Debbie Nicholson

Seniors residing in areas with high air pollution leads to impaired cognitive function

This new analysis conducted by Dr. Jennifer Allshire, PhD, a sociologist and social demographer at the USC Davis School of Gerontology/Ethel Percy Andrus Gerontology Center; her findings are based on information from the U.S. Environmental Protection Agency and the Health and Retirement Study.

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"As a result of age-related declines in health and functioning, older adults are particularly vulnerable to the hazards of exposure to unhealthy air," stated Dr. Allshire in public release. According to Allshire air pollution has been linked to cardiovascular and respiratory problems and even premature death among seniors. Air pollution is a significant risk factor for multiple health conditions including respiratory infections, heart disease, and lung cancer, according to the WHO. The health effects caused by air pollution may include difficulty in breathing, wheezing, coughing and aggravation of existing respiratory and cardiac conditions. She further notes that there is emerging evidence that air pollution may have adverse effects on brain health and functioning.

This year a nationwide study followed almost 20,000 women for a period of ten years and found breathing in high levels of air pollution greatly accelerates declines in memory and attention span. Ohio State University researchers in 2011 examined the effects of pollution particles on the brain of mice and found exposure to pollutants affected the hippocampus of the brain.

This analysis is the first of its kind to show how cognitive function in a national sample of older men and women.

The study’s sample had included 14,793 Caucasian, African American and Hispanic men and women aged 50 years and older and who had participated in the 2004 Health and Retirement Study (a longitudinal panel study that surveys a representative sample of more than 26,000 Americans over the age of 50 every two years). Individual information was associated to data on 2004 annual average levels of fine air particulate matter from the Environmental Protection Agency's Air Quality System monitors across the country. Participant’s cognitive function was calculated on a scale of 1 to 35 and had consisted of tests that evaluated word recall, knowledge, language, and orientation.

Dr. Allshire’s results revealed that participants that were residing in areas with high air pollution had poor scores on the cognitive function tests. After taking into account several factors that had included age race/ethnicity, education, smoking behavior, and respiratory and cardiovascular conditions, the link still remained the same.

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. This means that by comparison the effect was nearly equal to that of aging by three years, among all participants and a one-year increase in age was associated with a drop 0.13 in cognitive function score.

This study suggests that fine air particle matter (2.5 micrometers in diameter and smaller) which are believed to be significantly small that if they are inhaled they can deposit deep into the lung and possibly the brain therefore making them an important environmental risk factor for cognitive function decline.

This new research was presented at the Gerontological Society of America's (GSA) 65th Annual Scientific Meeting, held in San Diego, California, Wednesday, 11/14 to Sunday, 11/18.

Earlier this year Rush University Medical Center conducted a large prospective study and found chronic exposure to air particle pollution could accelerate cognitive decline in older adults.

Their study included 19,409 American women aged 70 to 81 years from the Nurses' Health Study Cognitive Cohort. The study examined long term exposure to particle matter (PM) air pollution both course (2.5-10 μm in diameter) and fine (<2.5 μm in diameter) in association to cognitive decline.

Their results showed exposure to PM 2.2 – 10 and PM 2.5 levels in which are the levels typically experienced by many Americans is linked with significant and worsening cognitive decline in older women.

The World Health Organization states that 2.4 million people die each year from causes directly attributable to air pollution, with 1.5 million of these deaths attributable to indoor air pollution.

More information on the effects of air pollution can be found at the EPA website.