Background: Survivors of acute myocardial infarction (AMI) are at increased risk of dying within several hours to days following exposure to elevated levels of ambient air pollution. Little is known, however, about the influence of long-term (months to years) air pollution exposure on survival after AMI.
Objective: We conducted a population-based cohort study to determine the impact of long-term exposure to fine particulate matter ≤ 2.5 μm in diameter (PM2.5) on post-AMI survival.
Methods: We assembled a cohort of 8,873 AMI patients who were admitted to 1 of 86 hospital corporations across Ontario, Canada in 1999–2001. Mortality follow-up for this cohort extended through 2011. Cumulative time-weighted exposures to PM2.5 were derived from satellite observations based on participants’ annual residences during follow-up. We used standard and multilevel spatial random-effects Cox proportional hazards models and adjusted for potential confounders.
Results: Between 1999 and 2011, we identified 4,016 nonaccidental deaths, of which 2,147 were from any cardiovascular disease, 1,650 from ischemic heart disease, and 675 from AMI. For each 10-μg/m3 increase in PM2.5, the adjusted hazard ratio (HR10) of nonaccidental mortality was 1.22 [95% confidence interval (CI): 1.03, 1.45]. The association with PM2.5 was robust to sensitivity analyses and appeared stronger for cardiovascular-related mortality: ischemic heart (HR10 = 1.43; 95% CI: 1.12, 1.83) and AMI (HR10 = 1.64; 95% CI: 1.13, 2.40). We estimated that 12.4% of nonaccidental deaths (or 497 deaths) could have been averted if the lowest measured concentration in an urban area (4 μg/m3) had been achieved at all locations over the course of the study.
Conclusions: Long-term air pollution exposure adversely affects the survival of AMI patients.
1Public Health Ontario, Toronto, Ontario, Canada; 2Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; 3Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada; 4Population Studies Division, Health Canada, Ottawa, Ontario, Canada; 5Department of Family and Community Medicine, University of Toronto, Toronto, Ontario, Canada; 6Department of Health Sciences, Carleton University, Ottawa, Ontario, Canada; 7Department of Medicine, McGill University, Montreal, Quebec, Canada; 8Division of Clinical Epidemiology, McGill University Health Centre, Montreal, Quebec, Canada; 9Division of Cardiovascular Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA; 10Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada; 11Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, Berkeley, California, USA; 12Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA; 13Air Quality Research Division, Environment Canada, Toronto, Ontario, Canada; 14Division of Cardiology, Schulich Heart Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
Recommended Citation:
Hong Chen,1,2,et al. Ambient Fine Particulate Matter and Mortality among Survivors of Myocardial Infarction: Population-Based Cohort Study[J]. Environmental Health Perspectives,2016-01-01,Volume 124(Issue 9):1421