The tiny particulate pollution from cars, power plants and factories does more than clog your lungs. It leads to development of heart disease, according to a BYU researcher.

The findings were published Monday in Circulation: Journal of the American Heart Association, in the rapid-access issue.

"It's very different from what we thought previously," said professor and epidemiologist Arden Pope of Brigham Young University, who led the study. While exposure clearly impacts the lungs, "long-term, chronic exposure to air pollution seems to manifest more in cardiovascular disease than it does in respiratory disease."

The link between air pollution and increased deaths has been shown in research by Pope and others. His most recent study, however, shows the biological mechanism by which long-term exposure to tiny-particle pollution can actually lead to ischemic heart disease, which causes heart attacks, as well as irregular heart rhythms, heart failure and cardiac arrest.

The key is inflammation, he said. While strong bouts of pollution can make breathing hard and increase respiratory problems, they also provoke low-grade pulmonary inflammation, accelerating development of atherosclerosis — a leading cause of heart disease — and altering heart function.

The result of the research "extends to levels we're exposed to along the Wasatch Front. The problem is that in most cases, for most people, you won't actually feel the effects in an acute way. It's the accumulation of long-term exposure and the low-grade inflammation that results in somewhat more rapid progression of atherosclerosis. None of us who are healthy are likely to feel impacts, which are longer-term."

When pollution hangs around for a long time, the irregular heartbeats and other effects on cardiac function can be felt.

The tiny particulates Pope's talking about are in the same size range as particles from environmental tobacco smoke, which research shows makes the same changes in lung and heart function, he said. The risk depends on how much of each — either environmental tobacco smoke or air pollution — to which one is exposed. Active cigarette smoking poses greater risks than even pollution, and this study indicates how smoking may lead to heart disease.

Utah is "an interesting place in that, unlike many places, where pollution is generated more regionally and cities add to it, along the Wasatch Front, most of our pollution is our own. Our air is either very clean when weather conditions are such they are dispersing the pollution we generate, or we are relatively dirty during those times when we have stagnant air. Then we can have relatively high pollution. On average, we are sort of a moderately polluted area. But our air quality has been improving."

While Pope said he didn't want to overstate the importance of the the research, it adds "biological plausibility" that air pollution really is a risk factor for heart disease.

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The pollution linked to cardiovascular deaths was particulate matter smaller than 2.5 microns, also called PM2.5. It's created by combustion, usually by automobiles, manufacturing and coal-fired power plants.

The Environmental Protection Agency states the annual average level of PM2.5 particles in the air shouldn't exceed 15 micrograms per cubic meter. Pope found that each 10 micrograms-per-cubic-meter increase in fine-particulate air pollution raises by 18 percent risk of death from ischemic heart disease and by 13 percent risk of death from heart function changes.

Other co-authors are Dr. John J. Godleski of Harvard Medical School; Richard Burnett and Daniel Krewski of the University of Ottawa; George Thurston and Kazuhiko Ito of the New York University School of Medicine; and Michael Thun and Eugenia Calle of the American Cancer Society. The research was supported by a grant from the national Institute of Environmental Health Sciences and a Health Effects Institute contract.


E-MAIL: lois@desnews.com

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