Abstract
OBJECTIVES: The prevalence of allergic conditions has been increasing worldwide, with the highest rates seen in Western countries like Canada. The development of allergies is known to be related to both genetic and environmental factors, but the causal pathways remain unclear. Studies on immigrants provide a unique opportunity to disentangle these two factors and provide a better understanding of the disease aetiology. The aim of this study was to investigate the relationship between immigration status and prevalence of non-food allergies in a population-based study of Canadians.
METHODS: Data of 116,232 respondents from the Canadian Community Health Survey (Cycle 3.1, 2005) were used in a multivariable logistic regression to assess the association between immigration status (non-immigrant, long-time immigrant [>10 years] and recent immigrant [≤10 years]) and self-reported doctor-diagnosed non-food allergies, adjusting for potential confounders.
RESULTS: The highest prevalence of non-food allergies was found among non-immigrants (29.6%), followed by long-time immigrants (23.9%) and then recent immigrants (14.3%). The odds of non-food allergies were reduced by 60% (OR = 0.40, 95% CI: 0.35, 0.45) among recent immigrants and 25% (OR = 0.75, 95% CI: 0.70, 0.80) among long-time immigrants, compared with non-immigrants, after adjusting for sex, age, socio-economic status and rurality.
CONCLUSION: This study finds a distinctly lower prevalence of non-food allergies among immigrants compared with non-immigrants, with the difference diminishing with longer duration of residence in Canada. The findings highlight the potential of environmental determinants of allergy development that warrant further investigation, and demonstrate the need for multicultural strategies to manage the public health burden of allergic conditions.
Key words: Allergy and immunology, respiratory hypersensitivity, emigrants and immigrants, socio-economic factors
Résumé
OBJECTIFS: La prévalence des allergies a connu un accroissement global, en particulier dans les pays industrialisés tels que le Canada. Bien qu’il soit établi que les allergies soient liées à des facteurs génétiques et environnementaux, les liens de causalité entre ces facteurs et le développement des allergies restent controversés. Les études portant sur les immigrants présentent une opportunité de discerner ces deux types de facteur et de mieux comprendre l’étiologie de ces maladies. L’objectif de cette étude, fondée sur la population canadienne, était d’explorer la relation entre le statut d’immigration et la prévalence des allergies non-alimentaires.
MÉTHODES: À l’aide des données de l’Enquête sur la santé dans les collectivités canadiennes (ESCC, Cycle 3.1, 2005), nous avons effectué une analyse de régression logistique multivariée auprès de 116 232 participants pour déterminer les effets indépendants du statut d’immigration (non-immigrant, immigrant de long terme [>10 ans] et immigrant récent [≤10 ans]) sur les mesures auto-déclarées de diagnostic d’allergie non-alimentaire par un professionnel de la santé, tout en corrigeant les données de l’effet de variables confusionnelles possibles.
RÉSULTATS: La plus haute prévalence d’allergies non-alimentaires était auprès des non-immigrants (29,6%), suivie des immigrants de long terme (23,9%) et enfin des immigrants récents (14,3%). Les cotes corrigées de l’âge, sexe, statut socio-économique et ruralité ont démontré une diminution du risque de 60 % chez les immigrants récents (CC = 0,40, IC 95%: 0,35, 0,45) et de 25% chez les immigrants de long terme (CC = 0,75, IC 95%: 0,70, 0,80) comparativement aux non-immigrants.
DISCUSSION: Cette étude démontre clairement et de manière significative une plus faible prévalence d’allergies non-alimentaires chez les immigrants comparativement aux non-immigrants, avec une différence qui diminue parallèlement à la durée de résidence au Canada. Dans l’ensemble, ces résultats mettent l’emphase sur la contribution des facteurs environnementaux dans le développement des maladies allergiques et indiquent la nécessité de développer des stratégies multiculturelles pour une meilleure gestion du fardeau de ces maladies sur la santé publique.
Mots clés: allergie et immunologie, hypersensibilité respiratoire, émigrants et immigrants, facteurs socio-économiques
Footnotes
Conflict of Interest: None to declare
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