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Air pollution may do more than damage the environment — it could screw up the long-term health of your brain, too.
New research published in the Annals of Neurology found that people who were exposed to more air pollution had “older” brains than those who regularly breathed cleaner air. In the study, scientists conducted brain scans on more than 1,400 older women to evaluate how much gray matter (which processes information) and white matter (which helps nerves in the brain communicate) they had in their brains.
They also analyzed air pollution data to estimate how much pollution, in the form of tiny particles that can penetrate the lungs, the women were exposed to from 1999 to 2006.
Scientists discovered that for each 3.49 micrograms per cubic centimeter of air pollution the women were exposed to, they had a 6.23 cubic centimeter decrease in white matter. In layman’s terms, that’s the equivalent of up to two years of brain aging.
Here’s why that’s so troubling: White matter loss has been linked with cognitive impairment, dementia, and other serious neurological diseases, says study co-author Gregory Wellenius, Sc.D., an associate professor of epidemiology at Brown University School of Public Health.
Our brains lose white matter as we age, but, if that loss is accelerated, you could run the risk of developing these complications earlier in life.
Lead study author Jiu-Chiuan Chen, M.D., Sc.D., an associate professor of preventive medicine at the Keck School of Medicine at the University of Southern California tells Yahoo Health that he found it “perplexing” that pollution didn’t impact the brain’s grey matter as well, but says more research on a younger group of people may find a decrease.
Previous research has linked living in areas of with higher levels of air pollution to worse performance on tests of cognitive function and faster rates of cognitive decline, but Chen says the new findings are important because they suggest pollution can actually alter the structure of our brains.
Unfortunately, scientists don’t know why this happens. “We know from earlier studies that exposure to air pollution can lead to inflammation in the brain, change blood flow to the brain, and damage specific regions of the brain,” Wellenius tells Yahoo Health. “However, more research is needed to really understand how air pollution damages our brains.”
Air pollution causes one in eight global deaths, according to the World Health Organization, which estimates that around 7 million people around the world died in 2012 as a result of air pollution exposure.
But air pollution doesn’t just stop at brain damage; It’s also linked to heart disease. Research published in the journal Circulation in 2010 found that longer-term exposure to air pollution can reduce a person’s life expectancy by several months to a few years. However, the research also discovered those harmful effects can be reduced in a few years when a person is exposed to better air quality.
Chen says that more research is needed before scientists can say whether the impact on our brains is reversible in the same way that it is on heart health. And, unfortunately, he’s not convinced that it is: “To my knowledge, there is no evidence for white matter regeneration after damages caused by air pollution exposure.”
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