People who put up with the constant roar of aircraft overhead may be at higher risk for heart disease, two new studies suggest.
In one study, British researchers compared rates of stroke and heart disease among 3.6 million people who lived near London's sprawling Heathrow airport, one of the busiest transit hubs in the world.
The results showed that these people were at heightened risk for death and hospitalisation from heart issues. The risk was highest among the 2% of the study population exposed to the highest daytime and night-time levels of aircraft noise, the team said.
In the second study, researchers analysed data from more than 6 million people aged 65 and older who lived near 89 US airports during 2009. On average, people who lived in zip codes with 10 decibel higher levels of aircraft noise had a 3.5% higher rate of hospitalisation for heart disease.
As in the British study, the association between hospitalisation for cardiovascular disease and aircraft noise was strongest among people exposed to the highest levels of aircraft noise, say researchers led by Dr Francesa Dominici of the Harvard School of Public Health.
Heart experts weren't surprised by the findings.
Environmental noise effects
"Despite the thought that perhaps aircraft noise might [only] be a cause of sleep disturbances, of being disruptive or a mere irritation, these studies are showing the real health threat of airport noise," said Dr Suzanne Steinbaum, a preventive cardiologist at Lenox Hill Hospital in New York City.
"Certainly this information should become an important issue when deciding where to live, or in city planning for the future," she said.
Dr Sripal Bangalore, a cardiologist at NYU Langone Medical Centre in New York City, said the new research "adds to growing literature on environmental-related risk factors for cardiovascular disease".
"One is left to wonder whether aircraft technicians, maintenance personnel and ground crews who are not only at risk of job-related hearing loss, are also at high risk of cardiovascular disease," said Bangalore, who is also assistant professor in department of medicine at NYU.
The authors of the British study said that cities like London are under enormous pressure to meet the demands of the airline industry. "However, policy decisions need to take account of potential health-related concerns, including possible effects of environmental noise on cardiovascular health," wrote a team led by Paul Elliott of Imperial College London.
Both studies were published online in the journal BMJ.com. While the studies showed an association between chronic exposure to aircraft noise and heart trouble, they were observational in nature and could not prove a cause-and-effect relationship.
The U.S. National Institutes of Health outlines what you can do to reduce heart risks.