Low Skeletal Muscle Mass Accompanied by Abdominal Obesity Additively Increases the Risk of Incident Type 2 Diabetes

Context: Low skeletal muscle mass often accompanies abdominal obesity in the aging process. Objective: We aimed to investigate the effect of reduced skeletal muscle mass and its interaction with abdominal obesity on incident type 2 diabetes. Methods: This retrospective longitudinal study included 36 304 diabetes-free Koreans who underwent 2 or more health checkups annually or biannually. Appendicular skeletal muscle mass was measured by bioelectrical impedance analysis and was presented as a skeletal muscle mass index (SMI) adjusted for body weight. Presarcopenia was defined as an SMI less than 1 SD of the sex-specific mean for a healthy young reference group. Abdominal obesity was defined using waist circumference greater than or equal to 90 cm for men and greater than or equal to 85 cm for women. Participants were classified into 4 groups of normal, presarcopenia alone, abdominal obesity alone, and presarcopenic obesity according to initial body composition. Results: The cumulative incidence of diabetes was 9.1% during the 7-year follow-up. Compared with the highest tertile, the lowest sex-specific SMI tertile was significantly associated with a greater risk of incident type 2 diabetes (adjusted hazard ratio [HR] = 1.31; 95% CI, 1.18-1.45) in a fully adjusted model. Presarcopenic obesity significantly increased incident diabetes risk (adjusted HR = 1.57; 95% CI, 1.42-1.73) compared with normal body composition, presarcopenia alone, or abdominal obesity alone. Conclusion: Low skeletal muscle mass and its coexistence with abdominal obesity additively increased the risk of incident type 2 diabetes independent of the glycometabolic parameters.