Air pollution may not only be hazardous to your lungs, it may trigger and accelerate the narrowing of your carotid arteries, according to a new study. In fact, researchers found an association between long-term air pollution exposure and the early stages of atherosclerosis (hardening of the arteries).
Even worse, air pollution may contribute to cardiovascular problems at a very early stage of the disease, similar to smoking, and enhances atherosclerosis, which is the underlying disease process of cardiovascular diseases, one scientist said.
Researchers reviewed data from two clinical trials on some 800 people over 39 who live in the metro Los Angeles area, including baseline measurements of the thickness of the inner lining of the patients' neck arteries (carotid artery intima-media thickness or CIMT). CIMT is measured by ultrasound and used to determine the level of subclinical atherosclerosis.
Researchers then assigned a PM2.5 particle level -- pollutants emitted from burning fossil fuels or processing metals with a diameter of no more than 2.5 micrometers -- to the study subjects' home ZIP codes. These pollutants are tiny enough to be inhaled into the smallest airways.
Air pollution causes the body to produce oxidants (unstable molecules) that cause inflammatory reactions in both the respiratory tract and blood vessels, triggering artery damage. Some air particles find their way into the blood or even the brain, according to scientists.
The association between air pollution and CIMT was especially strong among these groups:
- People over age 60
- Women (especially those over age 60)
- Those who take cholesterol-lowering medication
Science Daily November 15, 2004