Researchers assessed how much road traffic, rail, and aircraft noise 5075 people living in five suburban and rural areas around Stockholm, Sweden, had been exposed to since 1999.
The researchers calculated that well over half (62%, 3127) had been regularly exposed to road traffic noise of at least 45 decibels (dB) while one in 20 had been exposed to similar levels of noise from trains. A further 1108 had been exposed to aircraft noise of more than 45 dB.
In all, just over half (54%, 2726) had been exposed to one source of traffic noise; 15% (740) to two sources; and 2% (90) to all three. Around a third (30%, 1519) had been exposed to levels below 45 dB, which were not considered to be harmful.
The research found as association between road traffic noise and waist size, with a 0.21 cm increase for every additional 5 dB increase in exposure, although this was only significant in women.
Similarly, a link to waist:hip ratio, with a change of 0.16 for ever 5 dB increase in noise exposure to road traffic; this association was stronger in men/
A 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.
The heightened risk of a larger waist rose from 25% among those exposed to only one source to almost double for those exposed to all three sources.
Central obesity is thought to be one of the most harmful types of fat deposition around the body.
Dr Andrei Pyko, lead author of the study at Karolinska Institute in Sweden, said: “Traffic noise is a common and increasing environmental exposure, primarily due to ongoing urbanization and growth of the transport sector.
“Road traffic is the dominating source, followed by railway and aircraft noise. Health effect related to traffic noise are widespread and span from annoyance, sleep disturbances and changes in stress hormone levels to adverse effects on the cardiovascular system.
“Our results suggested associations with waist circumference primarily in the age group below 60 years.”