Heart Assn. Questions Validity of Second-hand Smoke Study; Study on Second-hand Smoke's Role in Chronic Diseases Based on Flawed Science

5/15/2003

From: Charles Hodges, Charles.Hodges@heart.org, or Eric Bolton, Eric.Bolton@heart.org, both of the American Heart Association, 202-785-7900

WASHINGTON, May 15 -- A new study about second-hand smoke and health is seriously flawed and contradicted by decades of credible scientific research that clearly and irrefutably shows a connection between passive smoking and serious health problems, according to the American Heart Association. The study, "Environmental tobacco smoke and tobacco related mortality in a prospective study of Californians, 1960-98," contends that there is little or no correlation between environmental tobacco smoke, also known as second-hand tobacco smoke, and death from various diseases like coronary heart disease and lung cancer. The study will be published in the May 17 issue of the British Medical Journal.

"Respected, science-based organizations have agreed for over twenty years that second-hand smoke is linked to coronary heart disease, lung cancer and respiratory diseases," said Robert O. Bonow, M.D., president of the American Heart Association. "Credible health organizations from around the world, including the U.S. Environmental Protection Agency, the California Environmental Protection Agency, the World Health Organization and several U.S. Surgeons General, have all concluded that second-hand smoke is responsible for thousands of deaths each year."

Recent evidence has added to this scientific consensus. Just last month, researchers in Helena, Montana, showed that the incidence of heart attacks dropped by 60 percent following the city's adoption of a smoke-free policy in local restaurants and bars.

Chief among the scientific concerns with the study is that the measure of exposure to second-hand smoke was whether or not a person was married to a smoker. "The conclusion that there was no measurable difference in mortality between people married to smokers and those married to non-smokers during the period 1960-1998 implies that living with a non-smoker constituted no exposure to second-hand smoke," Bonow said.

"Participants were enrolled in 1959, when exposure to second-hand smoke was so pervasive that virtually everyone was exposed to second-hand smoke, whether or not they were married to a smoker," said Bonow. This is especially true for data from the 1960s, the 1970s, and even the 1980s, because of the prevalence of second-hand smoke in many venues outside the home, such as offices, restaurants, bars, even airlines and trains, during these decades. Indeed, the concept of "environmental tobacco smoke" was not even acknowledged at the time this study was begun.

Another concern about the study involves its source of funding. The authors received funding from the tobacco industry. "Although acceptance of tobacco industry funding does not, in and of itself, prove malicious intent or incompetent research, when the result of that funding is a study that offers conclusions contrary to the consensus of the world's scientific community, it may be necessary to question whether the design of the study was adequate and appropriate. It would seem the only studies that have not found a correlation between second-hand smoke and heart disease and lung cancer are those funded by the tobacco industry," Bonow concluded.