Air Pollution May Contribute to Alzheimer's and Dementia

University of Southern California Professor Jiu-Chiuan Chen writes in the Chicago Sun-Times that his team's latest research indicates that older women who reside in locations with high levels of air pollution suffered memory loss and Alzheimer's-like brain contraction. He says these and other findings suggest that reducing human exposure to PM2.5 or soot can help avoid this risk factor for dementia. "We have been investigating whether PM2.5 may accelerate the brain's aging processes at the preclinical stage — the 'silent' phase of the disease before any symptoms of Alzheimer's disease and related dementias appear," Chen explains. Older women's likelihood of developing clinically significant cognitive impairment nearly doubled if they had lived in places with outdoor PM2.5 levels exceeding the U.S. Environmental Protection Agency's standard. The latest work monitored 712 women, average age 78, who did not have dementia at the start of the study and who had magnetic resonance imaging (MRI) brain scans five years apart. Subjects were more likely to exhibit brain shrinkage similar to that seen in patients with Alzheimer's. Comparing the MRIs of older women from locations with high levels of PM2.5 to those with low levels showed a 24 percent higher dementia risk over five years. "Because the silent phase of dementia is thought to start decades before the manifestation of symptoms, findings from our recent studies raise concerns that air pollution exposures during mid to early life may be equally or even more important than late-life exposure," Chen warns.