The Association between Bone Age Advancement and Insulin Resistance in Prepubertal Obese Children

Objective: Obesity is associated with bone age (BA) advancement, but the underlying mechanisms remain unclear. The objective of this study was to investigate the association between BA maturation and insulin levels in obese children. Methods: In this cross-sectional study of 93 prepubertal obese children, anthropometric data and hormonal values were measured. Subjects were divided into 2 groups based on the difference between BA and chronological age (CA) (noted as BA-CA). Results: The study population included 39 (41.9 %) males and 54 (58.1 %) females with a mean age of 7.4 +/- 1.5 years. The advanced bone age group defined as BA-CA > 1 year (n = 44) had significantly higher HOMA-IR and fasting insulin levels, and lower quantitative insulin sensitivity check index (QUICKI). BA-CA was significantly correlated with fasting insulin (r = 0.255, P = 0.014), HOMA-IR (r = 0.230, P = 0.027), and QUICKI (r = -0.301, P = 0.003). Also, height SDS was significantly associated with Delta BA-CA (r = 0.417, P < 0.001). In the multiple regression analysis, HOMA-IR was identified as a significant independent predictor of BA-CA. Conclusion: Bone age is more advanced in obese children with hyperinsulinemia and insulin resistance. These findings suggest that insulin may affect skeletal maturation.