Air pollution may lead to dementia in older women.

A new study shows that air pollution by tiny, dirty airborne particles called PM2.5 invade the brain and wreak havoc causing dementia in older women. The study published in the Nature journal Translational Psychiatry, adds to an emerging body of research from around the world that links air pollution to dementia. The offending pollutants known as PM2.5 are fine, inhalable particles with diameters 2.5 micrometers or smaller. A human hair is about 70 micrometers in diameter, making it 30 times larger than the largest PM2.5. Scientists and engineers found that older women who live in places with fine particulate matter exceeding the U.S. Environmental Protection Agency's standard are 81 percent more at risk for global cognitive decline and 92 percent more likely to develop dementia, including Alzheimer's. These microscopic particles generated by fossil fuels get into our body directly through the nose into the brain and cells in the brain treat these particles as invaders and react with inflammatory responses, which over the course of time, appear to exacerbate and promote Alzheimer's disease. The adverse effects were stronger in women who had the APOE4 gene, a genetic variation that increases the risk for Alzheimer's.