
• New Canadians
• Low income/ education
• Aboriginal identity
• Methodology
•
•
•
•
Target CTs with >% vulnerable populations
Ensure all regions represented
CTs were converted to postal codes
Random sample of household numbers from these postal codes
Sampling Frame
12 762 households randomly selected from e-­White Pages
Information letter & incentive mailed
Households called
6258 households (49%) participated
15 022 individuals
Respondent Characteristics
SCAAALAR
SPAACE
Below LICO
8.9%
22.8%
CDN Population*
15.7%
Immigrant < 10 yrs
1.9%
11.8%
7.2%
Unknown
15.1%
3.8%
Aboriginal
*Statistics Canada 2006
Prevalence Estimates:
All Participants
SPAACE
Perceived SPAACE
Probable
SCAAALAR
Perceived
Peanut
1.1%
1.0%
1.0%
Tree nut
1.3%
1.2%
1.2%
Fish
0.7%
0.6%
0.5%
Shellfish
1.7%
1.4%
1.6%
Overall
6.4%
_
8.1%
Weighted
Overall
7.5%
_
_
Prevalence Estimates:
Children
Peanut
Fish
Shellfish
Milk
Wheat
SPAACE
SPAACE
Perceived
Perceived
Weighted Unweighted
2.4%
1.9%
(1.6, 3.2)
(1.5, 2.3)
1.0%
0.8%
(0.3, 1.8)
(0.5, 1.1)
1.4%
1.0%
(0.6, 2.1)
(0.7, 1.4)
0.7%
0.5%
(0.3, 1.1)
(0.3, 0.8)
0.3%
0.2%
(0.0, 0.6)
(0.1, 0.3)
SCAAALAR
Perceived
Unweighted
1.8%
(1.2, 2.3)
0.2%
(0, 0.4)
0.6%
(0.2, 0.9)
2.2%
(1.5, 3.0)
0.4%
(0.1, 0.8)
SCAAALAR vs SPAACE
• Weighted cannot be compared with unweighted
• Weighted provides general population estimates
• Cannot calculate weighted for SCAAALAR because no individual level data, particularly on birthplace
• Unweighted cannot be compared with unweighted
• Sampling frame different
• SCAAALAR – random sample
• SPAACE – targeted vulnerable
• Confidence intervals overlap
Prevalence Estimates:
Lower vs Higher Education
Peanut
Lower
Education
0.6% (0.3, 0.9%)
Higher Education
0.8% (0.4, 1.1%)
Tree nut
0.7% (0.4, 1.0%)
1.7% (1.2, 2.3%)
Shellfish
1.5% (1.1, 2.0%)
2.2% (1.6, 2.8%)
Other
2.9% (2.3, 3.5%)
4.1% (3.2, 4.9%)
Overall
6.4% (5.5, 7.3%)
8.9% (7.7, 10%)
Prevalence Estimates:
Immigrant Status
Immigrant
< 10 yrs
Immigrant
≥ 10 yrs
Born in Canada
Peanut
0.4%
0.5%
1.3%
Tree nut
0.2%
0.6%
1.5%
Shellfish
1.3%
1.5%
1.8%
Other
1.3%
2.3%
3.5%
Overall
3.2%
5.5%
8.2%
Prevalence Estimates:
Bias-­Adjusted
Full Participants
Refusal Q Participants
Non-­participants
Never Reached
All
N
Prevalence
15, 022
6.4%
1 393
2.1%
17, 059
1.0 – 4.2%
8 491
1.1 – 6.4%
41, 893
3.0 – 5.4%
What is KNOWN
• Prevalence of self-­reported food allergy in Canada • 7.5%
• Likely an overestimate • Low response rate and the allergic more likely to participate • More realistic estimate likely 4% to 5.4%
• Diagnosis has to rely on hx • Unrealistic to require FC
• Supplement with report of testing
• Increased awareness about food allergy
What is UNKNOWN
• Is the prevalence increasing in Canada?
•
•
•
•
Actual increase Apparent increase because of increased awareness
Cannot rely on self-­report only Appropriate hx is crucial
• What are modifiable risk factors?
• Age and mode of introduction
• How to translate risk into prevention?
Funding