Unexpected Factor Can Increase Your Dementia Risk

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Son with his senior father
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If you live in a place with high pollution levels, your risk of developing dementia might be substantially increased, according to a recent study.

Researchers at the University of California, San Francisco, found that among older Americans with cognitive impairment, those living in the most polluted areas had a 10% increased probability of a PET scan showing amyloid plaques when compared with peers who live in the least polluted areas.

The study — which was recently published in JAMA Neurology — adds to earlier research that has found a link between pollution and a higher risk of dementia. Sources of such pollution include cars, factories, power plants and forest fires.

The researchers looked at positron emission tomography (PET) scans of more than 18,000 seniors from across the country. The average age of the seniors was 75, and all had dementia or mild cognitive impairment.

Given that about 5.8 million people over 65 have Alzheimer’s disease, high exposure to microscopic airborne particles may be a factor in tens of thousands of cases, the researchers say.

One of the study authors, Leonardo Iaccarino, says daily exposure to PM2.5 — atmospheric particulate matter that has a diameter of less than 2.5 micrometers — could provoke a chronic inflammatory response, even at levels considered to be normal. He says:

“Over time, this could impact brain health in a number of ways, including contributing to an accumulation of amyloid plaques.”

Amyloid plaques form in the brain when protein pieces called beta-amyloid clump together. They are believed to cause cell death and tissue loss in the brain of someone with Alzheimer’s disease.

The American Lung Association releases an annual ranking of the metro areas that are most polluted by short-term particle pollution as measured by 24-hour PM2.5 levels. According to the 2020 ranking, the latest available, these cities are all in the Western U.S.:

  1. Fresno-Madera-Hanford, California
  2. Bakersfield, California
  3. San Jose-San Francisco-Oakland, California
  4. Fairbanks, Alaska
  5. Yakima, Washington
  6. Los Angeles-Long Beach, California
  7. Missoula, Montana
  8. Redding-Red Bluff, California
  9. Salt Lake City-Provo-Orem, Utah
  10. Phoenix-Mesa, Arizona

The American Lung Association report found that overall, nearly half of the U.S. population — 150 million people — are living with and breathing unhealthy air.

For tips on preventing dementia, check out “7 Lifestyle Changes That May Help Prevent Dementia.”

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