The first direct medical evidence that secondhand smoke can damage the lungs of non-smokers has been produced by an international team led by researchers at Harvard University.
The team performed autopsies on the 30 non-smoking women and found that the lungs from the wives of smokers contained a "significantly higher" number of precancerous abnormalities _ such as cellular proliferation and damage _ than did lungs from the wives of non-smokers.
Previous studies showing a higher incidence of lung cancer among wives and children of smokers have been based on statistical evidence and suggest that at least 4,000 people die fromlung cancer each year as the result of secondhand smoke.
But the tobacco industry has argued that the reported link between lung cancer and passive smoking could come from biases in the collection of that epidemiological data.
The new study, reported in today's Journal of the American Medical Association, appears to show that those statistics were not biased, proponents say.
"It is a pathfinding study," said Dr. Morton Lippman, a professor of environmental medicine at the New York University Medical Center who recently led an Environmental Protection Agency panel evaluating the hazards of secondhand smoke.
A preliminary version of that risk assessment, released in June, concludes that environmental tobacco smoke causes lung cancer in non-smoking adults, increases the risk of respiratory infection in children and exacerbates symptoms in children with asthma.