Indoor and outdoor pollutants can rapidly harm the heart in ways different than outdoor air pollution alone, according to a new study presented at the American Heart Association’s Scientific Sessions. The Cardiovascular Sub-study of the Detroit Exposure and Aerosol Research Study (DEARS) is the first study to show that two different aspects of exposure - community wide and personal - have differing adverse health outcomes on the heart and blood vessels.
Researchers examined short-term personal exposure by fitting participants with pollution-monitoring vests. They found that total exposure was influenced by sources in open air as well as enclosed spaces and that exposure was linked to an increase in systolic blood pressure and blood vessel constriction. These increases could play a role in promoting sudden heart attacks, strokes and heart failure.
Community exposure, which measures pollution in a broader area from fixed monitoring stations and is not as effective in determining personal exposure, was only associated with impaired blood vessel functioning.
The study included 65 men and women from diverse ethnic backgrounds. They ranged from 19 to 80 years old and 80 percent were women. All the participants were nonsmokers living in nonsmoking households. For three years, 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, 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 in micro-environments such as their homes, restaurants, at work, or near traffic.
Researchers found that an increase in personal exposure to pollution (10 micrograms per cubic meter) narrowed blood vessel diameter in arms (a potential condition that could lead to heart and vascular events) by 18 percent two days after exposure.
Researchers also found that although the participants were nonsmokers living in nonsmoking homes and told to avoid tobacco smoke during the study, approximately 30 percent were still exposed to secondhand smoke. “At the community level, a 10 microgram per cubic meter increase in pollution leads to a 1 percent increased chance of dying the next day,” said Robert D. Brook, M.D., the study’s lead investigator and associate professor of Medicine in the Division of Cardiovascular Medicine at the University of Michigan in Ann Arbor.” Within a city of 1 to 5 million that increase would lead to about one death per day.”
Globally, air pollution is the 13th leading cause of death. Air pollution blankets cities throughout the world. The cumulative yearly exposure contributes to tens of thousands of deaths in the United States and an estimated 800,000 deaths throughout the world, Brook said. Researchers conclude that the sources and characteristics of air pollution may be important determinants of the health responses.