Strength training and risk of type 2 diabetes in a Japanese working population: A cohort study

Abstract

Aims/IntroductionMuscle strength training has been suggested to improve glucose metabolism; however, epidemiological evidence regarding strength training's effects on diabetes risk is scarce. We prospectively examined the association between strength training and the risk of type 2 diabetes in Japanese men and women.Materials and MethodsThe sample included health checkups on 26,630 Japanese male and female workers aged 30–64 years without diabetes at baseline. Weekly time spent on strength training was elicited using a self-reported questionnaire. Type 2 diabetes was diagnosed based on hemoglobin A1c, fasting glucose, random plasma glucose and self-report in an annual health checkup. Hazard ratio (HR) and its 95% confidence interval (CI) for incident diabetes was estimated using a Cox proportional hazards model.ResultsDuring a mean follow up of 5.2 years with 139,748 person-years, 1,770 individuals developed diabetes. Age- and sex-adjusted HR for diabetes was 0.58 (95% CI 0.42–0.79) in those who engaged in strength training compared with those who engaged in no strength training. After further adjusting for potential confounders, the corresponding HR was 0.66 (95% CI 0.48–0.90). Additional adjustment for body mass index did not materially change the result; the HR was 0.70 (95% CI 0.51–0.96). The association was more pronounced in individuals aged 50 years or older than those aged <50 years, although the difference in the association by age was not significant.ConclusionsThese results suggest that engagement in strength training could help to reduce the risk of type 2 diabetes in a Japanese working population.