Air Quality Improvement Linked with Slower Cognitive Decline, Lower Dementia Risk

Air pollution comes with many health risks, including an increased risk of Alzheimer’s. A team at the University of Southern California wanted to see if the reverse was true: That improvements in air quality could actually lower the risk of dementia. It turns out that may be the case.


The USC researchers investigated the link between reductions in air pollution and the development of dementia in senior women. Over a ten-year period, they tracked air pollution levels where the participants lived and administered yearly cognitive tests. The findings, published in Proceedings of the National Academy of Sciences, show that the women who lived in areas with the largest reductions in key air pollutants were less apt to develop dementia over the study period. This provides further clues on how to combat cognitive decline.

Dr. Xinhui Wang, co-lead author and assistant professor of research neurology at the Keck School of Medicine at USC, says, “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. The takeaway message is that reducing air pollution exposure can promote healthier brain aging.”

To conduct the research, the team used data from the Women’s Health Initiative Memory Study-Epidemiology of Cognitive Health Outcomes, funded by the National Institutes of Health. Participants consisted of women between the ages of 74 and 92 who did not have dementia at the onset of the study period, which ran from 2008 through 2018.


The team found that women who lived in areas with the highest reduction in fine particulate matter and nitrogen dioxide saw a decreased dementia risk of 14% and 26%, respectively. These benefits were found across age groups, geographic areas, and socioecomomic backgrounds, as well as in those with health risks related to heart health and dementia. Additionally, air quality improvement was linked with overall cognitive and memory benefits.

The team says working to improve air quality across the board could help expand these benefits to others and provide further protections to public health.

Dr. Diana Younan, co-lead author and former senior research associate in the department of Population and Public Health Sciences, says, “Alzheimer’s disease and related dementias are immensely costly both to the healthcare system and to the families who struggle to take care of their older members. Our research suggests that tightening the air quality standards may help to prevent Alzheimer’s disease and related dementias in older women and, in turn, reduce its societal burden.”


If you’d like to read the whole study, click here.

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