Decreasing air pollution levels leads to fewer cases of dementia

LOS ANGELES, Calif. — Air pollution increases the risk of developing dementia, according to a new study. Luckily, researchers from USC add this effect is reversible. Their results found that decreasing exposure to air pollution later in life can lead to healthier brain aging.

“Our results shows that the benefits may be universal in older women, even those already at greater risk for dementia,” says Xinhui Wang, PhD, lead author and assistant professor of research neurology at the Keck School of Medicine in a university release.

Less traffic leads to less dementia

The research team collected data from the Women’s Health Initiative Memory Study-Epidemiology of Cognitive Health Outcomes (WHIMS-ECHO) to study the link between air pollution and dementia among women between the ages of 74 to 92.

Women without dementia at the start of the study took annual cognitive tests, looking for any signs of mental decline. Using each woman’s home address, the researchers created models to examine changes in air pollution levels from 2008 to 2018.

Results show that women living in areas with the greatest decline in two types of air pollution, fine particulate matter and traffic-related nitrogen dioxide, enjoyed a reduction in their likelihood of developing dementia.

More specifically, decreases in fine particulate matter risk had a link to a 14-percent reduced risk of dementia. Drops in traffic-related pollutant nitrogen dioxide also dropped the risk of dementia by 26 percent. These effects remained the same regardless of participants’ age, socioeconomic status, heart risk, apolipoprotein E genotype, and geographic location.

Improving air quality from less pollution correlated with good cognitive function and memory in the study participants. The findings suggest reducing pollution improves various brain areas.

Reducing air pollution has a financial benefit for families

Dementia is a devastating neurodegenerative disease that disproportionally targets women. It also incurs a costly burden to patients and affected families. Dementia is one of the most expensive chronic diseases in the United States. Annual costs ranging from $159 billion to $215 billion in 2010 and are expected to increase in the future.

“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,” concludes Diana Younan, PhD, a former senior research associate in the department of Population and Public Health Sciences and the study’s other lead author.

The study is published in the journal Proceedings of the National Academy of Sciences.