Association between environmental tobacco smoke exposure and risk of type 2 diabetes mellitus in Chinese female never-smokers: a population-based cohort study.

Evidence for the association between environmental tobacco smoke (ETS) exposure and the risk of type 2 diabetes mellitus (T2DM) is limited. The aim of this study was to investigate this association in female never-smokers.We analyzed 28 177 female participants of the China Kadoorie Biobank (CKB) in Suzhou area, who were never-smokers without diabetes. ETS exposure was defined as exposing to other people's tobacco smoke either at home, workplace or in public places at least 1 day/week. Cox proportional hazard regression models were used to assess the association between ETS exposure and incident T2DM, according to the frequency and duration of ETS exposure, respectively.A total of 774 incident cases of T2DM were identified during a median 7.3 years follow-up. Compared with the no ETS exposure, hazard ratios (95% confidence intervals) for all ETS exposure, the daily and ≥14h/week ETS exposure were 1.17 (1.00-1.37), 1.23 (1.04-1.46) and 1.25 (1.03-1.53), respectively. Moreover, a positive dose-response relationship was observed between ETS exposure level and T2DM (all P<0.05 for trend).This prospective study suggested that ETS exposure increased the risk of T2DM incidence with dose-response relationship in female never-smokers. Thus, reducing ETS exposure may benefit in decreasing the burden of T2DM in Chinese females. This article is protected by copyright. All rights reserved.