Exposure to residential road traffic was associated with a higher risk for stroke in people aged over 64.5 years, suggests the epidemiological study, published in the European Heart Journal.
Researchers followed 51,485 participants and found the risk of stroke increased by 27% for every 10dB of higher road traffic noise in those aged 65 years and over. No statistically significant evidence was recorded in younger people.
Dr Mette Sørensen, senior researcher at the Institute of Cancer Epidemiology in Denmark, who led the study, commented: 'The mechanisms involved are probably the same mechanisms believed to be involved in noise-induced hypertension and heart attacks, namely that noise acts as a stressor and disturbs sleep, which results in increased blood pressure and heart rate, as well as increased level of stress hormones.'
The study made allowances in its calculations for the effect of air pollution, exposure to railway and aircraft noise, as well as a range of other confounding lifestyle factors such as smoking, diet, alcohol and caffeine consumption.
If the association between traffic noise and stroke is shown to be causal, then an estimated 8% of all stroke cases, and 19% of cases in those aged over 65, could be attributed to road traffic noise, the researchers suggest.