Previous studies had investigated the combined effects of noise and pollution, although the results were inconclusive.
But the latest study of more than 50,000 people has found a "clear relationship" between noise and heart attacks, with researchers from the Danish Cancer Society claiming each ten per cent rise in volume comes with a 12 per cent higher risk of heart attack.
The scientists, who detailed their findings in journal PLoS ONE, said the link could be due to noise causing stress and sleep disturbances.
Dr Mette Sorenson, who led the study, said the reason for the relationship is unknown, but it could be due to increased stress and sleep disturbances linked with high traffic noise.
"In this study residential exposure to road traffic noise was associated with a 12 per cent higher risk of myocardial infarction (MI) per ten decibel exposure to noise, showing a clear dose response relationship," he was quoted as saying by the Daily Mail.
Suggesting one possible explanation, he said that sleep disturbances can contribute to cardiovascular risk, leading to the hypothesis that exposure to noise during the night might be more harmful than daytime exposure.
"The sleep structure generally becomes more fragmented with age and elderly people are thus more susceptible to sleep disturbances," he explained.
Dr Sorenson also said that it was possible that changes in lifestyle caused by disrupted sleep could play a part.
But, he added: "Stress and sleep disturbances can cause changes to lifestyle habits, including increased tobacco smoking and thus potentially a stronger association between traffic noise and MI among smokers.
"However we found indications of a high effect of road traffic noise on MI among never smokers."
The researchers pointed out that those studied mainly lived in urban areas, meaning other factors could be at play.
However, the study shows a positive association between residential exposure to road traffic noise and risk for MI, Dr Sorenson added.
| |
|
| |
