Warning over air pollution link to stroke: research
“However, a lot more research is needed and we’re a long way from confirming that air pollution is a definite risk factor for stroke.
“Everyone can significantly reduce their risk of stroke by eating a healthy balanced diet, excising regularly and having your blood pressure checked.”
They also found that black carbon and nitrogen dioxide, two pollutants associated with vehicle traffic, were closely linked with stroke risk, suggesting that pollution from cars and trucks may be particularly important.
Stroke is a leading cause of long-term disability and the third leading cause of death in the United States. An estimated 795,000 Americans suffer a new or recurrent stroke every year, resulting in more than 135,000 deaths and 829,000 hospital admissions.
The finding that days of moderate air quality substantially elevate stroke risk compared to days of good air quality suggest that the Environmental Protection Agency may need to strengthen the language it uses to describe the health consequences of moderate air quality, researchers say.
“In partnership with NIEHS, EPA funded this research advancing our understanding of air pollution and health effects,” said Dan Costa, ScD, DABT, Interim National Program Director for Air Climate & Energy Research in U.S. Environmental Protection Agency Office of Research and Development Research.
Another study in the same journal linked air pollution to cognitive decline in older women.
A number of studies have demonstrated associations between air pollution and daily death rates for respiratory and heart disease. But findings related to pollution’s effect on stroke have conflicted.
“This study provides new evidence that higher levels of ambient pollutants increase the risk of hospital admissions for stroke, especially on warm days,” he said.
On cool days, researchers noted a link between carbon dioxide levels and ischemic stroke admissions, but believe this may have been a finding by chance.
Many experts suspect that air pollution may affect blood volume and resistance of the blood vessels and heart structures, known collectively as the hemodynamic system. High temperatures may also affect blood viscosity.
“Doctors should know that hemodynamic disturbances that may lead to the risk of cardiovascular events may also lead to an increased risk of other types of circulatory events, such as stroke,” Yang said.
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Co-authors are Shang-Shyue Tsai, Ph.D.; William B. Goggins, Sc.D. and Hui-Fen Chiu, Ph.D.
American Heart Association (2003, October 10)
The authors from Rush University Medical Centre in Chicago, Illinois, and Harvard School of Public Health in Boston, found long-term exposure to air pollution was linked to faster cognitive decline.
Women exposed to ‘typical’ levels of air pollution for between seven and 14 years had the cognitive age of someone two years older, they said.
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By Rebecca Smith, Medical Editor