A causal mechanism explaining how noise causes dementia?

Photo credit: Kindel Media

by Daniel Fink, MD, Chair, The Quiet Coalition

In 2020 Weuve et al. reported an association between community noise exposure and cognitive impairment including dementia. The paper didn’t state that noise caused dementia, only that there was an association between long-term community noise exposure and dementia. As one of my mentors pointed out when I was in training, correlation isn’t causation. Research showing correlations between exposures or behaviors and various diseases may provide clues about causation, but that’s all they do.

A recent report in JAMA Open Network and an accompanying editorial, combined with older articles, may help explain a causal relationship between long-term community noise exposure and dementia.

It has been known for a long time that noise is stressful. More recently, the nuclear medicine research group at the Massachusetts General Hospital reported that stress caused activation of the amygdala, the part of the brain associated with processing emotions, and this in turn was associated with vascular inflammation, cardiovascular disease, and increased mortality. Stroke was among the cardiovascular diseases included in this study. In 2020, transportation noise was specifically shown to be associated with major adverse cardiovascular events, which includes stroke.

There is a strong link between cardiovascular disease and dementia, and many experts think that dementia is largely a vascular disease. From the Framingham study, we know that reducing cardiovascular disease also reduces the incidence of dementia.

If noise causes stress, and stress causes vascular inflammation which in turn causes cardiovascular disease, that may be the causal mechanism explaining how long-term community noise exposure causes dementia.

Reducing transportation noise and other sources of unwanted noise might reduce dementia. Wouldn’t that be wonderful?

As we have been saying for some years now, a quieter world will be a better and healthier world for all.

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