Beijing pollution may trigger heart attack...( CHICAGO -- Olympic athletes aren't ...),Health

CHICAGO -- Olympic athletes aren't the only ones who need to be concerned about the heavily polluted air in Beijing. The dirty air may trigger serious cardiovascular problems for some spectators.

Two researchers in pulmonary medicine and critical care at Northwestern University's Feinberg School of Medicine warn that for people in certain risk groups, breathing high levels of pollution can cause heart attacks and strokes within 24 hours of exposure and increase the possibility of having blood clots in their legs on the plane home.

The people who are vulnerable include those who already have known cardiovascular disease or risk factors for cardiovascular disease such as high blood pressure, high cholesterol, diabetes, obesity, lung disease, a current smoking habit or a family member diagnosed with heart disease before age 55.

"If the air quality is bad, you are more likely to have serious heart disease related events," said Gokhan Mutlu, MD, assistant professor of medicine at the Northwestern's Feinberg School and a physician at Northwestern Memorial Hospital. "Being exposed to higher levels of pollution may unmask heart disease even if you've never had any symptoms."

Mutlu published research in 2007 that showed how pollution triggers heart attacks and strokes. He discovered that microscopic air pollution -- particles less than one-tenth of the diameter of a human hair -- makes the blood thicker and sticky. He found when lungs are inflamed by pollution, they secrete a substance, interleukin-6, which causes an increased tendency for blood to clot.

Previous studies have shown that thousands of people in the U.S. die from strokes and heart attacks within 24 hours of a spike in microscopic pollution from the exhaust of diesel trucks, buses and coal-burning factories.

A more recent study has shown that people who live in polluted
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