We’re used to thinking about air pollution as a trigger for asthma, but for heart attack and stroke? A new study in the Journal of the American Medical Association reveals that short-term exposure (for up to seven days) to most major air pollutants (such as carbon monoxide, nitrogen dioxide, sulfur dioxide and particulate matter) appears to increase the immediate risk of suffering a heart attack. The researchers pooled the findings of 34 studies, and analyzed the results—which, for the first time, reveal the link between short-term exposure and immediate heart attack risk. While the risk posed by air pollution is not as powerful as the other known classic risk factors for heart disease—like high cholesterol and high blood pressure, diabetes, obesity, smoking and lack of physical exercise—it’s concerning given the number of Americans who live in polluted urban centers. The researchers speculate air pollution may cause harm through any number of mechanisms, including stimulating inflammation, increasing the heart rate, thickening the blood (making it more likely to clot), and accelerating the hardening of arteries, known as atherosclerosis. Another study this week, published in the Archives of Internal Medicine, revealed that the risk of stroke was 34 percent higher in Boston when pollution levels rose from “good” to “moderate”.
These studies add further confirmation to what’s been suspected for decades, that there is a direct a link between high pollution levels and cardiovascular disease. And, the bad news is, the effects are seen rather immediately and at levels considered safe across many US cities. While the increase in risk may be small for any given individual, the overall toll that air pollution takes on all of us is huge, given that heart attack is the #1 killer and stroke the #3 killer in the US.
What are we to do? Clearly, we need to work for cleaner air regulations and stricter pollution standards—but that will take time. For those who already have heart disease, or are at high risk, and live in smog centers, it may be wise to start paying attention to daily air pollution alerts. Or, consider getting out of Dodge.
Mustafic H et al. Main Air Pollutants and Myocardial Infarction. JAMA. 2012;307(7):713-721. (Accessed on 02-15-2012 at http://jama.ama-assn.org/content/307/7/713.abstract.)
Wellenius G. Ambient Air Pollution and the Risk of Acute Ischemic Stroke. Arch Intern Med. 2012;172(3):229-234. (Accessed on 02-15-2012 at http://archinte.ama-assn.org/cgi/content/abstract/172/3/229.)