January 27, 2011

Traffic Noise Ups Risk of Stroke

(Ivanhoe Newswire) -- A new study suggests that exposure to traffic noise could increase your chances of having a stroke.

In a first-of-its-kind study, Dr. Mette Sorensen, senior researcher at the Institute of Cancer Epidemiology, Danish Cancer Society in Denmark, and her colleagues investigated the link between noise on the road and the risk of stroke.

The study was based on a Danish cohort study, which recruited 50- to 64-year-olds, living in the Copenhagen and Aarhus areas between 1993 and 1997. Medical and residential histories were available for more than 51,000 participants, and their average follow-up time was 10 years. During that time, nearly 2,000 participants suffered a stroke.

Researchers found that 35 percent of the participants were exposed to noise levels greater than 60 decibels. The research showed that for every 10 decibels more noise, the chances of having a stroke went up by 14-percent. Researchers noticed that there wasn't a statistically significant increase in risk of stroke for people younger than 65. Meanwhile, for participants older than 64, the risk of stroke increased by 27-percent for every 10dB of higher road traffic noise.

Researchers also took note of the potential effects of air pollution, exposure to railway and air traffic noise, and other health and lifestyle factors. Data on the participants and where they lived were linked to a noise calculation program that takes traffic composition and speed, road type, and the position of people's homes above the roads into account.

Dr. Sorensen was quoted as saying, "If we assume that our findings represent the true risk, and the association between traffic noise and stroke is causal, then an estimated 8 percent of all stroke cases, and 19 percent of cases in those aged over 65, could be attributed to road traffic noise."

Researchers also noted that the population in the study lived mainly in urban areas and is not representative of the whole population in terms of exposure to road traffic noise. They also said that the study doesn't prove that road traffic noise is the cause of increased risk of stroke, only that there is an association, and more research is needed before any firm conclusions can be made.

SOURCE: European Heart Journal, January 26, 2011