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Polluted Air Could Be Harmful to the Senior Brain

A new study shows that exposure to high levels of air pollution can cause decreased mental function in older adults.

Polluted air-- by Megan McCrea

The Gist

Nobody would be surprised to learn that the brown cloud of smog hanging over a city is harmful to the respiratory health of its citizenry. Air pollution, however, may be more harmful to human health than previously thought, as a new study of senior-age citizens shows that this type of pollution might have negative effects on the human brain.

One major contributor to air pollution is fine particulate matter (FPM). Composed of extremely small particles and liquid droplets, FPM forms when gases from automobiles and gases from industrial sources react in the air. FPM can be found in smoke and haze.

Over the years, studies have shown that exposure to high levels of FPM can cause respiratory issues like coughing, shortness of breath, asthma, and bronchitis. Exposure to air pollution has also been linked to heart problems, and even premature death.

Although much attention has been paid to air pollution’s effects on the body, there has been less research into its effects on the brain.

New research, presented today at the Gerontological Society of America’s 65th Annual Scientific Meeting, explores the effects of air pollution on the cognitive function of older adults. Through extensive surveys, the researchers found that seniors living in areas with more air pollution scored far lower on cognitive tests than did participants living in less polluted areas.

The Expert Take

Study author Dr. Jennifer Ailshire, a medical sociologist and gerontologist at the University of Southern California, explained the impetus behind the inquiry.

“There has been no study, to my knowledge, that has examined the link between fine particulate matter air pollution and cognitive function in the older U.S. population,” she explained.

While there have previously been studies that assessed the link between pollution and brain function, all of those studies had focused on a very distinct sample—older German women or white veterans, for instance. On the other hand, Ailshire explained, this study “used a national sample of older [men] and women that is socioeconomically, racially, and ethnically diverse.”

Thus, these findings are more likely to be applicable to the population at large.

Ailshire and her colleagues theorize that older adults may be more vulnerable to the effects of pollution than other demographic groups.

“Individuals who have preexisting cardiovascular and respiratory conditions are more susceptible to the adverse health effects of air pollution,” Ailshire explained. Since older adults are more likely to suffer from these conditions, they are more vulnerable to the adverse effects of pollution.

Surprisingly enough, there is a silver lining.

“There are a lot of factors that contribute to poor health and aging-related declines in health and functioning,” explained Ailshire. While many of these factors cannot be controlled—think genes and early life conditions—air pollution is something that we can change. “This is a health threat that we can do something about,” said Ailshire.

That is, by taking action to decrease air pollution, we can make a real difference in seniors’ lives. “It’s important to [remember] that we have decreased pollution levels in this country,” she said, citing Los Angeles as an example.

But what can seniors do, on an individual level, to maintain their cognitive function?

Healthline spoke to Dr. Charles Cefalu, chief of geriatric medicine at LSU Health Science Center, to find out what seniors can do to decrease their risk.

He recommended that seniors use proven strategies to maintain good cognition. “Exercise has been shown to prevent the development of dementia,” he noted. Thus, he recommended exercising regularly in order to keep the neurons firing.

If you’re ready for a big change, he said, you could even consider moving to an area with lower levels of pollution.

Source and Method

This research is being presented today at the Gerontological Society of America’s (GSA) 65th Annual Scientific Meeting. The GSA is one of the nation’s leading organizations devoted to the study of aging.

During the study, the researchers examined data from the 2004 Health and Retirement Study, a nationwide survey of American adults over 50. The sample group included 14,793 black, white, and Hispanic men and women. The study assessed the people’s thinking and reasoning abilities by testing their working memory, language ability, knowledge, and orientation.

The researchers also noted the level of pollution in the area where each person lived, measured by micrograms per cubic meter of fine particulate matter (FPM). The researchers then analyzed the data, adjusting for potentially complicating factors such as age, gender, race, education level, marital status, smoking status, and general overall health. The researchers used a regression model to assess how fine particulate matter pollution affected participants’ cognitive abilities.

The study found that the adults living in more polluted areas scored lower on cognitive tests their counterparts, even after adjusting for demographic, health, and lifestyle factors.

The Takeaway

The study should raise concern among all people, particularly older adults living in large urban areas, which tend to experience the most pollution.

Ways to minimize your exposure to air pollution include:

  • move to a less polluted area
  • check the air quality index (AQI) for your area, on, to find out about your local air quality and forecasts
  • on days when the air quality is poor, avoid prolonged physical exertion outdoors
  • on days when the air quality is poor, avoid heavy exertion outdoors

What’s more, as a society, we might consider ways to decrease fine particulate air matter. For instance, we could think twice before expanding a freeway that runs directly through a community. We could also work on building better public transit options, so people could become less reliant on cars for everyday transportation needs.

Other Research

Several studies have examined the effects of air pollution on the brain and on people’s cognitive abilities.

A 2012 study, published in the Journal of Alzheimer’s Disease, followed two groups of urban children. One group was exposed to a great deal of air pollution, while the other was exposed to minimal air pollution. Those exposed to greater levels of pollution had increased brain inflammation.

A German study, published in 2009 in Environmental Research, examined a group of elderly women living in areas with different levels of traffic-related pollution. Those women who lived in polluted areas performed worse on cognitive tests than those women living in other areas.

In a 2009 study, published in Neurotoxicology, epidemiologists from the UNC School of Public Health analyzed national data on American adults exposed to FPM and ozone pollution. While they did initially find a decrease in cognitive ability correlated to air pollution, that difference disappeared once they adjusted for sociodemographic factors.

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Tags: Global Health , Latest Studies & Research , Public Health & Policy

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The Healthline Editorial team writes about the latest health news, policy, and research.