Studies increasingly find links between higher concentrations of certain pollutants and the prevalence of dementia.
For years, the two patients had come to the Penn Memory Center at the University of Pennsylvania, where doctors and researchers follow people with cognitive impairment as they age, as well as a group with normal cognition.
Both patients, a man and a woman, had agreed to donate their brains after they died for further research. “An amazing gift,” said Edward Lee, the neuropathologist who directs the brain bank at the university’s Perelman School of Medicine. “They were both very dedicated to helping us understand Alzheimer’s disease.”
The man, who died at 83 with dementia, had lived in the Center City neighborhood of Philadelphia with hired caregivers. The autopsy showed large amounts of amyloid plaques and tau tangles, the proteins associated with Alzheimer’s disease, spreading through his brain.
Researchers also found infarcts, small spots of damaged tissue, indicating that he had suffered several strokes.
The man had lived a few blocks from Interstate 676, which slices through downtown Philadelphia. The woman had lived a few miles away in the suburb of Gladwyne, Pennsylvania, surrounded by woods and a country club.
The amount of air pollution she was exposed to — specifically, the level of fine particulate matter called PM2.5 — was less than half that of his exposure. Was it a coincidence that he had developed severe Alzheimer’s while she had remained cognitively normal?
With increasing evidence that chronic exposure to PM2.5, a neurotoxin, not only damages lungs and hearts but is also associated with dementia, probably not.
“The quality of the air you live in affects your cognition,” said Lee, the senior author of a recent article in JAMA Neurology, one of several large studies in the past few months to demonstrate an association between PM2.5 and dementia.
Scientists have been tracking the connection for at least a decade. In 2020, the influential Lancet Commission added air pollution to its list of modifiable risk factors for dementia, along with common problems like hearing loss, diabetes, smoking, and high blood pressure.
Yet such findings are emerging when the federal government is dismantling efforts by previous administrations to continue reducing air pollution by shifting from fossil fuels to renewable energy sources.
“‘Drill, baby, drill’ is totally the wrong approach,” said John Balmes, a spokesperson for the American Lung Association who researches the effects of air pollution on health at the University of California-San Francisco.
“All these actions are going to decrease air quality and lead to increasing mortality and illness, dementia being one of those outcomes,” Balmes said, referring to recent environmental moves by the White House.
