How does environmental noise contribute to heart disease risk?
The idea that heart disease may be caused by traffic noise could strike you as unlikely at first.
Although healthcare providers will focus on traditional risk factors when they diagnose, prevent, and treat heart disease, ever more evidence is supporting the notion that risk factors in the physical environment may contribute to heart disease, as well.
Several studies have demonstrated an association between an increased risk of heart disease and traffic noise. However, these studies have previously been unable to pinpoint the mechanisms that may be active in noise-induced heart disease.
Now, the Journal of the American College of Cardiology has published a review investigating the potential mechanisms by which environmental noise may contribute to heart disease.
What mechanism drives the association?
To understand what mechanism may drive the association between environmental noise and heart disease, researchers from the Department of Internal Medicine at University Medical Center Mainz of Johannes Gutenberg University in Germany have conducted a review of the available scientific literature.
They assessed recent evidence of the link between heart disease and environmental noise and reviewed studies that investigated how the nonauditory effects of noise might impact the cardiovascular system.
Also, they reviewed studies on the effects of noise on the nervous system and those investigating adverse effects of noise on animals as well as humans.
From the evidence evaluated in their review, the study authors suggest that the mechanism at play could be a stress response in the nervous system that is activated by exposure to noise. The stress response prompts a surge of hormones, which damages the blood vessels.
The authors also connect noise with oxidative stress — an imbalance between the production of free radicals and the body's ability to nullify their effects — and problems with the blood vessels, nervous system, and metabolism.
These associations, the researchers conclude, add weight to the idea that traffic or aircraft noise contributes to hypertension, diabetes, and other risk factors for heart disease.
New noise reduction strategies are needed
Having assessed some of the existing strategies used around the world to lower the impact of noise, the researchers propose that low-noise tyres and air traffic curfews could make positive contributions to environmental noise reduction.
They emphasize that new noise reduction strategies are sorely needed.
"[A]s the percentage of the population exposed to detrimental levels of transportation noise are rising, new developments and legislation to reduce noise are important for public health."
Lead study author Thomas Münzel, director of the Department of Internal Medicine