Exposure to noise from road traffic can increase the risk of stroke, particularly in those aged 65 years and older, according to a study published in the European Heart Journal.
The study, which is the first to investigate the links between road traffic noise and the risk of stroke, found that for every 10 decibels more noise the risk of having a stroke increased by 14% among the 51,485 study participants. When the Danish researchers looked at the data more closely, they found that for people aged younger than 65 years there was no statistically significant increased risk of stroke; however, the risk increased by 27% for every 10 decibels of higher road traffic noise in those aged 65 years and older. Furthermore, in the older people they found indications of a threshold limit at approximately 60 decibels, above which the risk for stroke seemed to increase even more.
“Our study shows that exposure to road traffic noise seems to increase the risk of stroke. 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. These studies highlight the need for action to reduce people’s exposure to noise,” Mette Sorensen, MD, senior researcher at the Institute of Cancer Epidemiology, Danish Cancer Society in Copenhagen, Denmark, who led the research, stated in a press release. “This is the first study ever to investigate the association between exposure to road traffic noise and risk of stroke, and, therefore, more research is needed before any firm conclusions can be made.”
The study was based on the Danish “Diet, Cancer and Health” cohort study, which recruited a total of 57,053 people aged between 50 years and 64 years, in the Copenhagen and Aarhus areas between 1993 and 1997. Medical and residential histories were available for 51,485 of the participants and their average follow-up time was ten years. A total of 1,881 suffered a stroke in this time.
Sorensen and her colleagues made allowances in their calculations for the effect of air pollution, exposure to railway and aircraft noise, as well as a range of other confounding life-style factors such as smoking, diet, alcohol and caffeine consumption. Data on the study participants and where they lived were linked to a noise calculation program that has been used to map noise levels in a variety of locations in Scandinavia for several years.
“If we assume that our findings represent the true risk, and the association between traffic noise and stroke is causal, then an estimated 8% of all stroke cases, and 19% of cases in those aged [older than] 65 [years], could be attributed to road traffic noise,” Sorenson stated.