Relationships between osteoprotegerin (OPG), receptor activator of nuclear factor kappaB ligand (RANKL), and growth hormone (GH) secretory status in short children.

UNLABELLED: GH deficiency places children at risk for decreased bone density and increased fracture rates. The RANKL/RANK/OPG system plays an important role in linking bone formation to bone resorption. Although OPG is thought to be secreted as a compensatory response to states of low bone density, its concentrations have not been found to differ significantly between GH-deficient, acromegalic, and healthy adults.

AIM: To evaluate the associations between OPG and RANKL serum levels and GH secretory status in children.

CHILDREN: 54 short children were recruited.

METHODS: Serum OPG and RANKL, IGF-I, IGFBP-3, stimulated GH levels, bone DEXA results, and growth velocity were assessed. Regression modeling was used to evaluate significant predictors of OPG and RANKL levels.

RESULTS: There were no significant differences in OPG and RANKL serum levels or bone DEXA results between GH-deficient and GH-sufficient children. A statistically significant quadratic relationship between OPG and IGFBP-3 concentrations was observed.

CONCLUSIONS: IGFBP-3 was found to be the only significant predictor of OPG serum levels, allowing us to speculate that increased OPG levels may represent a compensatory response to the missing anabolic actions of IGF-I and/or GH in children with GH deficiency.