It has been known for a long time that air pollution raises the risk of stroke even when pollution is found in moderate levels. A new study shows that after a long-term exposure to polluted air brain structures can be damaged and cognitive functions can be impaired in the case of middle-aged and older adults.
The study was conducted by scientists from Boston University School of Medicine and Beth Israel Deaconess Medical Center. 943 healthy adults were examined. They came from New England and were around 60 years old. For the research the scientists used MRI (magnetic resonance imaging) in order to analyze the brain structures of the participants and compare the obtained images with the level of air pollution from the places where the participants lived.
The results of the study indicated that in fine-particle pollution there was an increase of 2 micrograms per cubic meter. This range can be observed in average cities and is linked with a reduction of 0.32% in brain volume. Fine-particle pollution usually comes from car exhaust. According to lead author of the study, Elissa H. Wilker of the cardiovascular epidemiology research unit at Beth Israel Deaconess Medical Center, a reduction of 0.32% represents one year of brain aging.
Wilker does not know in what way pollution exactly harms the brain, but she suspects that the particles which are breathed in cause inflammation. The inflammation which starts in the lungs may afterwards spread to the brain.
The same increased amount of fine-particle pollution is associated with a 46% increased risk of silent strokes or mini-strokes. This type of stroke does not show any symptoms, but it is visible on brain scans. Silent strokes are associated with dementia and poor cognitive function.
Dr. Beate Ritz of the Center for Occupational and Environmental Health at UCLA’s Fielding School of Public Health said that silent strokes do not cause as much harm as larger strokes do, but they are dangerous depending on which part of the brain they occur. Although they do not leave the affected person disabled, they can significantly reduce your health-related quality of life. Ritz also said that they are insidious because in most of the time people are not aware that they are experiencing one:
“You might be a little more dizzy today and then lose a little more vision tomorrow. And people tend to attribute that to aging instead of knowing what happened.”
Image Source: Elephant Journal