Poor toe flexor strength, but not handgrip strength, is associated with the prevalence of diabetes mellitus in middle-aged males

Previous studies suggested that reduced muscular strength was one of the potential predictor of prevalence of diabetes mellitus. The purpose of this study was to investigate the association between toe flexor strength (TFS) and handgrip strength (HGS) and the prevalence of diabetes mellitus. Cross-sectional analysis was conducted using data from 1,390 Japanese males (35-59 years). TFS and HGS were measured and medical examinations undertaken. The prevalence of diabetes mellitus was defined as fasting blood glucose >= 126 mg/dL, glycated hemoglobin >= 6.5% (48 mmol/mol), and/or current use of anti-diabetes mellitus drugs. A total of 114 participants had diabetes mellitus. TFS in participants with diabetes mellitus was significantly lower than that in persons not suffering from diabetes mellitus but HGS was not. Odds ratio (OR) and 95% confidence interval (CI) per 1-standard deviation-increase in muscular strength measurements for the prevalence of diabetes mellitus were obtained using a multiple logistic regression model. Prevalence of diabetes mellitus was inversely related to TFS (OR 0.769, 95% CI 0.614-0.963), TFS/body mass (BM) (0.696, 0.545-0.889) and TFS/body mass index (BMI) (0.690, 0.539-0.882) after adjustment of covariates. Such associations were not observed in HGS (OR 0.976, 95% CI 0.773-1.232), HGS/BM (0.868, 0.666-1.133) or HGS/BMI (0.826, 0.642-1.062). These results suggested that poor TFS was associated with an increased prevalence of diabetes mellitus independent of visceral fat accumulation, but HGS was not, in middle-aged males. TFS may be a better marker for the prevalence of diabetes mellitus than HGS.