Dementia Risk Increased By Long-Term Exposure To Air Pollution

(CTN News) – Those exposed to particulate air pollution for a prolonged period of time are at risk of dementia, according to a study by the University of Michigan School of Public Health.

According to a study published in the journal JAMA Internal Medicine, Boya Zhang, a researcher at the University of Michigan, and colleagues found that exposure to fine particulate matter (PM2.5) air pollution was most strongly associated with incident dementia when the pollution came from agriculture and wildfires.

Dementia affects approximately 10% of the U.S. population over the age of 70. There is recent evidence suggesting that air pollution is a risk factor for dementia.

However, the details of this link, such as whether there are specific sources of air pollution that cause more dementia than others, are not clear at this time.

As one of the largest cohort studies of its kind in the United States, the Health and Retirement Study is a population-based study.

To conduct this study, data was collected from approximately 27,857 participants aged 50 or older who participated in the Health and Retirement Study between 1998 and 2016.

Researchers monitored the total exposure to PM2.5 at participants’ residences over a period of 10 years as well as exposure to nine different sources of PM2.5 on a monthly basis.

In addition to agricultural practices, road traffic, non-road traffic, coal combustion for energy production, other energy production, coal combustion for industry, other industry, wildfires, and windblown dust, PM2.5 exposure was associated with a number of factors.

The overall median 10-year total PM2.5 exposure ranged from 9.5 to 13.2 μg/m3. There was a difference between the Midwest and the West in terms of PM2.5 exposure from different sources.

As a result of the follow-up period, 4105 (15%) individuals in the cohort developed dementia. There was an 8% higher risk of incident dementia associated with exposure to higher levels of PM2.5 over the course of the 10-year follow-up period.

Researchers examined the different sources of air pollution and found that all were associated with incident dementia, except dust, which was strongly associated with pollution from agriculture, traffic, coal combustion, and wildfires.

In spite of controlling for PM2.5 from all other sources and co-pollutants, PM2.5 from agriculture and wildfires significantly increased risk by 13% and 5%, respectively.

According to our estimation, nearly 188,000 new cases of dementia were attributable to total PM2.5 exposure in the U.S., indicating that reducing PM2.5 through actions such as regulations, technological advances, or the use of personal air purifiers may promote healthy cognitive aging,” write the authors.

Moreover, our findings suggest that intervening on key emission sources might be beneficial, though causality cannot be determined, and more research is needed to support these conclusions.”

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