Long-Term Exposure to Air Pollution Is Associated With Survival Following Acute Coronary Syndrome

Study Questions:

What is the association of long-term exposure to air pollution with all-cause mortality?


Records of patients admitted to the hospital with acute coronary syndrome (ACS) using Myocardial Ischaemia National Audit Project (MINAP) data for England and Wales MINAP were collected under the National Institute for Cardiovascular Outcomes Research and linked to modeled annual average air pollution concentrations for 2004-2010. Hazard ratios for mortality starting 28 days after admission were estimated using Cox proportional hazards models.


Among the 154,204 patients included in the cohort, the average follow-up was 3.7 years and there were 39,863 deaths. Mortality rates were higher for individuals exposed to higher levels of particles with a diameter of ≤2.5 µm (PM2.5; PM, particulate matter): the fully adjusted hazard ratio for a 10 µg/m3 increase in PM2.5 was 1.20 (95% confidence interval, 1.04-1.38). No associations were observed for larger particles or oxides of nitrogen. Air pollution explained socioeconomic inequalities in survival to only a small extent.


The authors concluded that mortality from all causes was higher among individuals with greater exposure to PM2.5 in survivors of hospital admission for ACS in England and Wales.


In this study of a large population of patients with advanced ischemic heart disease, long-term exposure to air pollution was associated with all-cause mortality. The association was strongest for PM2.5 concentrations, and there was no evidence of an association for the other pollutants. However, exposure to air pollution explained relatively little of the large socioeconomic gradient in survival. The extent to which this population is at higher risk of death compared with the general population and implications for secondary prevention in this population require additional research.

Clinical Topics: Acute Coronary Syndromes, Prevention, Atherosclerotic Disease (CAD/PAD)

Keywords: Myocardial Ischemia, Acute Coronary Syndrome, Coronary Artery Disease, Follow-Up Studies, Particulate Matter, Nitrogen, Socioeconomic Factors, Oxides, Incidence, Proportional Hazards Models, Secondary Prevention, Cardiovascular Diseases, Confidence Intervals, England

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