Exposure to traffic noise could increase risk of type 2 diabetes

Stress caused by frequent exposure to road traffic noise could increase the risk of type 2 diabetes, according to new research.
The study, published in the journal Occupational and Environmental Medicine, suggests that people who are exposed to the stress of traffic noise on a regular basis are more likely to be obese, which increases the risk of type 2 diabetes.
The researchers recruited thousands of men and women from Stockholm. The study, which was conducted over a four-year period (2002 to 2006), discovered that two-thirds of participants were regularly exposed to traffic noise, while five per cent of participants had been exposed to the noise of trains.
There was no relationship between traffic noise exposure and BMI, but there was a link between traffic noise and waist size. For every five decibels of exposure over 45dB, participants had, on average, a 0.21cm increase in waist size.
Stress increases the risk of obesity by slowing down the metabolism, which means people burn fewer calories while stressed. People exposed to higher levels of stress, therefore, are more likely to develop obesity, which significantly increases the risk of several other health conditions, including type 2 diabetes, heart disease, stroke, and some forms of cancer.
Stress also increases the production of the hormone cortisol. When we become stressed, our bodies secrete more cortisol, which instigates the “fight or flight” response. One of the effects of this response is a distribution of stored glucose into the blood, where it can be used more immediately. The increased levels of glucose demand more insulin. Over time, this increases the risk of insulin resistance and type 2 diabetes.
For people who have already been diagnosed with type 2 diabetes, or for people with prediabetes, stress leads to hyperglycemia, which can be treated with moderate exercise or medication.
“There are still very few studies investigating the association between traffic noise and metabolic markers, such as BMI and waist circumference, and our results must therefore be interpreted with caution,” said researcher Charlotta Eriksso, an epidemiologist as Stockholm’s Centre for Occupational and Environmental Medicine.
Professor Göran Pershagen said: “Increased waist circumference (or central obesity) is an established risk factor for diabetes type 2 and a range of cardiovascular diseases. Consequently, the public health implications of our findings are potentially significant given the wide-spread and increasing exposure to traffic noise.”
Professor Pershagen stressed that, while the findings were conducted in Sweden on Swedish participants, they are entirely relevant to Britai, and many other parts of the world.