Relation between exposure to environmental tobacco smoke and lung cancer in lifetime nonsmokers.

To assess the relation between exposure to environmental tobacco smoke throughout life and lung cancer in lifetime nonsmokers, the authors conducted in-person interviews with 41 male and 69 female never-smoking lung cancer cases and 117 male and 187 female never-smoking controls between 1983 and 1990 as part of a hospital-based case-control study of tobacco-related cancers. Cases had newly diagnosed, histologically confirmed primary carcinoma of the lung. Controls were matched to cases on age (+/- 5 years), sex, race, hospital, and year of interview. Subjects were asked about environmental tobacco smoke exposure in childhood, in adulthood at home, in different jobs, and in transportation and social situations. In addition to amount smoked by family members in the subject's presence, subjects were asked to rate the intensity of each exposure, and married subjects were asked whether their spouse smoked in the bedroom. Several independent indicators of exposure to smoking by spouses were strongly correlated, thereby increasing confidence in the classification of exposure status. The reproducibility of environmental tobacco smoke variables was good for qualitative measures (yes/no), in agreement with previous studies. There were few associations of exposure in specific settings with lung cancer. Males whose wives smoked had odds ratio of 1.60 (95% confidence interval (CI) 0.67-3.82) and females whose husbands smoked had an odds ratio of 1.08 (95% CI 0.60-1.94). While this study had limited sample size, the pattern of odds ratios shows little indication of an association of environmental tobacco smoke with lung cancer in nonsmokers.