People Living in Areas with More Outdoor Pollution More Likely to Develop Heart Disease

A new 10-year epidemiological study of over 6,000 people from six U.S. states reveals that air pollution, even below regulatory standard levels, can hasten the progression of atherosclerosis or the hardening of arteries, which can lead to heart attack.

It has been previously known that long exposures to particulate matter can lead to heart disease. However, the biological process behind this connection has not yet been truly understood. Now, the new study, published in the journal The Lancet, offers direct evidence how exposure to particulate matter leads to disease in the cardiovascular system.

"The study provides important new information on how pollution affects the main biological process that leads to heart disease," said Dr. Joel Kaufman, a University of Washington professor of environmental and occupational health sciences, and also a UW professor of epidemiology, and of medicine, in a statement.

For the study, the researchers deployed air pollution monitors in more than 1,500 locations within six different metro areas. They also developed and applied computational models including local information on land use, roadway and traffic volumes, weather conditions, and local sources of air pollution to accurately generate pollution concentrations at each person's home.

Meanwhile, researchers measured the coronary artery calcium of 6,795 participants aged 45-84 years enrolled in the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air) using CT-scan. Most of the participants received CT-scans repeatedly between 2002 and 2005, for a subset of participants between 2005 and 2007, and for half of all participants between 2010 and 2012.

Researchers found out that for every 5 µg/m3 higher concentration of PM2.5, or 35 parts per billion higher concentrations of oxides of nitrogen, participants had a 4 Agatston units/year faster rate of progression of coronary artery calcium scores. This basically means that people living areas with high particulate matter and traffic-related pollutant gas called oxides of nitrogen experience 20 percent acceleration in the rate of calcium deposits in their heart arteries.

Their findings support the global efforts of pollution reduction in prevention of cardiovascular diseases.