Higher Muscle Mass Protects Women with Gestational Diabetes Mellitus from Progression to Type 2 Diabetes Mellitus

BACKGROUND: We evaluated whether postpartum muscle mass affects the risk of type 2 diabetes mellitus (T2DM) in Korean women with gestational diabetes mellitus (GDM). METHODS: A total of 305 women with GDM (mean age, 34.9 years) was prospectively evaluated for incident prediabetes and T2DM from 2 months after delivery and annually thereafter. Appendicular skeletal muscle mass (ASM) was assessed with bioelectrical impedance analysis at the initial postpartum visit, and ASM, either divided by body mass index (BMI) or squared height, and the absolute ASM were used as muscle mass indices. The risk of incident prediabetes and T2DM was assessed according to tertiles of these indices using a logistic regression model. RESULTS: After a mean follow-up duration of 3.3 years, the highest ASM/BMI tertile group had a 61% lower risk of incident prediabetes and T2DM compared to the lowest tertile group, and this remained significant after we adjusted for covariates (adjusted odds ratio, 0.37; 95% confidence interval [CI], 0.15 to 0.92; P=0.032). Equivalent findings were observed in normal weight women (BMI <23 kg/m(2)), but this association was not significant for overweight women (BMI ≥23 kg/m(2)). Absolute ASM or ASM/height(2) was not associated with the risk of postpartum T2DM. CONCLUSION: A higher muscle mass, as defined by the ASM/BMI index, was associated with a lower risk of postpartum prediabetes and T2DM in Korean women with GDM.