Long-Term Exposure to Air Pollution Contributes to Very Early Stages of Artery Disease
The greater the fine particle air pollution around a person’s home, the thicker the walls of their carotid arteries, the large blood vessels in the neck that carry blood to the brain, according to a University of Southern California study.
Researchers reviewed data from two clinical trials of 800 healthy people with elevated cholesterol, ages 40 and older, who lived in the Los Angeles, California area. The clinical trials used ultrasound to collect baseline measurements of the thickness of the inner lining of participants’ carotid arteries. This provides a measure of the level of atherosclerosis in the early stages, before symptoms are evident. Atherosclerosis, or hardening of the arteries, decreases the flow of oxygen-rich blood, increasing the risk for heart pain, heart attacks, and stroke.
Researchers used ambient monitors to assign an annual mean PM2.5 level to the subjects’ home zip codes. After adjusting for age, smoking, and physiological factors, they found that increased artery thickness was associated with higher fine particle exposures. The association was strongest in women over 60.
“These results represent the first evidence of an association between atherosclerosis and ambient air pollution,” concluded the researchers. “The findings indicate a biologically plausible link between the observed acute effects of ambient air pollution on systemic inflammation and the long-term consequences of sustained vascular inflammation leading to increased atherosclerosis and, ultimately, cardiovascular death.”
Künzli N, Jerrett M, Mack WJ, Beckerman B, LaBree L, Gilliland F, Thomas D, Peters J, Hodis HN. Ambient air pollution and atherosclerosis in Los Angeles. Env Health Persp 2005; 113:201-20
The National Institute of Environmental Health Sciences [ehp.niehs.nih.gov] offers the full article online.
