According to a study published in the February 21, 2024 online issue, people who are exposed to high levels of traffic-related air pollution are more likely to have higher amounts of amyloid plaques in their brains that lead to Alzheimer’s disease after death. are connected to Neurology®Medical Journal of the American Academy of Neurology. The researchers looked at the finer particles, PM2.5which consists of airborne pollutant particles less than 2.5 microns in diameter.

This research does not prove that air pollution causes more amyloid plaques in the brain. It shows only one association.

“These findings add to the evidence that fine particles from traffic-related air pollution affect the amount of amyloid plaques in the brain,” said study author Anne Hewls, Ph.D., of Emory University in Atlanta. said “Further research is needed to investigate the mechanisms behind this link.”

For the study, researchers examined brain tissue from 224 people who agreed to donate their brains at the time of death to advance dementia research. People died at an average age of 76.

The researchers looked at traffic-related air pollution exposure based on people’s home addresses in the Atlanta area at the time of death. Traffic related PM2.5 In urban areas such as the metro-Atlanta area where most donors lived, concentrations are a major source of environmental pollution. The average exposure level in the year before death was 1.32 micrograms per cubic meter (µg/m).3) and 1.35 µg/m3 In the three years before death.

The researchers then compared pollution exposure to measures of Alzheimer’s disease symptoms in the brain: amyloid plaques and tau tangles. They found that people who were more exposed to air pollution one and three years before death were more likely to have higher levels of amyloid plaques in their brains. Individuals with 1 µg/m3 High PM2.5 Exposure in the year before death was almost twice as likely to have high levels of plaque, while those with high exposure in the three years before death were 87% more likely to have high levels of plaque.

The researchers also looked at whether variations in the main gene linked to Alzheimer’s disease, APOE e4, had any effect on the relationship between air pollution in the brain and Alzheimer’s symptoms. They found that the strongest link between air pollution and Alzheimer’s symptoms was in people who did not carry the gene variant.

“This suggests that environmental factors such as air pollution may be an important factor in Alzheimer’s disease in patients whose disease cannot be explained by genetics,” Havels said.

A limitation of the study is that the researchers only had people’s home address at the time of death to measure air pollution, so exposure to pollution may have been misclassified. The study also included predominantly white people who were highly educated, so the results may not be representative of other populations.

This study was supported by the HERCULES Pilot Project, the Goizueta Alzheimer’s Disease Research Center and the Rollins School of Public Health Dean’s Pilot and Innovation Grant.