[Systematic review of studies of workplace exposure to environmental tobacco smoke and lung cancer risk].

BACKGROUND AND OBJECTIVE: It has been reported that there was a close relationship between lung cancer risk and environmental tobacco smoke at workplace. The aim of this study is to explore the relationship between workplace environmental tobacco smoke exposure and lung cancer risk among non-smoking subjects. METHODS: By searching Medline, CENTRAL (the Cochrane central register of controlled trials), EMBASE, CBM, CNKI and VIP et al, we collected both domestic and overseas published documents on workplace environmental tobacco smoke exposure and lung cancer risk. Random or fixed effect models were applied to conduct systematic review on the study results, the combined odds ratio (OR) and the 95% confidence interval (CI) were calculated as well. RESULTS: 22 reports were included into the combined analysis, which indicated that 25% lung cancer risk was increased by exposing to workplace environment tobacco smoke (OR=1.25, 95%CI: 1.13-1.39, P < 0.001). For female the increased risk was 22% (OR=1.22, 95%CI: 1.05-1.42, P=0.011). For male the increased risk was 54%, but it does not reach the statistical significance (OR=1.54, 95%CI: 0.74-3.18, P=0.247). CONCLUSIONS: Workplace environmental tobacco smoke exposure is an important risk factor of lung cancer risk among non-smoking subjects. Especially for non-smoking women who expose to workplace environment tobacco smoke have a close relationship with lung cancer.