Study finds air pollution linked to signs of Alzheimer's disease in brain tissue

The study was published this week in the journal neurology, researchers investigated the association between the concentration of ambient air pollution and signs of Alzheimer's disease in the human brain. They say people exposed to high concentrations of fine particulate matter air pollution, also known as PM2.5, At least one year before death, higher levels of plaque — Abnormal clusters of protein fragments that accumulate between nerve cells. This is a sign of Alzheimer's disease in brain tissue. The study also found a strong link between environmental pollution and signs of Alzheimer's disease in people who are not genetically predisposed to the disease.

“This suggests that environmental factors, such as air pollution, may contribute to Alzheimer's disease, especially in patients whose disease cannot be explained by genetics,” said the study's lead author, Emory University Assistant Professor Anke Huels said. of public health. Although the study does not prove that air pollution causes Alzheimer's disease, it did find a link between exposure to certain types of pollution and signs of Alzheimer's disease.

Researchers examined tissue from 224 donors in the Atlanta metropolitan area who volunteered to donate their brains for research before they died.

“Donors who lived in areas with especially high levels of traffic-related air pollution had more plaque associated with Alzheimer's disease at the time of death than donors who lived in areas with lower air pollution levels,” Huels said. said.

She added that what this study tells researchers is that exposure to high levels of pollution increases the risk of Alzheimer's disease.

More than half of the donors had a gene known as APOE, which is the strongest genetic risk factor for Alzheimer's disease. But for donors who don't yet have a genetic predisposition, researchers found a strong link between traffic-related air pollution and signs of Alzheimer's disease.

It has long been known that concentrations of PM2.5 can cause short-term respiratory illnesses. it is, particles are very small Because they are less than 2.5 microns in diameter, they enter the bloodstream after inhalation. According to , inhaling smoke can also irritate your sinuses, throat, and eyes. Centers for Disease Control and Prevention. In more severe cases, exposure is associated with cardiovascular effects, including heart attacks and strokes, as well as lung cancer and impaired cognitive function.

Gaurav Basu, director of education and policy at Harvard University's Center on Climate, Health and the Environment, said the study shines a spotlight on the dangers air pollution poses to the brain.

“We think a lot about air pollution in our lungs, but it's important to keep our brains at the forefront of conversations about how air pollution affects our health,” Bass says.

While the study primarily looked at the brains of white, college-educated men, Bass said poorer communities and communities of color are more exposed to particulate matter and traffic-related pollution. . This is because highways and roadways are intentionally built in their communities.

“This pollution doesn't affect everyone the same way,” Bass said. “Vehicle air pollution is fundamentally a health equity issue.”

Heather Snyder, vice president of medical and scientific affairs at the Alzheimer's Association, said more research is needed to determine the exact link between traffic-related air pollution and brain changes caused by Alzheimer's disease.

“We know that Alzheimer's disease is a complex disease, and there are likely a combination of factors that influence a person's lifetime risk,” Snyder told the Post in an email. “Avoiding exposure to air pollution is a risk factor that some people can change, but others cannot or cannot change easily.”

This research also The latest information from a growing body of literature reveals The relationship between air pollution and cognitive decline.emerging the study They also found that exposure to traffic-related particulate matter is correlated with reduced cortical thickness and thinner gray matter in the brain, which can affect information processing, learning and memory. did. Experts pointed to growing evidence linking exposure to air pollution to cognitive decline, mood disorders and Alzheimer's disease diagnoses.

For Huels, the best way to reduce exposure is to make personal changes, such as limiting time outdoors when air pollution levels are high and wearing a mask when necessary. . He said other changes, such as driving electric cars and using public transport, can also help reduce air pollution.

“Really reducing exposure to air pollution requires political decisions and changes,” Huels said. “There is really no safe or healthy level of general air pollution or traffic-related air pollution.”