Ambient PM _2.5 , O ₃ , and NO ₂ Exposures and Associations with Mortality over 16 Years of Follow-Up in the Canadian Census Health and Environment Cohort (CanCHEC)

Abstract

BackgroundFew studies examining the associations between long-term exposure to ambient air pollution and mortality have considered multiple pollutants when assessing changes in exposure due to residential mobility during follow-up.ObjectiveWe investigated associations between cause-specific mortality and ambient concentrations of fine particulate matter (≤ 2.5 μm; PM2.5), ozone (O3), and nitrogen dioxide (NO2) in a national cohort of about 2.5 million Canadians.MethodsWe assigned estimates of annual concentrations of these pollutants to the residential postal codes of subjects for each year during 16 years of follow-up. Historical tax data allowed us to track subjects’ residential postal code annually. We estimated hazard ratios (HRs) for each pollutant separately and adjusted for the other pollutants. We also estimated the product of the three HRs as a measure of the cumulative association with mortality for several causes of death for an increment of the mean minus the 5th percentile of each pollutant: 5.0 μg/m3 for PM2.5, 9.5 ppb for O3, and 8.1 ppb for NO2.ResultsPM2.5, O3, and NO2 were associated with nonaccidental and cause-specific mortality in single-pollutant models. Exposure to PM2.5 alone was not sufficient to fully characterize the toxicity of the atmospheric mix or to fully explain the risk of mortality associated with exposure to ambient pollution. Assuming additive associations, the estimated HR for nonaccidental mortality corresponding to a change in exposure from the mean to the 5th percentile for all three pollutants together was 1.075 (95% CI: 1.067, 1.084). Accounting for residential mobility had only a limited impact on the association between mortality and PM2.5 and O3, but increased associations with NO2.ConclusionsIn this large, national-level cohort, we found positive associations between several common causes of death and exposure to PM2.5, O3, and NO2.CitationCrouse DL, Peters PA, Hystad P, Brook JR, van Donkelaar A, Martin RV, Villeneuve PJ, Jerrett M, Goldberg MS, Pope CA III, Brauer M, Brook RD, Robichaud A, Menard R, Burnett RT. 2015. Ambient PM2.5, O3, and NO2 exposures and associations with mortality over 16 years of follow-up in the Canadian Census Health and Environment Cohort (CanCHEC). Environ Health Perspect 123:1180–1186; http://dx.doi.org/10.1289/ehp.1409276

Cancer incidence attributable to air pollution in Alberta in 2012

“…Also consistent with our RR estimates, a large Canadian-based cohort study estimated a hazard ratio of 1.03 for trachea, bronchus and lung cancers due to PM 2.5 exposure. 17 Using our RR estimates, we estimated that 1.87% (36 cases) to 5.69% (111 cases) of incident lung cancer in Alberta in 2012 were attributable to PM 2.5 exposure. Norman and colleagues 18 completed a similar study in South Africa using the same methods as in the current study and estimated that 5.1% of mortality from cancers of the trachea, bronchus and lung in adults could be attributed to outdoor air pollution (PM 2.5 and PM 10 ), which is more consistent with our sensitivity analysis results.…”

“…We will improve on the present analyses by considering more pollutants such as nitrogen dioxide and using measures of air pollution with accurate spatial and temporal properties, such as those from the Canadian Census Health and Environment Cohort presented in the recent work of Crouse and colleagues. 17 We assumed that the impact of PM 2.5 on lung cancer is uniform across tobacco consumption groups. Given the clear association between tobacco use and lung cancer, if this assumption is not true, our population attributable risk estimates may be an over-or underestimation for certain tobacco consumption groups.…”

Long-Term Ozone Exposure and Mortality in a Large Prospective Study

“…Positive associations were observed with cardiometabolic but not respiratory mortality in multipollutant models adjusted for PM 2.5 and NO 2 in the Canadian CanCHEC study (10). There were no data on potential individual-level behavioral confounding factors, including cigarette smoking, in either study.…”

Estimation of Mortality and Hospital Admissions Attributed to Criteria Air Pollutants in Tehran Metropolis, Iran (2013-2016)

“…Epidemiological studies have shown positive associations between air pollutants such as particulate matter of aerodynamic diameter less than 10 µm (PM 10 ), nitrogen dioxide (NO 2 ), sulphur dioxide (SO 2 ), ozone (O 3 ) and carbon monoxide (CO) and adverse health outcomes (Goldberg et al, 2013;Crouse et al, 2015;Fischer et al, 2015;Liu et al, 2015;Wong et al, 2015;Yorifuji et al, 2016). Many studies have been conducted to assess the health impacts of air pollution in various cities of the world (Boldo et al, 2006;Fattore et al, 2011;Orru et al, 2012;Allen et al, 2013), including Iranian cities (Naddafi et al, 2012a;Gholampour et al, 2014;Ghozikali et al, 2016;Mohammadi et al, 2016).…”