A comprehensive study revealed that exposure to traffic noise during the night is clearly associated with higher levels of cholesterol and blood fats in adults who live near busy roads, placing urban noise among the metabolic risk factors linked to heart disease and diabetes.
“Night noise and cholesterol”
The researchers analyzed data from more than 272,000 people, matched their home addresses to road noise levels at night, and then linked this to the results of detailed blood tests that included 155 different indicators.
The results showed that a rise in noise levels above about 50 dB at night was accompanied by a gradual increase in lipid indices, and these elevations increased significantly at 55 dB and above, indicating the existence of a threshold at which a potential biological effect begins.
Increases in total cholesterol and blood fats have been reported, including “LDL” (low-density cholesterol), which is associated with plaque buildup in the arteries.
Sleep disturbance likely plays a key role in this, as nighttime noise activates stress responses even without being fully awake, increasing hormones such as cortisol that may stimulate the liver to produce more cholesterol.
Although the changes per person were small, the potential impact on public health could be significant given the prevalence of noise, with about 109 million Europeans living at noise levels considered unhealthy.
After taking into account other factors such as air pollution, smoking and weight, the association between noise and fat indexes remained.
The study, published in Environmental Research, suggests that reducing night-time noise by reducing traffic, improving road surfaces, insulating windows, and placing bedrooms away from the street may reduce potential metabolic effects.
