Secondhand Smoke, Pollution Pose Cardiovascular Risks

While smokers have most risk, study finds secondhand exposures pose mortality risks too

WEDNESDAY, Sept. 2 (HealthDay News) -- While risks of cardiovascular mortality are greatest for active cigarette smokers, the relative risk for people exposed to secondhand smoke or air pollution is significant, according to a study published online Aug. 31 in Circulation.

C. Arden Pope III, Ph.D., of Brigham Young University in Provo, Utah, and colleagues analyzed data from the American Cancer Society's 1982 Cancer Prevention Study II. The researchers used proportional hazards regression models to estimate mortality risks from ischemic heart disease, cardiovascular disease, and cardiopulmonary disease in the cohort associated with active cigarette smoking, secondhand smoke, and air pollution (adjusted for occupational exposures, education, marital status, body mass, alcohol consumption and diet).

The researchers estimated the adjusted relative risk for active smoking ranged from 1.63 to 1.97 for ischemic heart disease, 1.64 to 2.03 for cardiovascular disease, and 1.72 to 2.17 for cardiopulmonary disease. For secondhand smoke, the relative risk ranged from 1.16 to 1.26 for cardiovascular disease and 1.24 to 1.28 for ischemic heart disease. For ambient air pollution, the relative risks were 1.18 for ischemic heart disease, 1.12 for cardiovascular disease, and ranged from 1.09 to 1.31 for cardiopulmonary disease.

"Relatively low levels of fine particulate exposure from either air pollution or secondhand cigarette smoke are sufficient to induce adverse biological responses increasing the risk of cardiovascular disease mortality," the authors write. "The exposure-response relationship between cardiovascular disease mortality and fine particulate matter is relatively steep at low levels of exposure and flattens out at higher exposures."

Two of the study authors reported receiving grant support for related research from the Health Effects Institute. The author of an accompanying editorial reported receiving a grant funded by the U.S. Environmental Protection Agency.

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