Study shows how air pollution fosters heart disease

http://www.eurekalert.org/pub_releases/2016-05/uowh-ssh052316.php

Public Release: 24-May-2016
Study shows how air pollution fosters heart disease
10-year project revealed air pollutants accelerate plaque build-up in arteries to the heart
University of Washington Health Sciences/UW Medicine

Long-term exposure to air pollution has been linked to an increased risk of heart disease, but the biological process has not been understood. A major, decade-long study of thousands of Americans found that people living in areas with more outdoor pollution -- even at lower levels common in the United States -- accumulate deposits in the arteries that supply the heart faster than do people living in less polluted areas.

•••••

Now, direct evidence from the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air), a 10-year epidemiological study of more than 6,000 people from six U.S. states, shows that air pollution -- even at levels below regulatory standards -- accelerates the progression of atherosclerosis. The condition, also called hardening of the arteries, can cause heart attacks. Researchers repeatedly measured calcium deposits in the heart's arteries by using CT scans. They also assessed each person's exposure to pollution based on home address.

•••••

Results were strongest for fine particulate matter and the traffic-related pollutant gases called oxides of nitrogen. The study found that for every 5 µg/m3 higher concentration of PM2.5, or 35 parts per billion higher concentration of oxides of nitrogen -- about the difference between more and less polluted areas of a U.S. metropolitan area -- individuals had a 4 Agatston units/year faster rate of progression of coronary artery calcium scores. This is about a 20 percent acceleration in the rate of these calcium deposits.

"The effects were seen even in the United States where efforts to reduce exposure have been notably successful compared with many other parts of the world," 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.

•••••