Environmental tobacco smoke and lung cancer: A case-control study in Germany

To assess the association between exposure to environmental tobacco smoke ( ETS) and lung cancer, the authors personally interviewed 292 lifelong nonsm oking lung cancer cases (recruited from 15 hospitals in the study area) and 1,338 nonsmoking controls (randomly selected by population registries) bet ween 1990 and 1996 in Germany. Subjects were asked by a standardized questi onnaire about exposure to ETS in childhood, by spouse, at work, and in tran sportation and social settings. Several indicators of these different sourc es of exposure were investigated, using not or low exposed subjects as the reference category. The most informative quantification index was weighted duration of exposure (hours x level of smokiness). No effect of ETS exposur e during childhood and no clear effect of spousal ETS were observed. Howeve r, for the highest category of exposure, clear effects of ETS at the workpl ace (odds ratio (OR) = 1.93; 95% confidence interval (CI), 1.04, 3.58), in vehicles (OR = 2.64; 95% CI: 1.30, 5.36), and from all sources combined (OR = 1.39; 95% CI: 0.96, 2.01) were found. Adjustment for occupational carcin ogens, radon, and diet did not appreciably change the results. These findin gs suggest that exposures to high levels of ETS at the workplace and in oth er public indoor settings appear to be important risk factors for lung canc er risk in nonsmokers.