Exposure to traffic noises may up obesity risk: Study

People who are exposed to road traffic noise for prolonged periods may be at increased risk of obesity, a study has found.

The study, published in the journal Environment International, was based on data from 3,796 adults.

"Our analysis shows that people exposed to the highest levels of traffic noise are at greater risk of being obese," said Maria Foraster, from Barcelona Institute for Global Health (ISGlobal) in Spain.

"For example, we observed that a 10-decibel increase in mean noise level was associated with a 17 per cent increase in obesity," said Foraster.

Researchers also analysed exposure to noise generated by aircraft and railway traffic and found no significant associations except in the case of long-term exposure to railway noise, which was associated with a higher risk of overweight but not of obesity.

The methodology and design of the study were chosen to allow the authors to look at the data from two different perspectives.

Cross-sectional analysis was used to study the participant population at a specific time point in the study and to examine more objective measures.

The longitudinal design, on the other hand, allowed the authors to evaluate how the risk of obesity evolved over the study period.

The associations with traffic-related noise pollution were consistent in both cases. Overweight was only associated with exposure to traffic-related noise in the cross-sectional analysis.

Researchers found no association between noise exposure and body mass index measured continuously throughout the longitudinal analysis.

"Our study contributes additional evidence to support the hypothesis that traffic-related noise affects obesity because the results we obtained in a different population were the same as those reported by the authors of earlier studies," said Foraster.

Sustained exposure to noise pollution is a widespread public health problem that is more serious than previously thought, researchers said.

Noise generates stress and affects our sleep. It alters hormone levels and increases blood pressure. Moreover, among other effects, sleep disturbance deregulates glucose metabolism and alters the appetite.

"In the long term, these effects could give rise to chronic physiological alterations, which would explain the proven association between persistent exposure to traffic-related noise and cardiovascular disease or the more recently discovered associations with diabetes and obesity," said Foraster.

"Our findings suggest that reducing traffic-related noise could also be a way of combating the obesity epidemic," she said.