A growing body of evidence in recent years has shown that air pollution is a significant risk factor for the development of dementia in old age. That shouldn’t be a big shock. “When sensitive people inhale polluted air from the outside, very small particles can penetrate the lungs and enter the circulatory system,” Jiu-Chiuan Chen, a neuroscientist at the University of Southern California, told The Daily Beast. “These” toxic “reactions can make the blood-brain barrier leak and damage the brain. It is not very different from how other risk factors, such as smoking, can negatively affect human health, leaving it more susceptible to degenerative diseases such as dementia.
A big question for researchers in recent years has been whether the impact of air pollution on the risk of dementia was permanent – or can this be reversed. New discoveries published in Proceedings of the National Academy of Sciences brings good news: Improved air quality over several years is associated with a reduced risk of dementia in older women.
The findings reinforce suspicions that external contaminants may contribute to accelerating brain aging (which is practically dementia). But more critically, they also show that this aging can be slowed if exposure to these pollutants is reduced.
A team of researchers led by Chen and others at the USC estimated the annual physical and cognitive health of 2,239 U.S. women between the ages of 74 and 92 from 2008 to 2018. (Chen and her colleagues focused on women because they are disproportionately affected by nervous system degeneration. Diseases such as Alzheimer’s disease that can lead to dementia). These women were geographically dispersed across the country, and all were dementia-free for at least 2008–2012. The researchers compared these estimates with the annual average concentrations of outdoor air pollutants in 1998 and 2012 to determine where air quality was healthier. levels. The research focused on measuring particulate matter and nitrogen dioxide – two very common pollutants from traffic exhaust.
During these 10 years, 398 women were diagnosed with dementia. But the researchers found that in places with higher air quality, a lower incidence of dementia diagnoses was observed among the women in the study. Although the reduction in risk varies with other factors, Chen explained that reducing air pollution exposure to about 15 percent below the current EPA standard threshold resulted in a 20 percent reduction in dementia risk.
In addition, the association between lower dementia risk and better air quality did not differ significantly by age, education, geography, or cardiovascular risk factors, suggesting that air pollution actually plays a larger role in dementia than previously thought.
The research is far from complete. The findings are likely to extend to older men, but we can’t be sure yet without actual data to confirm it. In addition, some women may have been exposed to much different levels of air pollution in their daily lives than the general air quality in their environment suggests. Other factors, such as green areas, may have affected air quality at the local level.
But there is little reason to doubt the general knowledge: human health is inseparable from environmental health.