Air Pollution Increases Lung Cancer Risk

Medically Reviewed by Charlotte E. Grayson Mathis, MD
From the WebMD Archives

March 5, 2002 -- The brown haze on the horizon is bad for your health -- very, very bad. Long-term exposure to air pollution is a serious risk factor for heart disease and lung cancer, says a new study.

In the study, researchers compared health data and death records on 500,000 Americans, all based on information collected by the American Cancer Society over a 16-year period, from 1982 to 1998. Participants represented a cross-section of cities across the country and Puerto Rico.

"This study is compelling because it involved hundreds of thousands of people in many cities across the U.S. who were followed for almost two decades," says researcher George Thurston, ScD, associate professor of environmental medicine at NYU School of Medicine, in a news release.

The team found "the strongest evidence to date that long-term exposure to fine particulate air pollution common to many metropolitan areas is an important risk factor for [death from heart disease]," writes C. Arden Pope, III, PhD, a researcher at Brigham Young University in Provo, Utah.

"Significant increases in lung cancer [deaths]" were also linked with air pollution, says Pope.

The study is published in this week's issue of Journal of the American Medical Association.

The researchers analyzed information from questionnaires in which people were asked about age, sex, race, weight, height, smoking history, education, marital status, diet, alcohol consumption, and occupational exposures to toxins. They also looked at cause-of-death information for deceased individuals in this group from 1984 to 1998.

After factoring in such known risk factors as cigarette smoking, bad diet, obesity, and occupational exposure to toxins, researchers found that air pollution significantly increased risk of death from lung cancer and heart disease.

"The increased risk of lung cancer and heart disease from air pollution was clearly far less than the risks associated with active cigarette smoking," says Pope. "However, we found that the risk of dying from lung cancer as well as heart disease in the most polluted cities was comparable to the risk associated with nonsmokers being exposed to second-hand smoke over a long period of time."

The researchers also looked at air particulate reports for the regions involved. Their finding: sulfur oxide pollution -- from automobile exhaust -- was significantly associated with all deaths including heart disease and lung cancer.

Pope admits that there may be unaccounted-for factors that affect this seemingly strong link between air pollution and disease.