Exposure to traffic and mortality risk in the 1991-2011 Canadian Census Health and Environment Cohort (CanCHEC)

TitleExposure to traffic and mortality risk in the 1991-2011 Canadian Census Health and Environment Cohort (CanCHEC)
Publication TypeJournal Article
Year of Publication2019
AuthorsCakmak S., Hebbern C., Vanos J., Crouse D.L, Tjepkema M.
JournalEnvironment International
Volume124
Pagination16-24
Date Published2019/03
Type of ArticleArticle
ISBN Number0160-4120
Accession NumberWOS:000457122700003
Keywordsair pollution; air-pollution; associations; climate; diabetes-mellitus; Environmental health; Environmental Sciences & Ecology; fine particulate matter; follow-up; health; long-term exposure; lung-cancer; mortality; nitrogen-dioxide; ozone exposure; respiratory; symptoms; traffic
Abstract

There is evidence that local traffic density and living near major roads can adversely affect health outcomes. We aimed to assess the relationship between local road length, proximity to primary highways, and cause-specific mortality in the 1991 Canadian Census Health and Environment Cohort (CanCHEC). In this long-term study of 2.6 million people, based on completion of the long-form census in 1991 and followed until 2011, we used annual residential addresses to determine the total length of local roads within 200m of postal code representative points and the postal code's distance to primary highways. The association between exposure to traffic and cause-specific non-accidental mortality was estimated using Cox proportional hazards models, adjusting for individual covariates and contextual factors, including census division-level proportion in high school, the percentage of recent immigrants, and neighborhood income. We performed sensitivity analyses, including adjustment for exposure to PM2.5, NO2, or O-3, restricting to subjects in core urban areas, and spatial variation by climatic zone. The hazard ratio (HR) for all non-accidental mortality associated with an interquartile increase in length of local roads was 1.05 (95% CI 1.04, 1.05), while for an interquartile range increase in proximity to primary highways, the HR was 1.03 (95% CI 1.02, 1.04). HRs by traffic quartile increased with increasing lengths of local roads, as well as with closer proximity to primary highways, for all mortality causes. The associations were stronger within subjects' resident in urban core areas, attenuated by adjustment for PM2.5, and HRs showed limited spatial variation by climatic zone. In the CanCHEC cohort, exposure to higher road density and proximity to major traffic roads was associated with increased mortality risk from cerebrovascular and cardiovascular disease, ischemic heart disease, COPD, respiratory disease, and lung cancer, with unclear results for diabetes.

DOI10.1016/j.envint.2018.12.045
Student Publication: 
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