The Journal of the American Medical Association (JAMA) today published the findings of a study directed by Mount Sinai School of Medicine Researchers and funded by the National Institute of Health (NIH). The findings indicate a significant independent association between exposure to long term air pollution and the acceleration of atherosclerosis and vascular inflammation in an animal model. For the first time researchers were able to substantiate the findings by recreating real-world exposure to air pollution in concentrations and size molecules strongly linked with cardiovascular disease.

“The findings validate breathing polluted air for an extended period of time puts you at substantial risk for heart disease, and the publication in JAMA certainly adds to the body of evidence,” said Dr. Sanjay Rajagopalan, MD FACC, Associate Professor of Medicine and Radiology, Director Clinical Cardiovascular MRI and CT Program at the Zena and Michael A. Wiener Cardiovascular Institute at the Mount Sinai School of Medicine and lead author of this study. “It has tremendous ramifications for public health and health policy for those of us living in cities.”

Real-world study validates findings
Other published studies on this topic use data collected from time-series analysis of human participants or in vitro studies where cells were exposed to non-physiologic and sometimes high concentrations of particulate matter. However, air pollution particles most strongly linked with cardiovascular disease are 2.5µm (PM2.5) and smaller and primarily derived from stationary and traffic-related combustion sources.

To better reflect human, real-world exposure, Mount Sinai School of Medicine Researchers used mice and airborne particulate matter with diminishing size down to .5µm to demonstrate an incremental capacity to penetrate to the most distal airway units and potentially the systemic circulation.

The Study
Mount Sinai School of Medicine Researchers tested the hypothesis that subchronic exposure to environmentally relevant particulate matter, even at low concentrations, causes atherosclerosis and alters vasomotor tone in a susceptible disease model.

Between July 21, 2004 and January 12, 2005, 28 mice were fed normal chow or high-fat chow and exposed to concentrated ambient particles of less than 2.5µm or filtered air for 6 hours per day, 5 days per week for a total of 6 months. To test the hypothesis, researchers looked for composite atherosclerotic plaque in the thoracic and abdominal aorta and vasomotor tone changes in the mice.

They concluded that in a mouse model, long-term exposure to low concentration of PM(2.5) altered vasomotor tone, induced vascular inflammation, and potentiated atherosclerosis.

You can read the full study in the December 21, 2005 issue of JAMA.