(HealthDay News) – Short-term exposure to all major air pollutants, except for ozone, is significantly associated with an increased risk of heart attack, according to a study published in the Feb. 15 issue of the Journal of the American Medical Association.

Hazrije Mustafic, MD, MPH, of the University Paris Descartes, and colleagues conducted a systematic literature review and performed a meta-analysis of 34 studies. Keywords related to the type of exposure (air pollution, ozone, carbon monoxide, nitrogen dioxide, sulfur dioxide, particulate matter ≤10µm [PM10], and PM ≤2.5µm [PM2.5]) and to the type of outcome (myocardial infarction [MI], heart attack, and acute coronary syndrome) were searched. Short-term exposure was defined as exposure of up to seven days. Analysis was based on each increment of 10µg/m³ in pollutant concentration, with the exception of carbon monoxide, for which an increase of 1mg/m³ was used.

The researchers found that all the main air pollutants, except for ozone, were significantly associated with an increase in MI risk (carbon monoxide: relative risk [RR], 1.048; 95% CI, 1.026–1.07; nitrogen dioxide: RR, 1.011; 95% CI, 1.006–1.016; sulfur dioxide: RR, 1.01; 95% CI, 1.003–1.017; PM10: RR, 1.006; 95% CI, 1.002–1.009; and PM2.5: RR, 1.025; 95% CI, 1.015–1.036). The relative risk for ozone was 1.003 (95% CI, 0.997–1.01; P=0.36). Subgroup analyses provided similar results. Population attributable fractions ranged between 0.6% and 4.5%, varying by pollutant.

“All the main air pollutants, with the exception of ozone, were significantly associated with a near-term increase in MI risk,” the authors write.

Several authors disclosed financial ties to pharmaceutical and medical device companies.

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