Abstract
PURPOSE: The gender differential evidence of the association between shift work and type 2 diabetes risk remains scarce. This longitudinal study determines whether the association between shift-work exposure and type 2 diabetes risk and abnormal fasting plasma glucose (FPG) differs according to gender; the study aims to find the association between shift work and changes in physiological, behavioral, and psychosocial stress. PATIENTS AND METHODS: This retrospective cohort study was conducted among 5947 workers (4647 female and 1300 male) aged ≤60 years old in Bangkok, Thailand. Participants required a normal FPG level (<100 mg/dL) at baseline and at least two health check-up results from 2009 to 2016. Shift-work exposure history was assessed using a self-administered questionnaire; FPG levels were measured annually. Cox proportional hazard models were used to assess the aforementioned association. RESULTS: During the follow-up period, 1470 new abnormal FPG and 154 new type 2 diabetes cases developed. Stratified analysis of male workers' data revealed an association was significant in the unadjusted model, which tended to be stronger after adjustment for demographic data and the baseline values of anthropometric and biochemical parameters. This was the case both for type 2 diabetes [Hazard Ratio (HR) (95% Confidence Interval (CI))=2.98 (1.58-5.62)] and abnormal FPG [HR (95% CI)=1.86 (1.43-2.41)]; this association was less obvious among women. CONCLUSION: Shift work is a risk factor for type 2 diabetes and abnormal FPG; this risk is gender differential, being more pronounced in men. Preventive measures aiming at ameliorating shift work induced type 2 diabetes risk should pay more attention to men.