Role of Osteocalcin in the Regulation of Glucose Metabolism in Children and Adolescents with Obesity

Background: Osteocalcin (OC) is a bone-derived hormone increasingly implicated in glucose and lipid metabolism. Although its metabolic role has been extensively investigated in adults, evidence in pediatric populations remains limited. This exploratory study aimed to evaluate the relationship between serum OC levels and glucose metabolism in children and adolescents with obesity. Methods: A single-center, retrospective study was conducted in a cohort of pediatric patients with essential obesity. Auxological and biochemical parameters were assessed, including fasting glucose, insulin, lipid profile, liver enzymes, thyroid function, calcium–phosphorus metabolism, vitamin D3, parathormone (PTH), C-terminal telopeptide of type I collagen (CTX), and OC. Insulin resistance was evaluated using the HOMA-IR index (>2.5 considered positive). Correlation analyses were performed to assess the associations between serum OC levels and metabolic, biochemical, and clinical parameters. Results: Twenty-two of 33 patients (66.7%) had insulin resistance (HOMA-IR > 2.5) despite preserved glucose tolerance. Mean fasting glucose was 88.1 ± 10.83 mg/dL, fasting insulin 24.9 ± 13 μU/mL, and mean serum OC 112.1 ± 56.1 ng/mL. Serum OC levels were positively correlated with fasting insulin (r = 0.41, p = 0.023) and HOMA-IR (r = 0.46, p = 0.013). Conclusions: In children with obesity and preserved glucose tolerance, higher serum OC levels were associated with insulin resistance. Further studies in larger pediatric cohorts are needed to clarify this association and evaluate the potential role of OC as a biomarker of early metabolic dysregulation.