Aircraft noise linked to higher rates of heart disease, stroke near Heathrow

Risks of hospital admissions and deaths from stroke and heart disease are higher in areas with high levels of aircraft noise, a study has found.

Researchers at Imperial College London and King's College London compared data on day- and night-time aircraft noise with hospital admissions and mortality rates among a population of 3.6 million people living near Heathrow airport.

The risks were around 10 to 20 per cent higher in areas with highest levels of aircraft noise compared with the areas with least noise.

The findings are published in the British Medical Journal.

Previous research has found links between living in a noisy environment and risk of high blood pressure, but few studies have looked at stroke, heart disease and circulatory disease.

The new findings raise the possibility that aircraft noise may be a contributing factor to these conditions, but the researchers say more work is needed to establish the exact relationship between noise and ill health.

Dr Anna Hansell, from the School of Public Health at Imperial, the lead author of the study says, ''These findings suggest a possible link between high levels of aircraft noise and risk of heart disease and stroke. The exact role that noise exposure may play in ill health is not well established. However, it is plausible that it might be contributing, for example by raising blood pressure or by disturbing people's sleep. The relative importance of daytime and night-time noise also needs to be investigated further.''

Professor Paul Elliott, the senior author of the study and director of the UK Small Area Health Statistics Unit and MRC-PHE Centre for Environment and Health where the study was conducted, add, ''From this type of study, we can't say for certain that aircraft noise is responsible for the increased heart disease and stroke risk in these communities as there are other possible explanations.

''It's worth bearing in mind that there are many other factors that are known to have important influences on an individual's risk of heart disease and stroke , such as diet, smoking, lack of exercise and medical conditions such as raised blood pressure and diabetes. However, our study does raise important questions about the potential role of noise on cardiovascular health, which needs further study''

The study covered 12 London boroughs and nine districts outside of London where aircraft noise exceeds 50 decibels – about the volume of a normal conversation in a quiet room.

The whole study area was divided into 12,110 small areas, each with a population of around 300. For each small area, the researchers looked at noise levels from 2001, provided by the Civil Aviation Authority, and hospital admissions and deaths from 2001-2005.

The researchers also considered other factors in those areas that have been linked to heart disease rates, like social deprivation, ethnic composition, road traffic noise, air pollution and lung cancer rates – a proxy for the prevalence of smoking.

After adjusting for these factors, South Asian ethnicity – which is associated with higher risks of heart disease – was found to account for part of the association between heart disease admissions and noise levels, as many areas with the most noise also have large South Asian populations.