Academics found an association between long-term exposure to the roar of road traffic and death rate, as well as the risk of stroke. People exposed to daytime traffic noise louder than 60 decibels (dB) were four per cent more likely to die than those living in areas where noise levels were less than 55 dB.
The extra deaths mostly involved heart or artery disease – which could in turn be linked to raised blood pressure, sleep problems and stress brought on by noise, the scientists claimed. A total of 8.6 million people living in London between 2003 and 2010 provided data for the study, reported in the European Heart Journal.
Lead scientist Dr Jaana Halonen, from the London School of Hygiene and Tropical Medicine, said: “Road traffic noise has previously been associated with sleep problems and increased blood pressure, but our study is the first in the UK to show a link with deaths and strokes.
“This is the largest study of its kind to date, looking at everyone living inside the M25 over a seven-year period. Our findings contribute to the body of evidence suggesting reductions in traffic noise could be beneficial to our health.”
The World Health Organisation defines 55dB as a noise level that can cause health problems in a community. In London, more than 1.6 million people are exposed to daytime road traffic noise louder than this threshold. Although 55dB is roughly equivalent to listening to a loud conversation, research suggests that continuous noise at this level may be harmful.
The study also found that adults living in areas with the noisiest daytime traffic were five per cent more likely to be admitted to hospital for stroke than those from quieter neighbourhoods. For the elderly, this increase in risk rose to nine per cent.
Between 2003 and 2010, a total of 442,560 adults from the study population died from all causes, of whom 291,139 were elderly.
The scientists looked at levels of road traffic noise between 7am and 11pm, and at night between 11pm and 7am, across different postcodes and correlated the findings with death and hospital admission rates. Factors – including individuals’ age and sex as well as ethnicity, smoking levels, air pollution and socio-economic deprivation – were taken into account.
Commenting on the findings, Dr Tim Chico, a consultant cardiologist at the University of Sheffield, said: “This study cannot and does not prove that noise causes cardiovascular disease, although its findings are consistent with other studies showing that noise increases blood pressure, and this could contribute to developing cardiovascular disease.
“There may be other factors that link high noise areas with cardiovascular disease, and it is difficult to take all of these into account. Nevertheless, given what we know about traffic emissions increasing heart disease, we should remember that travelling by foot or bike is definitely healthier – both for you and for the people around you.”
And Professor Jeremy Pearson, the British Heart Foundation’s associate medical director, added that the study shows there is a “detectable, but very small, excess risk” of cardiovascular death amongst people exposed to high levels of traffic noise.
He added: “The results suggest reducing air pollution from traffic is more important for heart health than reducing noise.”