Jan. 25, 2011 -- The noises generated by road traffic may increase the risk of stroke, especially in older people, new research indicates.
In a new study, which its authors say is the first to investigate links between road traffic noise and stroke risk, researchers found that for every 10 decibel increase in noise, the risk of having a stroke increased 14% overall in a participant pool of 51,485 people.
Danish scientists say they found no statistically significant increased risk of stroke caused by road noise in people under 65.
The risk, however, increased by 27% for every 10 decibels of higher road traffic noise in people aged 65 and older.
What’s more, the researchers say in a news release that they found indications of a threshold limit of about 60 decibels, above which the risk of stroke seemed to increase even more.
"Our study shows that exposure to road traffic noise seems to increase the risk of stroke," says study author Mette Sorensen, senior researcher at the Institute of Cancer Epidemiology at the Danish Cancer Society in Copenhagen. "Previous studies have linked traffic noise with raised blood pressure and heart attacks, and our study adds to the accumulating evidence that traffic noise may cause a range of cardiovascular diseases."
She says that such findings highlight "the need for action to reduce people's exposure to noise" and that more research is needed before firm conclusions can be made about the apparent links between noise and cardiovascular events. This study shows an association, but cannot prove cause and effect.
The study involved 57,053 people aged 50 to 64 in high traffic areas of Copenhagen and Aarhus, Denmark’s second largest city, between 1993 and 1997.
The researchers say medical and residential histories were available for 51,485 of the participants, and that their average follow-up time was 10 years. During that period, 1,881 had a stroke.
Other Possible Stroke Causes Were Factored Out Before Conclusion Reached
Sorensen and colleagues say they made allowances in the study for the effects of air pollution and exposure to other sources of noise, such as that from railroads and airplanes. They also took into consideration lifestyle factors such as smoking, alcohol and caffeine use, and diet.