Indoor and outdoor pollutants can adversely affect the heart in ways different from outdoor air pollution alone, according to a new cardiovascular study conducted by researchers at the University of Michigan, in collaboration with an exposure study conducted by RTI International.

The Cardiovascular Sub-Study of the Detroit Exposure and Aerosol Research Study (DEARS) has shown for the first time that two different aspects of air pollutant exposure-community wide and personal level-have differing adverse health outcomes on the heart and blood vessels. The Cardiovascular Sub-Study was lead by the University of Michigan, while the DEARS study was lead by RTI.

The cardiovascular study results were presented at the American Heart Association’s Scientific Sessions 2008.

RTI researchers examined short-term personal exposure by fitting participants with custom-designed miniature samplers and pollution-monitoring vests.

The University of Michigan researchers found that total personal exposures in the DEARS were influenced by both ambient (open air) and non-ambient (within enclosed spaces) sources and were linked to an increase in systolic blood pressure and blood vessel constriction. Such changes could play a role in promoting sudden heart attacks, strokes and heart failure.

On the other hand, the DEARS central site community exposures, which measure pollution in a broader area from a fixed monitoring station but cannot determine as precisely a specific individual’s personal exposure, were associated with impaired blood vessel functioning alone.

'This study goes beyond corroborating that air pollution can adversely affect blood pressure and blood vessel health,' said Robert D. Brook, M.D., the cardiovascular study’s lead investigator and associate professor of Medicine in the Division of Cardiovascular Medicine at the University of Michigan in Ann Arbor. 'We saw health effects of personal exposure that occurred in individuals on top of those due to background (central site) pollution.'

Sixty-five men and women from diverse ethnic backgrounds participated in the study. They ranged in age from 19 to 80 years, and 80 percent were women. All were nonsmokers living in nonsmoking households in three different areas of Detroit.

For three years, RTI researchers examined the personal and community exposure to air pollutants for five consecutive days in the summer and five consecutive days in the winter. At the end of each research day, University of Michigan field investigators came to each participant's home to measure the effects of pollutants on blood pressure and blood vessel function.

The vest monitors gave a continuous record of what people were exposed to through 24-hour periods for five consecutive days. These personal monitors measured what the person might be exposed to walking in and out of small micro-environments such as a house or restaurant, or walking by a freeway, a bus stop or a workplace emitting high levels of pollutants.