Deficits in Bone Geometry in Growth Hormone-Deficient Prepubertal Boys Revealed by High-Resolution Peripheral Quantitative Computed Tomography

Abstract

<b><i>Introduction:</i></b> Although growth hormone (GH) is essential for attainment of peak bone mass, bone health in prepubertal children with GH deficiency is not routinely evaluated. The objective of this study was to evaluate bone microarchitecture in GH-deficient (GHD) boys using high-resolution peripheral quantitative computed tomography (HR-pQCT). <b><i>Methods:</i></b> Fifteen control and fifteen GHD, GH naïve pre-pubertal boys were recruited for a case-control study at a major academic center. Subjects with panhypopituitarism, chromosomal pathology, chronic steroids, or stimulant use were excluded. Volumetric bone mineral density (vBMD; total, cortical, and trabecular), bone geometry (total, cortical and trabecular cross-sectional area, cortical perimeter), bone microarchitecture, and estimated bone strength of the distal radius and tibia were assessed by HR-pQCT. Areal BMD and body composition were assessed by DXA. Insulin-like growth factor 1 (IGF-1), osteocalcin, C telopeptide, and P1NP levels were measured. <b><i>Results:</i></b> GHD subjects had a significantly smaller cortical perimeter of the distal radius compared to controls (<i>p</i> < 0.001), with the difference in cortical perimeter persisting after adjusting for height <i>z</i> score, age, lean mass, and 25-hydroxyvitamin D level (<i>p</i> < 0.05).<i></i>No significant differences were found in vBMD. No significant differences were found in microarchitecture, estimated strength, areal BMD, body composition, or bone turnover markers. Analysis showed significant positive correlations between IGF-1 levels and cortical parameters. <b><i>Discussion/Conclusions:</i></b> Prepubertal GHD boys had deficits in bone geometry not evident with DXA. Larger prospective/longitudinal HR-pQCT studies are needed to determine the extent of these deficits, the need for routine bone evaluation, and the timing of GH replacement for prevention or restoration of these deficits.

Low Serum 25-hydroxyvitamin D Level Does Not Adversely Affect Bone Turnover in Prepubertal Children

“…Studies have suggested a possible interaction between 25-hydroxyvitamin D and IGF-1 during prepubertal bone mineral accrual [2,3]. The key "bone trophic hormones", growth hormones (GH) and IGF-1, are essential for achieving peak bone mass [4,5]. GH acts directly on bone cells and stimulates IGF-1 to increase bone formation through the enhancement of osteoblasts proliferation, differentiation, and activity [4].…”