The Role of Muscular Fitness on Bone Mineral Content and Areal Bone Mineral Density in Youth With Type 1 Diabetes

Context: Type 1 diabetes in youth increases the risk of compromised bone health due to glycemic dysregulation. Muscular fitness may play a role in improving bone health during growth. Objective: This study aimed to investigate the association between muscular fitness and bone health in youth with type 1 diabetes. Methods: A total of 83 young individuals with type 1 diabetes (aged 6-18 years; 44.6% girls) from the Diactive-1 cohort study were followed for 2 years. Dual-energy x-ray absorptiometry whole-body scans were used to assess bone mineral content (BMC) and areal bone mineral density (aBMD) of the total body less head (TBLH), arms, legs, pelvis, and spine. Muscular fitness (handgrip strength, 1 repetition maximum, and muscle power) was assessed with a dynamometer and eGYM devices. Handgrip strength and TBLH bone parameters were age- and sex-standardized using the FitBack Project and BMD Childhood Study, respectively. Results: Linear mixed models showed longitudinal associations of handgrip strength with TBLH-BMC (unstandardized beta coefficient [B] = 17.18, 95% confidence interval [CI] 12.47-21.90) and TBLH-aBMD (B = 0.004, 95% CI 0.002-0.006); RM with TBLH-BMC (B = 20.09, 95% CI 10.88-29.31) and TBLH-aBMD (B = 0.007, 95% CI 0.004-0.011); and power with TBLH-BMC (B = 26.80, 95% CI: 17.31-36.28) and TBLH-aBMD (B = 0.009, 95% CI 0.005-0.012). Comparable results were observed across the other regions (P < .05). Additionally, analyses with standardized data confirmed the relationships of handgrip z-scores with TBLH-BMC z-scores (B = 0.19, 95% CI 0.08-0.30) and TBLH-aBMD z-scores (B = 0.350, 95% CI: 0.210-0.490). Conclusion: In pediatric patients with type 1 diabetes, higher muscular fitness could serve as a complementary therapeutic strategy to preserve or enhance bone health.