Exposure to loud environmental noise might increase the risk of heart attacks and strokes by fueling the activity of a brain region involved in stress response. This response in turn promotes blood vessel inflammation, according to preliminary research to be presented this week in Chicago at the American Heart Association’s Scientific Sessions 2018.
The findings reveal that people with the highest levels of chronic noise exposure – such as highway and airport noise – had an increased risk of suffering cardiovascular events such as heart attacks and strokes, regardless of other risk factors known to increase cardiovascular risk.
The results of the study offer much-needed insight into the biological mechanisms of the well-known, but poorly understood, linkage between cardiovascular disease and chronic noise exposure.
Noise Exposure and Cardiovascular Disease
Researchers at Massachusetts General Hospital examined the link between noise exposure and major cardiovascular events, such as heart attacks and strokes, among 499 people (average age 56 years), who had simultaneous PET and CT scan imaging of their brains and blood vessels. All participants were free of cardiovascular illness and cancer at baseline.
Using PET and CT images, the researchers assessed the activity of the amygdala – an area of the brain involved in stress regulation and emotional responses. To capture cardiovascular risk, the researchers examined the participants’ medical records following the initial imaging studies. Of the 499 participants, 40 experienced a cardiovascular event (e.g., heart attack or stroke) in the five years following the initial testing.
To gauge noise exposure, the researchers used participants’ home addresses and derived noise level estimates from the Department of Transportation’s Aviation and Highway Noise Map.
Individuals with the highest levels of noise exposure had higher levels of amygdalar activity and more inflammation in their arteries. Notably, these people also had a greater than three-fold risk of suffering a heart attack or a stroke and other major cardiovascular events, compared with people who had lower levels of noise exposure. That risk remained elevated even after the researchers accounted for other confounding cardiovascular and environmental risk factors, including air pollution, high cholesterol, smoking and diabetes.
These findings should encourage clinicians to consider chronic exposure to high levels of ambient noise as an independent risk factor for cardiovascular disease. Further, patients and their physicians should consider chronic noise exposure when assessing cardiovascular risk and may wish to take steps to minimize or mitigate such chronic exposure, such as use of hearing protection, noise abatement and periodic hearing tests to monitor any changes in hearing sensitivity.
A summary of the research cited above can be found here.