Blood points to pollution’s heart risks

Hospitals admit more patients for heart problems on days when air pollution is bad. A new study reveals that as airborne concentrations of fine dust particles climb, so do three blood factors that increase an individual’s heart attack risk.

Joel Schwartz of the Harvard School of Public Health in Boston correlated blood data for more than 5,000 men and women with measurements of air pollution on the day their blood had been drawn. The randomly selected adults were among participants in a large federal survey on diet and health.

To assess pollution exposures, Schwartz collected readings from all air-monitoring stations in and around each volunteer’s home county, giving more weight to the nearer stations. He then correlated data for the pollutants with measurements of three agents in the volunteers’ blood that can signal heart problems: platelets and fibrinogen, both of which promote blood clotting, and white blood cells, which can signal that plaque inside arteries may soon rupture and block vessels.

In a June supplement to Environmental Health Perspectives, Schwartz reports that of all the pollutants measured, only fine particulates–those smaller than 10 micrometers in diameter–were associated with higher than normal concentrations of these blood agents. The size of the rise increased with dose. Accounting for people’s diet, smoking, exposure to indoor pollution, and income didn’t diminish the “robust” link, says Schwartz.

These data “imply that important cardiovascular factors can be modified by airborne particles at commonly occurring concentrations,” Schwartz concludes.

Janet Raloff

Janet Raloff is the editor of Science News for Students, a daily online magazine for middle school students. She started at Science News in 1977 as the environment and policy writer.

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