摘要：Objectives. We sought to quantitatively evaluate the association between work-place environmental tobacco smoke exposure and lung cancer. Methods. We performed a meta-analysis in 2003 of data from 22 studies from multiple locations worldwide of workplace environmental tobacco smoke exposure and lung cancer risk. Estimates of relative risk from these studies were analyzed by fitting the data to fixed and mixed effects models. Analyses of highly exposed workers and of the relationship between duration of exposure and lung cancer were also performed. Results. The meta-analysis indicated a 24% increase in lung cancer risk (relative risk [RR]=1.24; 95% confidence interval [CI]=1.18, 1.29) among workers exposed to environmental tobacco smoke. A 2-fold increased risk (RR=2.01; 95% CI=1.33, 2.60) was observed for workers classified as being highly exposed to environmental tobacco smoke. A strong relationship was observed between lung cancer and duration of exposure to environmental tobacco smoke. Conclusions. The findings from this investigation provide the strongest evidence to date that exposure to environmental tobacco smoke in the workplace is associated with an increased risk of lung cancer. Exposure to environmental tobacco smoke (ETS) has been recognized as a cause of human cancer by the US Surgeon General, 1 the National Institute for Occupational Safety and Health, 2 the US Environmental Protection Agency, 3 the California Environmental Protection Agency, 4 the National Health and Medical Research Council of Australia, 5 the Great Britain Department of Health, 6 and most recently, the International Agency for Research on Cancer. 7 Evidence for this association has come primarily from studies of nonsmokers who are married to a smoker, and meta-analyses of these studies have demonstrated strong and consistent evidence for an association. 3 , 8 , 9 Demonstrating an association between workplace ETS exposure and lung cancer risk has been more difficult. Early meta-analyses failed to demonstrate an association between workplace ETS exposure and lung cancer risk among nonsmokers, 10 – 14 but a statistically significant association has been reported in the 3 most recently published meta-analyses. 15 – 17 We sought to extend the previous meta-analyses by including additional studies and by conducting analyses stratified by level of exposure, which was not performed in the previous meta-analyses.
