Air pollution may trigger Alzheimer's-like brain changes and speed memory decline in older adults, a new study suggests.
Previous research has implied that exposure to fine particle air pollution increases the risk of Alzheimer's disease and other types of dementia, but it wasn't clear how this type of pollution affects the brain and memory.
"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 researcher Andrew Petkus. He's an assistant professor of clinical neurology at the University of Southern California's Keck School of Medicine.
"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," Petkus explained in a university news release.
The study included nearly 1,000 women, aged 73 to 87, who had brain scans five years apart. The researchers also assessed information about where the women lived and environmental data from those locations to estimate the women's exposure to fine particle pollution.
The results showed that women who were exposed to higher levels of fine particle air pollution had more Alzheimer's-like changes in brain structure and greater memory declines than those with less exposure to such pollution. But the study only showed an association, and couldn't prove that air pollution caused brain changes or memory declines.
Alzheimer's is the sixth leading cause of death in the United States. There's no cure or treatment.
"This study provides another piece of the Alzheimer's disease puzzle by identifying some of the brain changes linking air pollution and memory declines. Each research study gets us one step closer to solving the Alzheimer's disease epidemic," Petkus said.
Fine particle air pollution - which is inhaled easily, and reaches and accumulates in the brain - has been linked with asthma, heart disease, lung disease and premature death. These tiny air particles come from industrial production, forest fires or vehicles, according to the U.S. Environmental Protection Agency.
The findings were published Nov. 20 in the journal Brain.