Traffic-related air pollution and incident asthma in a high-risk birth cohort.

TitleTraffic-related air pollution and incident asthma in a high-risk birth cohort.
Publication TypeJournal Article
Year of Publication2011
AuthorsCarlsten, C, DyBuncio, A, Becker, A, Chan-Yeung, M, Brauer, M
JournalOccup Environ Med
Volume68
Issue4
Pagination291-5
Date Published2011 Apr
ISSN1470-7926
KeywordsAir Pollutants, Air Pollution, Asthma, Bronchial Hyperreactivity, Environmental Exposure, Environmental Monitoring, Epidemiologic Methods, Epidemiological Monitoring, Female, Geographic Information Systems, Humans, Infant, Newborn, Male, Particulate Matter, Vehicle Emissions
Abstract

OBJECTIVES: The risk of incident asthma and bronchial hyper-reactivity associated with early life exposure to traffic-related air pollution has not been fully elucidated. We aimed to evaluate the hypothesis that the risk of new onset asthma is positively associated with early exposure to traffic-related air pollution in a well-characterised high-risk birth cohort.METHODS: Infants at high-risk for asthma were recruited for an intervention study. Birth year exposures to NO, NO(2), black carbon and PM(2.5) were estimated by land use regression. At 7 years of age, asthma was assessed by a paediatric allergist and bronchial hyper-reactivity was measured by methacholine challenge. Associations between exposures and outcomes were analysed by stepwise multiple logistic regression, adjusted for potential confounding variables.RESULTS: Exposure estimates were available for 184 children; 23 were diagnosed with asthma and 68 with bronchial hyper-reactivity. The IQR (4.1 μg/m(3)) of birth year PM(2.5) was associated with a significantly increased risk of asthma (OR 3.1, 95% CI 1.3 to 7.4) and with a trend to increased risk of bronchial hyper-reactivity. Similar findings were noted in association with NO and NO(2), while black carbon did not appear to confer increased risk.CONCLUSION: Modest elevations in exposure to some traffic-related air pollutants during the year of birth are associated with new onset asthma assessed at age 7. That significant associations were revealed in spite of a limited sample size emphasises the strengths of a high-risk birth cohort model, along with individual air pollution exposure estimates and well-characterised data on covariates and outcomes.

DOI10.1136/oem.2010.055152
Alternate JournalOccup Environ Med
PubMed ID20952556
Grant List / / Canadian Institutes of Health Research / Canada