People living in residential areas with high levels of noise from road traffic appear to suffer more heart attacks than people living in quieter neighborhoods, according to a new study by researchers at the Swedish medical university Karolinska Institute in Stockholm.

Goran Pershagen, who led the study, said 1571 people from the Stockholm area who had suffered heart attacks between 1992 and 1994 were compared with a control group from the same area. The addresses of all the individuals were indentified and the level of noise estimated.

Exposure to air pollution and other heart attack risk factors were also gathered using questionnaires and interviews, the researchers said. Once people with impaired hearing or exposure to other sources of noise had been eliminated from the study, the researchers found that there was a 40 percent higher risk of a heart attack in people exposed to traffic noise exceeding 50 decibels — a relatively quiet level of noise; heavy traffic is usually measured at between 80 and 90 decibels.

"More research will be needed to establish a definite correlation between road traffic noise and [heart attacks], but our results are supported by other studies showing the cardiovascular effects of noise," Pershagen said.

The possible link between noise and heart attacks should be taking into account when planning new roads and residential areas, he added. The study was published in the journal Epidemiology.

Inside Science News Service is supported by the American Institute of Physics.