Is the prevalence of peanut allergy increasing? A 5-year follow-up study in children in Montreal.
BACKGROUND
Studies suggest that peanut allergy prevalence might be increasing, but these results have not yet been substantiated.


OBJECTIVE
We conducted a follow-up study to determine whether peanut allergy prevalence in Montreal is increasing.


METHODS
Questionnaires regarding peanut ingestion were administered to parents of children in randomly selected kindergarten through grade 3 classrooms between December 2000 and September 2002 and between October 2005 and December 2007. Respondents were stratified as (1) peanut tolerant, (2) never/rarely ingest peanut, (3) convincing history of peanut allergy, or (4) uncertain history of peanut allergy. Children in group 3 with positive skin prick test responses were considered to have peanut allergy. Children in groups 2 and 4 with positive skin prick test responses had peanut-specific IgE levels measured, and if the value was less than 15 kU/L, an oral peanut challenge was performed. Multiple imputation was used to generate prevalence estimates that incorporated respondents providing incomplete data and nonrespondents.


RESULTS
Of 8,039 children surveyed in 2005-2007, 64.2% of parents responded. Among those providing complete data, the prevalence was 1.63% (95% CI, 1.30% to 2.02%) in 2005-2007 versus 1.50% (95% CI, 1.16% to 1.92%) in 2000-2002. After adjustment for missing data, the prevalence was 1.62% (95% credible interval, 1.31% to 1.98%) versus 1.34% (95% credible interval, 1.08% to 1.64%), respectively. The differences between the prevalences in 2005-2007 and 2000-2002 were 0.13% (95% credible interval, -0.38% to 0.63%) among those providing complete data and 0.28% (95% credible interval, -0.15% to 0.70%) after adjustment for missing data.


CONCLUSIONS
This is the first North American study to document temporal trends in peanut allergy prevalence by corroborating history with confirmatory tests. The results suggest a stable prevalence, but wide CIs preclude definitive conclusions.
Ben-Shoshan
Moshe
M
Department of Pediatrics, Division of Clinical Immunology/Allergy and Rheumatology, McGill University Health Centre, Montreal, Quebec, Canada.
Kagan
Rhoda S
RS
Alizadehfar
Reza
R
Joseph
Lawrence
L
Turnbull
Elizabeth
E
St Pierre
Yvan
Y
Clarke
Ann E
AE
D010367:Arachis / Q000276:immunology; D002170:Canada / Q000453:epidemiology; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D008297:Male; D021183:Peanut Hypersensitivity / Q000453:epidemiology*; D015995:Prevalence
D007073:Immunoglobulin E