Low concentrations of fine particle air pollution and mortality in the Canadian Community Health Survey cohort

Tanya Christidis; Anders C Erickson; Amanda J Pappin; Daniel L Crouse; Lauren L Pinault; Scott A Weichenthal; Jeffrey R Brook; Aaron van Donkelaar; Perry Hystad; Randall V Martin; Michael Tjepkema; Richard T Burnett; Michael Brauer

doi:10.1186/s12940-019-0518-y

Low concentrations of fine particle air pollution and mortality in the Canadian Community Health Survey cohort

Environ Health. 2019 Oct 10;18(1):84. doi: 10.1186/s12940-019-0518-y.

Authors

Tanya Christidis¹, Anders C Erickson², Amanda J Pappin^{3

4}, Daniel L Crouse⁵, Lauren L Pinault³, Scott A Weichenthal^{6

7}, Jeffrey R Brook^{8

9}, Aaron van Donkelaar^{10

11}, Perry Hystad¹², Randall V Martin^{10

13

11}, Michael Tjepkema³, Richard T Burnett¹⁴, Michael Brauer²

Affiliations

¹ Health Analysis Division, Statistics Canada, 100 Tunney's Pasture Driveway, Ottawa, Ontario, K1A 0T6, Canada. tanya.christidis@canada.ca.
² School of Population and Public Health, The University of British Columbia, 2206 East Mall, Vancouver, British Columbia, V6T 1Z3, Canada.
³ Health Analysis Division, Statistics Canada, 100 Tunney's Pasture Driveway, Ottawa, Ontario, K1A 0T6, Canada.
⁴ Safe Environments Directorate, Health Canada, 269 Laurier Avenue West, Ottawa, Ontario, K1A 0K9, Canada.
⁵ Department of Sociology, University of New Brunswick, PO Box 4400, Fredericton, New Brunswick, E3B 5A3, Canada.
⁶ Department of Epidemiology, Biostatistics & Occupational Health, McGill University, 1110 Pine Ave West, Montreal, Quebec, H3A 1A3, Canada.
⁷ Air Health Science Division, Health Canada, 269 Laurier Avenue West, Ottawa, Ontario, K1A 0K0, Canada.
⁸ Dalla Lana School of Public Health, University of Toronto, 155 College Street, Toronto, Ontario, M5T 1P8, Canada.
⁹ Department of Chemical Engineering and Applied Chemistry, University of Toronto, 223 College St., Toronto, ON, M5T 1R4, Canada.
¹⁰ Department of Physics and Atmospheric Science, Dalhousie University, 6310 Coburg Road, PO Box 15000, Halifax, NS, B3H 4R2, Canada.
¹¹ Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri, 63130, USA.
¹² College of Public Health and Human Sciences, Oregon State University, 2520 SW Campus Way, Corvallis, Oregon, 97331, USA.
¹³ Harvard-Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA, 02138, USA.
¹⁴ Population Studies Division, Health Canada, 50 Columbine Driveway, Ottawa, Ontario, K1A 0K9, Canada.

Abstract

Background: Approximately 2.9 million deaths are attributed to ambient fine particle air pollution around the world each year (PM_2.5). In general, cohort studies of mortality and outdoor PM_2.5 concentrations have limited information on individuals exposed to low levels of PM_2.5 as well as covariates such as smoking behaviours, alcohol consumption, and diet which may confound relationships with mortality. This study provides an updated and extended analysis of the Canadian Community Health Survey-Mortality cohort: a population-based cohort with detailed PM_2.5 exposure data and information on a number of important individual-level behavioural risk factors. We also used this rich dataset to provide insight into the shape of the concentration-response curve for mortality at low levels of PM_2.5.

Methods: Respondents to the Canadian Community Health Survey from 2000 to 2012 were linked by postal code history from 1981 to 2016 to high resolution PM_2.5 exposure estimates, and mortality incidence to 2016. Cox proportional hazard models were used to estimate the relationship between non-accidental mortality and ambient PM_2.5 concentrations (measured as a three-year average with a one-year lag) adjusted for socio-economic, behavioural, and time-varying contextual covariates.

Results: In total, 50,700 deaths from non-accidental causes occurred in the cohort over the follow-up period. Annual average ambient PM_2.5 concentrations were low (i.e. 5.9 μg/m³, s.d. 2.0) and each 10 μg/m³ increase in exposure was associated with an increase in non-accidental mortality (HR = 1.11; 95% CI 1.04-1.18). Adjustment for behavioural covariates did not materially change this relationship. We estimated a supra-linear concentration-response curve extending to concentrations below 2 μg/m³ using a shape constrained health impact function. Mortality risks associated with exposure to PM_2.5 were increased for males, those under age 65, and non-immigrants. Hazard ratios for PM_2.5 and mortality were attenuated when gaseous pollutants were included in models.

Conclusions: Outdoor PM_2.5 concentrations were associated with non-accidental mortality and adjusting for individual-level behavioural covariates did not materially change this relationship. The concentration-response curve was supra-linear with increased mortality risks extending to low outdoor PM_2.5 concentrations.

Keywords: Air pollution; Canada; Cohort study; Fine particle air pollution; Fine particulate matter; Mortality; PM2.5.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Aged
Aged, 80 and over
Air Pollutants / adverse effects*
Air Pollution / statistics & numerical data
Canada / epidemiology
Cardiovascular Diseases / mortality*
Environmental Exposure / adverse effects*
Female
Health Surveys
Humans
Incidence
Male
Middle Aged
Particulate Matter / adverse effects*
Prospective Studies
Public Health
Respiratory Tract Diseases / mortality*
Risk Assessment

Substances

Air Pollutants
Particulate Matter

Grants and funding

R-82811201/U.S. Environmental Protection Agency/International