Low concentrations of fine particle air pollution and mortality in the Canadian Community Health Survey cohort
Authors:Christidis, TanyaErickson, Anders C.Pappin, Amanda J.Crouse, Daniel L.Pinault, Lauren L.Weichenthal, Scott A.Brook, Jeffrey R.van Donkelaar, AaronHystad, PerryMartin, Randall V.Tjepkema, MichaelBurnett, Richard T.Brauer, Michael
Source:ENVIRONMENTAL HEALTH
Volume:18
Published:2019
Document Type:Article
Abstract:Background Approximately 2.9 million deaths are attributed to ambient fine particle air pollution around the world each year (PM2.5). In general, cohort studies of mortality and outdoor PM2.5 concentrations have limited information on individuals exposed to low levels of PM2.5 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 PM2.5 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 PM2.5. 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 PM2.5 exposure estimates, and mortality incidence to 2016. Cox proportional hazard models were used to estimate the relationship between non-accidental mortality and ambient PM2.5 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 PM2.5 concentrations were low (i.e. 5.9 mu g/m(3), s.d. 2.0) and each 10 mu g/m(3) 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 mu g/m(3) using a shape constrained health impact function. Mortality risks associated with exposure to PM2.5 were increased for males, those under age 65, and non-immigrants. Hazard ratios for PM2.5 and mortality were attenuated when gaseous pollutants were included in models. Conclusions Outdoor PM2.5 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 PM2.5 concentrations.
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Reprint Address:Christidis, T (corresponding author), STAT Canada, Hlth Anal Div, 100 Tunneys Pasture Driveway, Ottawa, ON K1A 0T6, Canada.
Addresses:[Christidis, Tanya; Pappin, Amanda J.; Pinault, Lauren L.; Tjepkema, Michael] STAT Canada, Hlth Anal Div, 100 Tunneys Pasture Driveway, Ottawa, ON K1A 0T6, Canada. [Erickson, Anders C.; Brauer, Michael] Univ British Columbia, Sch Populat & Publ Hlth, 2206 East Mall, Vancouver, BC V6T 1Z3, Canada. [Crouse, Daniel L.] Univ New Brunswick, Dept Sociol, POB 4400, Fredericton, NB E3B 5A3, Canada. [Weichenthal, Scott A.] McGill Univ, Dept Epidemiol Biostat & Occupat Hlth, 1110 Pine Ave West, Montreal, PQ H3A 1A3, Canada. [Weichenthal, Scott A.] Hlth Canada, Air Hlth Sci Div, 269 Laurier Ave West, Ottawa, ON K1A 0K0, Canada. [Brook, Jeffrey R.] Univ Toronto, Dalla Lana Sch Publ Hlth, 155 Coll St, Toronto, ON M5T 1P8, Canada. [van Donkelaar, Aaron; Martin, Randall V.] Dalhousie Univ, Dept Phys & Atmospher Sci, 6310 Coburg Rd,POB 15000, Halifax, NS B3H 4R2, Canada. [Hystad, Perry] Oregon State Univ, Coll Publ Hlth & Human Sci, 2520 SW Campus Way, Corvallis, OR 97331 USA. [Martin, Randall V.] Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. [Burnett, Richard T.] Hlth Canada, Populat Studies Div, 50 Columbine Driveway, Ottawa, ON K1A 0K9, Canada. [van Donkelaar, Aaron; Martin, Randall V.] Washington Univ, Dept Energy Environm & Chem Engn, St Louis, MO 63130 USA. [Brook, Jeffrey R.] Univ Toronto, Dept Chem Engn & Appl Chem, 223 Coll St, Toronto, ON M5T 1R4, Canada. [Pappin, Amanda J.] Hlth Canada, Safe Environm Directorate, 269 Laurier Ave West, Ottawa, ON K1A 0K9, Canada.
E-mail Addresses:tanya.christidis@canada.ca