Noise traffic from roads, rails, aircrafts can make you fat from your belly, suggests a new study.
Exposure to a combination of such noise may pose the greatest risk of acquiring a spare tyre, otherwise known as central obesity, and thought to be one of the most harmful types of fat deposition around the body.
The researchers assessed how much road traffic, rail, and aircraft noise 5,075 people living in five suburban and rural areas around Stockholm, Sweden, had been exposed to since 1999.
The analysis indicated no link between road traffic noise and body mass index (BMI). But there was an association between road traffic noise and waist size, with a 0.21 cm increase for every additional 5-decibel (dB) increase in exposure, although this was only significant among women.
Similarly, there was a link to waist:hip ratio, with a change of 0.16 for every 5 dB increase in noise exposure to road traffic; this association was stronger in men. Larger waist was significantly associated with exposure to any of the three sources of noise, but the link was strongest for aircraft noise; a larger waist:hip ratio was associated with road traffic and aircraft noise only.
The more sources of noise pollution a person was exposed to at the same time, the greater their risk of central obesity seemed to be. Age was an influential factor, with associations between central obesity and road traffic noise only found for those below the age of 60.
Since the study was observational, no definitive conclusions could be drawn about cause and effect.
However, they suggests that noise exposure may be an important physiological stress
or and bump up the production of the hormone cortisol, high levels of which are thought to have a role in fat deposition around the middle of the body.
The study is published online in Occupational and Environmental Medicine.