PM2.5 Pollution Linked To Brain Atrophy & Memory Decline

"This is the first study to really show, in a statistical model, that air pollution was associated with changes in people's brains and that those changes were then connected with declines in memory performance," said Andrew Petkus, assistant professor of clinical neurology at the Keck School of Medicine at USC.

"Our hope is that by better understanding the underlying brain changes caused by air pollution, researchers will be able to develop interventions to help people with or at risk for cognitive decline."

PM2.5 are fine particles of air pollution that are about 1/30th the width of a human hair coming from factories, traffic exhaust as well as smoke and dust, and their tiny size allows them to remain airborne for long periods of time to reach inside of buildings/homes to be inhaled easily where they can travel to the brain and accumulate. 

PM2.5 fine particle pollution is associated with lung disease, cardiovascular disease, asthma, and premature death; exposure has been suggested in previous research to increase the risk for Alzheimer’s disease and related dementias, but what was not known is whether PM2.5 alters brain structure and accelerates cognitive decline. 

Data was used from 998 women between the ages of 73-87 who had up to 2 brain scans five years apart as part of the landmark Women’s Health Initiative which was launched in 1993 by NIH enrolling over 160,000 women to address questions about heart disease, cancer, and osteoporosis. 

Scans were scored on the basis of similarity to patterns of Alzheimer’s disease by a deep machine learning tool that had been trained via brain scans of those with the disease. Information was also gathered regarding where the women lived and environmental data from the locations to estimate exposure to PM2.5 fine particle pollution. 

After all of the data was combined an association was found between higher exposure to PM2.5 fine particle pollution, brain changes, and memory problems; after adjusting to take into account other factors such as income, education, race, geographic region, and history of smoking the association remained.

"This study provides another piece of the Alzheimer's disease puzzle by identifying some of the brain changes linking air pollution and memory decline. Each research study gets us one step closer to solving the Alzheimer's disease epidemic," Petkus said.