Bad Air Causes Decrease in Cognitive Functions

A new finding based on data from the U.S Environmental Protection Agency and the Health and Retirement Study has a cautionary message for older adults.

According to the study, older people living in areas of  high  air pollution may suffer from decreased cognitive functions. The analysis was done by Jennifer Ailshire, PhD, a National Institute on Aging postdoctoral fellow in the Center for Biodemography and Population Health and the Andrus Gerontology Center at the University of Southern California.

"As a result of age-related declines in health and functioning, older adults are particularly vulnerable to the hazards of exposure to unhealthy air," Ailshire said. "Air pollution has been linked to increased cardiovascular and respiratory problems, and even premature death, in older populations, and there is emerging evidence that exposure to particulate air pollution may have adverse effects on brain health and functioning as well."

Highlighting the exposure to air pollution and its influence on cognitive functions in a national sample of older men and women was the first study of its kind.

The study is a first of its kind done on a national sample of older men and women. It states that fine air particles 2.5 micrometers in diameter and smaller, have the capacity of settling deep inside the lungs and possibly the brain, when inhaled. And this is an important environmental risk factor for reduced cognitive function.

The study had 14,793 white, black, and Hispanic men and women aged 50 and older who participated in the 2004 Health and Retirement Study. Individual data were linked with data on 2004 annual average levels of fine air particulate matter from the Environmental Protection Agency's Air Quality System monitors across the country. 

In order to measure the cognitive functions they were given tests such as word recall, knowledge, language, and orientation. Their performance was rated on a scale of 1 to 35.

Ailshire discovered that those living in areas with high levels of fine air particulate matter scored low on the cognitive function tests.

For the study, the researchers took several factors such as age, race/ethnicity, education, smoking behavior, and respiratory and cardiovascular conditions into account.

The report states that fine air particulate matter exposures ranged from 4.1 to 20.7 micrograms per cubic meter, and every ten point increase was associated with a 0.36 point drop in cognitive function score. In comparison, this effect was roughly equal to that of aging three years; among all study subjects, a one-year increase in age was associated with a drop 0.13 in cognitive function score.

The new research was presented in San Diego at The Gerontological Society of America's (GSA) 65th Annual Scientific Meeting.