Air Pollution Linked to Blood Clo...( Study suggests dirty air may be even ...),Health

Study suggests dirty air may be even more dangerous than previously thought

MONDAY, May 12 (HealthDay News) -- Long-term exposure to the tiny, dirty particles in polluted air seems to increase the risk of deep vein thrombosis, which are blood clots in the thighs or legs, an Italian study finds.

"It is well-established that air pollution causes myocardial infarction [heart attack] and stroke," said Dr. Andrea Baccarelli, who led the study while at the Harvard School of Public Health. "This is the first time that anyone has connected air pollution with deep vein thrombosis."

Previous studies have suggested such a connection, said Baccarelli, who is now an assistant professor of environmental health at the University of Milan. "Several studies in animal models and in humans have shown that particulate matter, inhaled into the lungs, causes inflammation in the lungs," he said. "The inflammation can expand the cell body, so that the incidence of coagulation is increased."

Coagulation is the formation of clots that can block blood vessels.

Baccarelli and his colleagues assessed the effect of air polluted with particulate matter smaller than 10 micrometers in diameter -- about one-40th the width of a human hair. Such particles come from the exhaust of vehicles, especially those with diesel engines, and burning of fossil fuels, the researchers said.

The scientists compared the exposure to such pollution on 870 residents of the Lombardy region of Italy who had been diagnosed with deep vein thrombosis, and 1,210 residents who did not have deep vein thrombosis. The researchers used the average concentration of particulate matter measured by monitors at 53 sites.

Compensating for other environmental and health factors, the researchers found that the risk of deep vein thrombosis increased by 70 percent for every increase in particulate matter of 10 micrograms per square meter. Tests showed that
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