Muscle-Bone Crosstalk and Metabolic Dysregulation in Children and Young People Affected with Type 1 Diabetes: Mechanisms and Clinical Implications

Pediatric type 1 diabetes (T1D) disrupts musculoskeletal development during critical windows of growth, puberty, and peak bone mass accrual. Beyond classic micro- and macrovascular complications, accumulating evidence shows a dual burden of diabetic bone disease-reduced bone mineral density, microarchitectural deterioration, and higher fracture risk-and diabetic myopathy, characterized by loss of muscle mass, diminished strength, and metabolic dysfunction. Mechanistically, chronic hyperglycemia, absolute or functional insulin deficiency, and glycemic variability converge to suppress PI3K-AKT-mTOR signaling, activate FoxO-driven atrogenes (atrogin-1, MuRF1), and impair satellite-cell biology; advanced glycation end-products (AGEs) and RAGE signaling stiffen extracellular matrix and promote low-grade inflammation (IL-6, TNF-alpha/IKK/NF-kappa B), while oxidative stress and mitochondrial dysfunction further compromise the bone-muscle unit. In vitro, ex vivo, and human studies consistently link these pathways to lower BMD and trabecular/cortical quality, reduced muscle performance, and increased fractures-associations magnified by poor metabolic control and longer disease duration. Prevention prioritizes tight, stable glycemia, daily physical activity with weight-bearing and progressive resistance training, and optimized nutrition (adequate protein, calcium, vitamin D). Treatment is individualized: supervised exercise-based rehabilitation (including neuromuscular and flexibility training) is the cornerstone of skeletal muscle health. This review provides a comprehensive analysis of the mechanisms underlying the impact of type 1 diabetes on musculoskeletal system. It critically appraises evidence from in vitro studies, animal models, and clinical research in children, it also explores the effects of prevention and treatment.