Abstract
Esophageal cancer continues to pose a significant public health issue in areas with increased incidence rates such as China. Although involuntary smoking was defined as a group 1 carcinogen for lung cancer, few studies have explored the impact of environmental tobacco smoking (ETS) on esophageal cancer. In this paper, we examined the association between ETS and esophageal cancer in high-risk groups in Jiangsu Province, China. Epidemiologic data were collected for 2969 newly diagnosed cases and 8019 population controls including exposure to active/passive smoking and risk factors. The unconditional logistic regression model and the semi-Bayes (SB) method were applied to assess adjusted odds ratios (ORs) and confidence intervals (CIs). ETS exposure (ever vs. never) was positively associated with esophageal cancer with an SB-adjusted OR (95% CI) of 1.44 (1.31-1.58) among overall population, and 1.56 (1.35-1.82) among non-smokers (i.e., non-active smokers), with corresponding population attributable fractions of 15.0% (95% CI: 10.3%-18.9%) and 12.1% (95% CI: 8.8%-19.8%), respectively. The association was more prominent in men at work and in women at home, with SB-adjusted OR (95% CI) of 1.36 (1.17-1.58) and 1.61 (1.35-1.58), respectively. A dose-response relationship between ETS exposure and the disease was detected across the entire population as well as in non-smokers. This is the largest population-based case-control study of ETS and esophageal cancer and the first study to evaluate such association among non-smokers in a Chinese population. We recommend strengthening the ongoing anti-tobacco public health initiatives in China with a particular emphasis on creating a tobacco-free work/home environment.