Some of the health risks of inhaling fine and ultrafine pollutant particles are well-established, such as asthma, lung cancer, and, most recently, heart disease. But a growing body of evidence suggests that such exposure can also harm the brain, accelerating cognitive aging, and may even increase risk of Alzheimer's disease and other forms of dementia. The link between air pollution and dementia remains controversial—even its proponents warn that more research is needed to confirm a causal connection and work out just how the particles might enter the brain and make mischief there. But a growing number of epidemiological studies from around the world, new findings from animal models and human brain imaging studies, and increasingly sophisticated techniques for modeling PM2.5 exposures have raised alarms. Indeed, in an 11-year epidemiological study to be published next week in Translational Psychiatry, University of Southern California (USC) researchers will report that living in places with PM2.5 exposures higher than the Environmental Protection Agency's standard of 12 μg/m3 nearly doubled dementia risk in older women. If the finding holds up in the general population, air pollution could account for roughly 21% of dementia cases worldwide, says the study's lead author, epidemiologist Jiu-Chiuan Chen of the Keck School of Medicine at USC.
- ↵* in Los Angeles, California