Sex differences in lung-cancer risk associated with cigarette smoking.

The importance of cigarette smoking as a risk factor for specific histologic types of lung cancer in men and women has been examined in a case-control analysis of data from the Cancer Surveillance Program of Orange County, a population-based registry. Smoking habits were abstracted from medical records for 1153 men and 833 women diagnosed with primary lung cancer in 1984-1986 and 1851 men and 1656 women aged 30 or older diagnosed with cancers not associated with smoking. Ninety-six percent of men and 89% of women with lung cancer were current or former cigarette smokers, as compared with 55% of men and 34% of women with other cancers. The age and ethnicity-adjusted odds ratios (OR) for ever-smoking were 19.7 for men and 15.0 for women. Men and women who smoked 2 or more packs per day experienced nearly equal risks. Comparison of the most common cell types showed that women smokers had equal or lower ORs for squamous-cell carcinoma and adenocarcinoma, but higher OR for small-cell carcinoma, as compared with men smokers. While the smoking-associated OR were equal for small-cell and squamous-cell carcinomas in men, the OR for women were significantly higher for small-cell carcinoma than for squamous-cell carcinoma.