Women's Health

Smoggy Air Fogs the Brain

Women who spend most of their life breathing air pollution are more likely to have a decline in mental functioning as they age, a new study says.

Photo of smoggy cityscape

Researchers looking at data collected from the U.S. Environmental Protection Agency (EPA) and the U.S. Nurses' Health Study found that both fine and coarse particulate matter air pollution led to mental decline in women.

According to lead author Jennifer Weuve, Sc.D., at the Rush Institute for Healthy Aging in Chicago, the researchers also noted that the higher the level of particulate matter, the greater the impact on the women's cognitive scores.

Air particles

Particulate air pollution - particles of solid or liquid matter suspended in the air - is made up of acids such as nitrates and sulfates, organic chemicals, metals, and soil or dust, according to the EPA.

Fine particulate matter pollution in the U.S. is most often caused by combustion from cars, diesel engines, and industry. Sources of larger particles include roads, construction, mining, burning, and farming.

Generally, scientists believe that the smaller the particle, the deeper it can go into the body. Smaller particles travel farther into the lungs and can enter the bloodstream.

Long-term exposure

For the study, which was published in the Archives of Internal Medicine, the researchers examined data on more than 19,000 women ages 70 to 81. They calculated the participants' exposure to air pollution over a seven- to 14-year period. The women took a test over the phone to measure mental abilities such as memory and thinking skills. The tests were repeated two and four years later.

Every 10-unit increase in air pollution the women were exposed to aged them mentally by the equivalent of about two years.

On a population scale, the impact is tremendous, Dr. Weuve says. If millions of women are slightly older mentally than they would be otherwise, that has a huge impact on quality of life, on their families, and on the societal costs of taking care of them.

"Unlike other factors that may be involved with dementia, air pollution is unique because we can intervene as a society at large, through policy, regulation, and technology," Dr. Weuve says.

Pollution and health

Previous studies have found that air pollution is linked to cardiovascular disease. And cardiovascular disease has been shown to speed up mental decline. So the link between air pollution and women's mental decline might be explained by pollution's effect on cardiovascular health.

Dr. Weuve also says it's possible that the particles are reaching the brain itself. This could cause inflammation in the brain and potentially trigger the microscopic changes that mark the onset of Alzheimer's disease.

Always talk with your health care provider to find out more information.

Online Resources

(Our Organization is not responsible for the content of Internet sites.)

American Academy of Family Physicians - Air Pollution

CDC - Air Pollution & Respiratory Health

Lawrence Berkeley National Laboratory - How can air pollution hurt my health?

April 2012

What Are You Breathing?

When you breathe in gases like carbon monoxide or nitrogen dioxide, they are absorbed by the cells that line the airways to the lungs. Once absorbed, the gases pass into the bloodstream and travel to your internal organs, where they can cause damage. If the gases are not entirely absorbed by the airways, they can reach the lungs, where they can do further damage.

Large particles in the air are filtered out by cilia, the small hairs that line your respiratory tract. Smaller particles, however, reach your airways and lungs. Particles of all sizes also land on crops and in water that are eventually consumed by humans and by animals that humans eat.

The effects of air pollution differ from person to person. A healthy adult who is exposed to these pollutants for a short time or at low dose may not develop long-term problems. For a person with a heart or respiratory condition, however, even a small dose or a short exposure can make symptoms worse. Longer exposure or a higher dose can lead to serious illness and, in some cases, death. Children and the elderly are more susceptible to air pollution than other individuals and suffer the effects at lower pollution levels.

Always talk with your health care provider to find out more information.

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