Air Pollution Linked to Ischemic Strokes
Particulate air pollution (PM10) increases the risk for ischemic strokes — those caused by a blood clot — according to a study by Harvard University researchers.
Hemorrhagic strokes, which occur when a blood vessel ruptures, were not affected by the level of pollution.
Researchers evaluated the link between daily levels of PM10 and hospital admission for strokes among Medicare recipients in nine U.S. cities: Birmingham, Chicago, Cleveland, New Haven, Detroit, Minneapolis, Pittsburgh, Salt Lake City, and Seattle. Compared to days with relatively low particulate air pollution levels, the risk of ischemic stroke — the most common type of stroke — was 1 percent higher on days with relatively higher air pollution. Similar associations were observed for carbon monoxide, nitrogen dioxide and sulfur dioxide.
“It appears that air pollution has only a small effect on acute ischemic events of either the heart or brain, but everybody in those cities is exposed. So, while the relative risk may be small, the absolute risk in terms of excess number of strokes can be quite high, especially when you realize that someone in the United States has a stroke every 45 seconds,” according to the study authors.
Wellenius GA, Schwartz J, Mittleman MA. Air Pollution and Hospital Admissions for Ischemic and Hemorrhagic Stroke Among Medicare Beneficiaries. Stroke 2005; 36:2549-2553.
For a copy of the abstract click here.
