Pollution & Stroke Risk

Pollution & Stroke Risk

Short-term exposure to low levels of particulate air pollution may increase the risk of stroke or mini-stroke, according to findings that suggest current exposure standards could be insufficient to protect the public.

Particulate matter is one type of air pollution, defined as tiny particles of solid or liquid, from either man-made or natural sources, which can cause numerous health problems when inhaled. The study examined particulate air pollution in a southeast Texas community where there is a large petroleum and petrochemical industry presence.

"The vast majority of the public is exposed to ambient air pollution at the levels observed in this community or greater every day, suggesting a potentially large public health impact," says lead author Lynda Lisabeth, an assistant professor of epidemiology and affiliate of the UM Stroke Program.

She and her research team identified ischemic strokes and transient ischemic attacks (TIA), sometimes called mini-strokes but that often lead to a stroke later. Ischemic attacks are caused by a blockage of blood flow to the brain by a blood clot. Stroke is the third leading cause of death in the U.S.

Study results showed associations between same-day and previous-day fine particulate matter exposures and ischemic stroke/TIA risk. Similar associations were also seen with ozone, another type of pollution. Despite the fossil-fuel industry in the area, fine particulate matter exposures were low relative to other regions of the country, probably because of the proximity to the coast and prevailing wind patterns.

Lisabeth stresses that the association between particular matter and stroke risk requires further study in other areas with varying climates and alternative study designs.

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