Abstract
Objectives: Exposure to traffic-related air pollutants plays a role in several health outcomes. A large body of evidence tends to link asthma in children with traffic exposure. Increasing asthma prevalence and incidence in children in Canadian cities has been of concern for public health authorities. The following study focuses on estimating the risk of asthma prevalence attributable to residing in proximity to major roads on the Island of Montreal, Canada.
Methods: Risk functions pertaining to asthma in children and residential proximity to major roads were selected from the literature and applied to Montreal. Asthma prevalence was taken from population-based studies. Population data were retrieved from Canadian census. Exposure was estimated using the proximity to major road and highway category of the Desktop Mapping Technologies Inc. database (DMTI Spatial Inc.).
Results: Based on different studies, the percentage of prevalent asthma cases attributable to residing within 50 metres of a major road or highway for children aged 2, 4 and 6 years varied between 2.4% (0–4.3), 5.6% (0.1–8.6) and 5.9% (0.1–9.0). For the 5–7 year age group residing within 75 m of a major road or highway, the percent of cases was 6.4% (2.6–9.3). For children aged 8 to 10 residing within 75 m of a highway only, the percent of cases was 0.7% (0.2–0.9).
Conclusion: These numbers represent the best crude estimates and are an indication of a possible range of cases linked to residential proximity to major roads. As there are uncertainties linked to the application of exposure-response functions, these estimates will be reassessed as new evidence is gathered through further research.
Keywords: Asthma, attributable risks, children, traffic, air pollutants
Résumé
Objectif: L’exposition aux polluants atmosphériques liés au trafic routier contribue à plusieurs résultats sanitaires. De nombreuses preuves tendent à lier l’asthme chez les enfants à l’exposition au trafic routier. La prévalence et l’incidence croissantes de l’asthme chez les enfants dans les villes du Canada préoccupent les autorités de santé publique. Nous avons estimé le risque de prévalence de l’asthme imputable au fait de résider à proximité de grandes artères sur l’île de Montréal, au Canada.
Méthode: Nous avons sélectionné dans la littérature scientifique et appliqué à Montréal les fonctions de risque afférentes à l’asthme chez les enfants et au fait d’habiter à proximité de grandes artères. La prévalence de l’asthme vient d’une étude populationnelle. Les données démographiques sont extraites du Recensement du Canada. Nous avons estimé l’exposition à l’aide d’une catégorie de la base de données de Desktop Mapping Technologies Inc. (DMTI Spatial Inc.): « proximité de grandes routes et artères ».
Résultats: D’après différentes études, le pourcentage de prévalence des cas d’asthme imputable au fait de vivre à moins de 50 mètres d’une grande route ou artère, pour les enfants de 2, 4 et 6 ans, variait entre 2,4 % (0–4,3), 5,6 % (0,1–8,6) et 5,9 % (0,1–9,0). Dans le groupe des 5 à 7 ans vivant à moins de 75 m d’une grande route ou artère, le pourcentage de cas était de 6,4 % (2,6–9,3). Chez les enfants de 8 à 10 ans vivant à moins de 75 m d’une route seulement, le pourcentage de cas était de 0,7 % (0,2–0,9).
Conclusion: Ces chiffres représentent les meilleures estimations brutes et pourraient indiquer un éventail de cas liés au fait de résider à proximité d’une grande route. Il y a cependant des incertitudes liées à l’application des fonctions exposition-réaction; ces estimations seront donc réévaluées à mesure que les chercheurs réuniront de nouvelles preuves.
Mots clés: asthme, risques attribuables, enfant, trafic routier, polluants atmosphériques
Footnotes
Acknowledgements: Elena Boldo was supported by a grant from the Ministry of Science and Innovation and the Carlos III Institute of Health, Spain (Bolsa de Ampliación de Estudios de la Acción Estratégica de Salud. Plan Nacional I+D+i 2008–2011. BOE 58, 08-03-2010).
Conflict of Interest: None to declare.
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