Heavy traffic may trigger heart attacks

Science News, Nov 13, 2004

People at risk of heart attacks should steer clear of traffic, a new study suggests. Researchers in Germany have found that exposure to traffic can dramatically increase a person's risk of having a heart attack soon afterward.

The researchers analyzed the medical records of 691 heart attack survivors in Augsburg, in southern Germany, during a recent 30-month period. After surveying the study volunteers about their activities up to 4 days before a heart attack, the researchers found that a person's risk of being stricken nearly tripled in the hour after being in traffic. Lead author Annette Peters of the GSF-National Research Center for Environment and Health in Neuherberg says that she and her colleagues were "surprised by the size" of the increased risk.

Most of the people in the study were riding in their cars within an hour before the onset of a heart attack, but the elevated risk from traffic exposure was nearly the same for those traveling by bus, trolley, bicycle, or motorcycle. The total time spent in traffic was directly related to the size of the increased risk.

Peters says it's impossible to determine whether the elevated risk was due to traffic-related pollution or to other factors, such as stress. Other studies have linked exposure to particulates in air pollution with increased risk for heart disease (SN: 8/2/03, p. 72).

The German study appears in the Oct. 21 New England Journal of Medicine. In an accompanying commentary, Peter H. Stone of Brigham and Women's Hospital in Boston argues that the new data--when considered in the context of known triggers for heart attacks--provide "compelling" evidence that particulates in air pollution may trigger a heart attack. --D.P.