FollowA new study published in the May 2015 issue of Stroke shows that air pollution does not only damage the environment, but also the human brain. Scientists have found that long-term exposure to polluted air affects the brain in negative ways, causing neurological diseases such as memory problems, dementia, strokes and premature aging of the brain.
Lead researcher Elissa Wilker, a researcher in the cardiovascular epidemiology research unit at Beth Israel Deaconess Medical Center in Boston, and her team of professionals examined a total of 943 adults (men and women) who lived in the New England region. The participants had to have good health and be at least 60 years old.
The scientists used magnetic resonance imaging (M.R.I.) to look at the brains of their subjects, then compared the images with air pollution levels found where each of the participants lived.
They discovered that an increase of 2 micrograms per cubic meter in fine-particle pollution caused the brain to reduce its volume by 0.32%. Though it might not sound like a lot at first, author Elissa H. Wilker informs us that “the magnitude of association that we observed for brain volume was similar to approximately one year of brain ageing”.
Fine-particle pollution is a common type of pollution that comes primarily from car exhaust and the burning of wood and coal. It is known to effortlessly enter the lungs and bloodstream.
The same increase (2 micrograms per cubic meter) of fine-particle pollution is also believed to increase the changes of having a “silent stroke” by 45%. The “silent stroke”, as the researchers called it, can be seen on brain scans. but doesn’t typically cause symptoms (the person affected feels no symptoms but receives some of the negative effects of a stroke.).
“Silent stroked” have been linked to poorer cognitive function and dementia, and they also increases the risk of having overt strokes in the future.
Wilker concluded: “we found that people who live in areas where there are higher levels of air pollution had smaller total cerebral brain volume and were more likely to have evidence of covert brain infarcts”
She added that “long-term exposure to air pollution showed harmful effects on the brain in this study, even at low levels, particularly with older people and even those who are relatively healthy”.
Though the likelihood of a connection is very strong, an explanation is yet to be found as Wilker went on to say that “the mechanisms through which air pollution may affect brain aging remain unclear, but systemic inflammation resulting from the deposit of fine particles in the lungs is likely important”.
She also pointed out that this is the first study to explore the issue (previous studies linking pollution to neurological diseases focused on the brains of children, not adults), it was done at one specific point in time (between 1995 and 2005) and that it does not offer undeniable proof of a cause-and-effect relationship between air pollution and brain changes as brain shrinkage is caused by the loss of neurons, a typical process for an aging brain.
Image Source: nationalgeographic.com
