Aims: Data are limited regarding how shift work is linked to the development of type 2 diabetes, especially among workers at high risk of diabetes. We examined the risk of diabetes according to shift-work conditions over several years among Japanese adults.
Methods: This prospective study enrolled 17,515 workers (age 40-78 years). Shift work was self-reported at annual health examinations over time from 2004 to 2017 and categorized as shift workers or non-shift workers. Diabetes was defined as fasting plasma glucose, random glucose, HbA1c, and self-reported use of antidiabetic medications. The association of shift work and diabetes was quantified using Cox regression.
Results: During a follow-up of 8.1 years in median, 2071 incident cases of diabetes were documented. Compared with non-shift work, shift work showed a significantly elevated hazard ratios of developing diabetes. Shift work showed a 19% (95% confidence intervals: 3-37%) higher hazard ratios for diabetes, after adjustment for demographic-, cardiometabolic-, and work-related factors. Further adjustment for lifestyle factors and body mass index did not materially change this association (a 16% increase; 95% confidence intervals, 1-34%). This relationship was replicated among workers with prediabetes.
Conclusions: Engaging in shift work may increase the risk of developing diabetes independently of lifestyle factors and body mass index, even among prediabetic workers.
Keywords: Diabetes; Prediabetes; Prevention; Repeated measures; Shift work.
© 2021. Springer-Verlag Italia S.r.l., part of Springer Nature.