Over the past decade, the scientific community has turned up conflicting evidence regarding whether cigarettes impart a greater risk of lung cancer to women than to men. In the largest comparison to date, researchers now report that the sexes share a roughly equal risk of developing the cancer from smoking.
The scientists also analyzed data from six other studies and arrived at the same conclusion. The findings appear in the June 2 Journal of the National Cancer Institute.
“This paper does a good job of putting the debate to rest,” says Thomas V. Perneger, a physician at the University of Geneva in Switzerland, who didn’t participate in the study.
Several studies in the 1990s had suggested that women who smoked fared worse than male smokers. However, those studies documented smoking behavior on the basis of people’s recollections, says Diane Feskanich, an epidemiologist at Harvard Medical School and Brigham and Women’s Hospital in Boston. She also notes that some studies failed to compare women and men head-to-head and instead examined differences in lung cancer rates between smokers and nonsmokers within each gender.
Feskanich and her colleagues used data from two massive studies—one of female nurses and one of men in various health professions—in which the participants contributed updates on their health and lifestyle practices every 2 years. The researchers analyzed the data reported between 1986 and 2000, comparing smoking behavior and the incidence of lung cancer for each group. The analysis accounted for differences between the men and women such as body weight, height, age, cigarettes smoked per day, age at the start of smoking, and time since former smokers had quit.
The results indicate that women smokers are 10 percent more likely to develop lung cancer, but this difference is small enough that it could be due to chance, says Feskanich. Moreover, even if the women’s excess rate of contracting cancer has a valid biological basis, she says, the gender difference pales in comparison to the danger imparted by smoking itself, which boosts anybody’s risk of lung cancer by 10- to 20-fold over that of a nonsmoker.
When the researchers pored over six other studies that had tracked people’s smoking behaviors, the team found no excess risk of lung cancer or death due to lung cancer in women.
“Gender is a bit of a hot topic, but it is not necessarily relevant for all health problems,” Perneger says. Even so, gender might be relevant in designing smoking-prevention programs, just as it has been in marketing cigarettes, he says.