Living in areas with high traffic has several adverse health effects, mostly due to the air pollution generated by vehicles. But even the noise itself is pretty bad for your health, a new study reports.

New research at the University of Oxford and the University of Leicester found that long-term exposure to traffic noise could be a promoter for obesity. People living in such areas had a higher chance of having an increased body mass index and waist circumference, the study explains. This effect was more pronounced in areas with louder traffic noise.

Heavy traffic

“While modest, the data revealed an association between those living in high traffic-noise areas and obesity, at around a 2% increase in obesity prevalence for every 10dB of added noise,” says lead author Dr. Samuel Yutong Cai, a senior epidemiologist at the University of Oxford.

“The association persisted even when we accounted for a wide range of lifestyle factors, such as smoking, alcohol use, physical activity, and diet, as well as when taking into account the socio-economic status of both individuals and the overall area. Air pollution was also accounted for, especially those related to traffic.”

The study worked with data from more than 500,000 people, data which it mined from three European biobanks in the UK, the Netherlands, and Norway.

The authors describe the identified link as ‘modest’ because they uncovered an interplay between traffic noise and indicators of obesity in individuals from the UK and Norway, but not in the Netherlands. By themselves, these results aren’t enough to reliably confirm a cause and effect relationship between the two. However, the authors note that the findings are backed up by previous similar findings in other countries in Europe.

Still, the findings can’t, as of right now, be used as proof that one causes the other. They do, however, offer enough evidence to warrant further research into the topic.

Over 100 million people in the EU live in areas where road traffic noises exceeds 55dB (decibels) in volume, which is the safety threshold set by the EU, the paper notes. This exposure could be a driver of obesity.

“It is well-known that unwanted noise can affect quality of life and disturb sleep,” says co-author Professor Anna Hansell, Director of the University of Leicester’s Centre for Environmental Health and Sustainability.

“Recent studies have raised concerns that it also may influence general health, with some studies suggesting links to heart attacks and diabetes. Road traffic noise may increase stress levels, which can result in putting on weight, especially around the waist.”

Most of our efforts to stay healthy and avoid the extra pounds only work on an individual level — think things like exercise or dieting. And we should definitely keep doing that, as they are still the most effective tools we have against obesity. But policies that reduce traffic noise (or at least, exposure to it) may help further tackle this issue “on a population level,” argues Dr Cai.

“As we emerge and recover from COVID-19, we would encourage the government to look at policies that could manage traffic better and make our public spaces safer, cleaner and quieter,” he adds.

“Air pollution is already a well-known health risk, but we now have increasing evidence that traffic noise is an equally important public health problem. The UK should take this opportunity to think about how we can, as a society, re-organize cities and communities to support our health and reap better health outcomes across the whole population.”

The team is now testing how exposure to other sources of noise, such as that produced by aircraft, influences weight gain.

The paper “Impact of road traffic noise on obesity measures: observational study of three European cohorts” has been published in the journal Environmental Research.