UK researchers say long-term exposure to aircraft noise increases the risk of heart disease and stroke. A five year study focusing on the noise produced by planes flying in and out of Heathrow reveals a higher rate of hospitalisation for people living near the airport than for those who live in quieter environments.
LONDON, ENGLAND, UNITED KINGDOM (OCTOBER 24, 2013) (REUTERS) - People living near busy airports endure loud aircraft noise every day, but now British researchers have found that the noise may also increase their risk of heart disease and stroke.
Researchers at London's Imperial College say their study, published in the British Medical Journal, has found a link between exposure to high levels of aircraft noise near busy airports and a higher risk of both conditions.
Dr. Anna Hansell, lead author of the study, says that the risks are around 10 to 20 percent higher in areas with the highest levels of aircraft noise compared with those with least noise.
"In the highest noise levels, so these were the areas generally speaking closer to Heathrow airport, we found around a 10 to 20 percent increased risk of both hospital admissions and deaths from heart disease and stroke, and that was associated both with the highest levels of the daytime noise and the highest levels of the night-time noise," she said.
Hansell says there are a number of ways that aircraft noise can affect a person's health - from lack of sleep and anxiety to repeated exposure to sudden noises causing a 'startle reaction', which can contribute to higher blood pressure and stress levels.
"There's a startle reaction when you hear a loud noise, so your heart rate goes up, your blood pressure goes up, and it may be that if you're exposed to loud noise over a long period of time that your blood pressure just stays up rather than going back down again to normal, and there are another couple of ways that might affect your blood pressure, which is people, some people, get really annoyed by loud noise, and that may increase your stress levels and increase your blood pressure," she said.
The study of 3.6 million people living near Heathrow, one of the busiest airports in the world, compared hospital admissions and death rates due to stroke and heart disease from 2001 to 2005 in 12 areas of London and nine districts to the west ofLondon.
Levels of aircraft noise were obtained from the Civil Aviation Authority (CAA), and any other factors that could have affected the results, such as age, sex, ethnicity and smoking were taken into account.
The results showed an increased risks of stroke, coronary heart disease, and cardiovascular disease, especially among the two percent, about 70,000 people, who were exposed to the highest levels of aircraft noise.
The study has fuelled the already fierce debate over the possible expansion of Heathrow airport.
John Stewart, chair of campaign group Heathrow Association for the Control of Aircraft Noise (HACAN) welcomes the study's findings, saying that people living under the flight path in London frequently complain that the noise affects their stress levels and health.
"So many people living under the flight path tell us it affects their health. Sometimes it's people who are woken up every morning when the first plane comes in at five thirty, they can't sleep, they're stressed out. Other times, it's people during a day saying that this constant noise is really getting on their nerves, they're taking tablets, they feel stressed out and, I'm sure, as the study shows, it eventually affects their health," he said.
Stewart says he hopes the study will halt any potential plans to build a third runway at Heathrow.
"I think this study should be the final nail in the coffin of any thoughts to expand Heathrow. Already, people are suffering very badly. Even more people, hundreds of thousands of more people, would be stressed out if expansion went ahead and their health too would be affected," he said.
Residents living under the flight path have mixed feelings about the aircraft noise.
Clive Thorp, who has lived under Heathrow's flight path for most of his life, says he barely notices the noise.
"I'm 70 now and I've lived here and near here, all my life, and I'm still going strong," he said from his home in Hatton Cross.
"They put nice windows, it's no noises, you can hear nothing here, it's no problem, you know," said another resident.
"It's widely known sound is energy, and energy does have effect on people's health," said another..
A separate U.S. study, also published in the British Medical Journal, had similar results to the UK study and found that there was a higher rate of admission to hospital with heart problems for people living near 89 airports.
Researchers at the Harvard School of Public Health and Boston University School of Public Health looked at data for more than six million Americans aged 65 or over living near 89 U.S. airports in 2009.
The research found that, on average, areas with 10 decibel (dB) higher aircraft noise had a 3.5 percent higher cardiovascular hospital admission rate.
The results showed that people exposed to the highest noise levels had the strongest link with hospitalisations for heart disease, and the link also remained after adjustment for other factors such as socio-economic status and air pollution.
Hansell cautions that the Imperial study does not prove a definite link. She says further research is required and that the higher risk of ill health related to aircraft noise remains less significant than the risks from other factors such as smoking or diet.
"We think from the results that we've seen so far, it's likely to be a relatively small impact, so stopping smoking is going to be, you know, much more important for your health, or if you've got high blood pressure or high cholesterol, making sure that's treated properly, but we think we really do need some more work to look at this because environmental noise is something that potentially most of the population are exposed to and, you know, if we can reduce the noise levels that's certainly good for the people who get annoyed by noise, and may also have some really positive benefits on health as well," she said.
While diet, exercise and smoking can all raise people's risks of heart disease, researchers maintain that the link between aircraft noise and ill health should not be ignored, and efforts should be made to try to reduce noise levels for those living near busy airports.