Research shows that dementia and air pollution could be linked

High levels or air pollution could contribute to approximately 21 percent of dementia cases. (Photo: Pixabay)

New research strengthens the previously reported link between air pollution and cognitive decline, after finding that exposure to fine particulate matter could significantly raise the risk of developing Alzheimer's disease and other forms of dementia.

The research found that exposure to high levels of particulate matter 2.5 (PM2.5) - tiny air pollution particles that are up to 2.5 micrometers in diameter - increased older women's risk of dementia by over 90 percent, compared with low PM2.5 exposure.
Senior study author Prof. Caleb Finch, of the Leonard Davis School of Gerontology at the University of Southern California (USC), and colleagues say that if their findings apply to the general population, then PM2.5 could account for around a fifth of dementia cases. The researchers recently reported their findings in the journal Translational Psychiatry.

PM2.5 are fine particles consisting of solids and liquid droplets that are emitted from sources involving combustion, such as power plants and motor vehicles. PM2.5 are 2.5 micrometers in diameter or smaller. To put their size into perspective, the diameter of a PM2.5 particle is around 30 times smaller than that of a human hair.

Because they are so small, PM2.5 are easily inhaled, which can pose numerous health issues. According to the United States Environmental Protection Agency (EPA), exposure to fine air particles can increase the risk of heart attacks, asthma, and reduced lung function, as well as premature death for individuals with heart or lung disease.

In recent years, studies have suggested that exposure to such pollution may also raise the risk of dementia. Prof. Finch and team decided to investigate this association further in their new study.

Alzheimer's risk increased by 92 percent with high PM2.5 exposure

The study included the data of 3,647 women from 48 U.S. states who were part of the Women's Health Initiative Memory Study (WHIMS). All women were aged between 65 and 79 and were free of dementia at the time of study enrollment. As part of the WHIMS, participants' cognitive function was assessed annually. Using data from the EPA, the team estimated the women's daily PM2.5 exposure at their place of residence.

Compared with women who lived in areas exposed to low PM2.5 levels, those who resided in areas with high PM2.5 levels - defined as levels that exceeded the EPA's permissible limit in 2012 (35 micrograms per cubic meter of air) - were found to be at an 81 percent greater risk of global cognitive decline and have a 92 percent increased risk of developing Alzheimer's disease and other dementias.

The results remained after accounting for numerous confounding factors, including race and ethnicity, socioeconomic status, lifestyle, and the presence of other medical conditions. The researchers estimated that if their findings ring true among the general population, then exposure to high PM2.5 levels could contribute to approximately 21 percent of dementia cases.

The authors of the study conclude by saying that:

"The association between PM2.5 exposure and increased dementia risk suggests that the global burden of disease attributable to PM2.5 pollution has been underestimated, especially in regions with large populations exposed to high ambient PM2.5."

Author: Honor Whiteman – 02/2017

With kind permission to publish from MNT

To read the complete article, please go to: Medical News Today

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