A major new study led by a University of Washington School of Public Health professor found that people living in areas with more outdoor pollution — even at lower levels common in the U.S. — accumulate deposits in their coronary arteries faster than people living in less polluted areas.
[Photo: Dr. Joel Kaufman]
The study, involving more than 6,000 people in six states over 10 years, was published online in The Lancet on May 24.
The Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air) shows that air pollution — even at levels below regulatory standards — accelerates the progression of atherosclerosis, the hardening of the arteries, which causes heart attacks. Researchers measured calcium deposits in the heart’s arteries repeatedly using CT scans and assessed each person’s exposure to pollution based on home address.
“On average we found a 20 percent acceleration in the rate of calcium deposits,” lead author Dr. Joel Kaufman, professor of environmental and occupational health sciences, epidemiology, and internal medicine, told The Seattle Times. “I would say the results are a little more clear-cut and dramatic than I expected when I started this.”
The researchers calculated each participant’s exposure to ambient fine particulate matter (PM2.5), oxides of nitrogen, and black carbon or soot. The research team collected thousands of air pollution measurements in the study participants’ communities and at their homes. Results were strongest for fine particulate matter (PM2.5, particulate matter that is less than 2.5 microns in diameter) and the traffic-related pollutant gases called oxides of nitrogen (NOx).
“The effects were seen even in the U.S. where efforts to reduce exposure have been notably successful compared with many other parts of the world,” Dr. Kaufman said. Exposures were low when compared to U.S. ambient air quality standards, which permit an annual average PM2.5 concentration of 12 µg/m3. The participants in this MESA-Air study experienced concentrations between 9.2 and 22.6 µg/m3.
The MESA Air study was funded in 2004 by the U.S. Environmental Protection Agency, and involved researchers at a number of institutions, and characterized air pollutant exposures experienced by people in the National Heart, Lung, and Blood Institute’s Multi-Ethnic Study of Atherosclerosis (MESA). Other funding for this study came from the National Heart, Lung, and Blood Institute and the National Institute of Environmental Health Sciences. The participants lived in six major cities across the United States, and 39 percent were White, 12 percent were Chinese, 27 percent were Black, and 22 percent Hispanic. The clinics were in: Baltimore, Chicago, Los Angeles, New York City, St. Paul and Winston-Salem.