Pollution levels linked to stroke-related narrowing of arteries

http://www.eurekalert.org/pub_releases/2015-03/nlmc-pll031315.php

Public Release: 16-Mar-2015
NYU Langone Medical Center / New York University School of Medicine

Air pollution has been linked to a dangerous narrowing of neck arteries that occurs prior to strokes, according to researchers at NYU Langone Medical Center.

The scientists analyzed medical test records for more than 300,000 people living in New York, New Jersey or Connecticut. They found that people living in zip codes with the highest average levels of fine-particulate-matter pollution were significantly more likely to show signs of narrowing (stenosis) in their internal carotid arteries, compared to those living in zip codes with the lowest pollution levels.

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Medical researchers have noticed since the 1950s that episodes of high air pollution can bring temporary jumps in local heart attack and stroke cases. More recent studies have linked heart attack and stroke risks to long-term pollution exposures as well, including PM 2.5 exposures.

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The researchers' analysis showed that subjects in the top fourth of tri-state zip codes, ranked by average PM 2.5 levels, were about 24 percent more likely than those in the bottom quarter to have shown signs of stenosis--defined as a narrowing by at least half--in either internal carotid artery.

"Our study was a population study, so it can't establish cause and effect, but it certainly suggests the hypothesis that lowering pollution levels would reduce the incidence of carotid artery stenosis and stroke," says Dr. Newman.

Scientists aren't yet sure how air pollution contributes to vascular disease. Studies have indicated that it may do so in part by causing adverse chemical changes to cholesterol in the blood, by promoting inflammation, and by making blood platelets more likely to form clots.

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