Research on how air quality affects cognitive functions by the Keck School of Medicine of USC, has shown that exposure to air pollution later in life is connected to a higher risk of developing dementia, but until now it has been unknown how improving air quality would impact brain health.
“Our study is important because it is one of the first to show that reducing air pollution over time may benefit the brain health of older women by decreasing their likelihood of developing dementia,” said Xinhui Wang, PhD, lead author and assistant professor of research neurology at the Keck School of Medicine of USC. “The takeaway message is that reducing air pollution exposure can promote healthier brain aging.”
The link between air quality and brain health
Using data from the National Institutes of Health-funded Women’s Health Initiative Memory Study-Epidemiology of Cognitive Health Outcomes (WHIMS-ECHO), researchers analyzed the link between reductions in air pollution and the development of dementia among women aged 74 to 92.
The women, who did not have dementia at the beginning of the study, were given annual cognitive function tests from 2008 to 2018 to determine whether they developed dementia. Using participants’ home addresses, the study group created mathematical models to estimate air pollution levels at these locations over time.
Among women living in locations with the greatest reductions in two types of air pollutants — fine particulate matter (PM2.5) and nitrogen dioxide (NO2), a traffic-related pollutant — the risk of dementia decreased by 14% and 26% respectively. The benefit from lower air pollution was consistent despite differences among study participants in age, geographic area, socioeconomic background, cardiovascular risk factors and Apolipoprotein E genotype.