Noise pollution linked to love handles, study finds

John Hopton for – @Johnfinitum
Scientists studying residents in Stockholm, Sweden have found a link between noise pollution from transport and a larger waist line – an apparent example of the ways in which stress can quietly seep into our lives and affect our wellbeing.
The “spare tire” around the midriff is one of the more dangerous areas a person can carry excess weight, and has links to diabetes, among other concerns. Since this risk is well known by health professionals, people take plenty of measures to reduce their waistline, such as dietary changes and exercise. But moving to a home not located close to noisy planes, trains and automobiles? Most are unlikely to have thought of that.
The researchers assessed how much road traffic, rail, and aircraft noise 5075 people living in five suburban and rural areas around Stockholm had been exposed to since 1999.
All the participants had been part of the Stockholm Diabetes Prevention Program (1992-1998), which aimed to look at risk factors for the development of diabetes and how best to prevent it.
The waist is most susceptible and most problematic
Between 2002 and 2006, when they were aged between 43 and 66, they completed a detailed questionnaire covering lifestyle, current state of health, levels of psychological distress, insomnia and job strain. They were also asked about environmental noise pollution from road traffic, trains, and planes.
They underwent a medical, which included blood pressure and a test for diabetes, as well as measures of central body fat (waist and hips and the waist:hip ratio), plus overall obesity, weight and height to define the body mass index (BMI).
Although the effects on overall BMI were not significant, when it came to waist size specifically there was a notable effect. Risk of a larger waist was found to be 25 percent for people exposed to only one of the three possible noise sources, and almost doubled for those exposed to all three.
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 researchers therefore assessed that the risk was cumulative.
There was some variation between gender and type of weight gain. For example, most significant in women was an association between road traffic noise and waist size, with a 0.21 cm increase for every additional 5 decibels (dB) increase in exposure. Meanwhile, for men, there was a link to waist-to-hip ratio, with a change of 0.16 for every 5 dB increase in noise exposure to road traffic.
It is also worth noting that age was a factor, with associations between central obesity and road traffic noise only found for those below the age of 60.
Other potential influences, such as socio-economic factors and ambient air pollution from local traffic, were accounted for.
Effects on stress and sleep
Although no definite conclusion as to the reason why noise pollution would cause weight gain, the researchers’ assumption is that the effects of noise pollution on stress levels and sleep quality result in increased waistlines. Stress increases production of the hormone cortisol, high levels of which are thought to have a role in fat deposition around the middle of the body.
“This may explain why the effects of noise were mainly seen for markers of central obesity, such as waist circumference and waist-hip ratio, rather than for generalised obesity, measured by BMI,” the researchers wrote.
Traffic noise from any of the three sources may also affect metabolic as well as cardiovascular functions, through sleep disturbance, they suggest, altering appetite control and energy expenditure.
The findings were published in the journal, Occupational & Environmental Medicine.
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