Improving Air Quality Reduces Dementia Risk

Previous reports have linked long-term air pollution exposure with accumulation of Alzheimer’s disease-related brain plaques, but this is the first accumulated evidence that reducing pollution, especially fine particulates in the air and pollutants from the burning of fuel, is associated with lower risk of all-cause dementia and Alzheimer’s disease. Both increasing levels of air pollution and increasing cases of dementia are worldwide public health crises. While research has linked air quality and cognition previously, these new data at AAIC 2021 explore how air pollutants might impact dementia and what reducing them might mean for long-term brain health.

What’s exciting is we’re now seeing data showing that improving air quality may actually reduce the risk of dementia.

– Claire Sexton, DPhil, Alzheimer’s Association Director of Scientific Programs and Outreach

Among the key findings are:

• Reduction of fine particulate matter (PM2.5) and traffic-related pollutants (NO2) per 10% of the Environmental Protection Agency’s (EPA) current standard over 10 years was associated with 14% and 26% reductions in dementia risk, and slower cognitive decline, in older U.S. women. These benefits occurred in women regardless of their age, level of education, the geographic region where they lived and whether they had cardiovascular disease.
• Reduction of PM2.5 concentration over 10 years was associated with a reduced risk of all-cause dementia in French individuals by 15% and of Alzheimer’s disease by 17% for every microgram of gaseous pollutant per cubic meter of air (µg/m3) decrease in PM2.5.
• Long-term exposure to air pollutants was associated with higher beta amyloid levels in the blood in a large U.S. cohort, showing a possible biological connection between air quality and physical brain changes that define Alzheimer’s disease.

“We’ve known for some time that air pollution is bad for our brains and overall health, including a connection to amyloid buildup in the brain,” said Claire Sexton, DPhil, Alzheimer’s Association director of scientific programs and outreach. “But what’s exciting is we’re now seeing data showing that improving air quality may actually reduce the risk of dementia. These data demonstrate the importance of policies and action by federal and local governments, and businesses, that address reducing air pollutants.”