Bone Mineral Density and Effects of Growth Hormone Treatment in Prepubertal Children with Prader-Willi Syndrome: A Randomized Controlled Trial

Background: Bone mineral density (BMD) is unknown in children with Prader-Willi syndrome (PWS), but is decreased in adults with PWS. In patients with GH deficiency, BMD increases during GH treatment. Objectives: The aim of the study was to evaluate BMD in children with PWS and to study the effects of GH treatment. Design: We conducted a randomized controlled GH trial. Forty-six prepubertal children were randomized into either a GH-treated group (1.0 mg/m(2) . d) or a control group for 2 yr. At start, 6, 12, and 24 months of study, total body and lumbar spine BMD were measured by dual-energy x-ray absorptiometry, and lumbar spine bone mineral apparent density (BMAD) was calculated. Results: Baseline total body and lumbar spine BMD SD score (SDS) were normal [mean(SD), -0.2SDS (1.1) and -0.4 SDS (1.2), respectively]. BMADSDS, which corrects for short stature, was also normal [mean (SD), 0.40 SDS (1.1)]. Total body BMDSDS decreased during the first 6 months of GH (P < 0.0001), but increased during the second year of treatment. After 24 months of study, total body and lumbar spine BMDSDS, and the BMADSDS did not significantly differ between GH-treated children and randomized controls (P = 0.30, P = 0.44, and P = 0.47, respectively). Results were similar when corrected for body mass index SDS. Repeated measurements analysis showed a significant positive association between IGF-I SDS and total body and lumbar spine BMDSDS, but not with BMADSDS. Conclusions: Our results show that prepubertal children with PWS have a normal BMD. GH treatment had no effect on BMD, except for a temporary decrease of total body BMDSDS in the first 6 months. (J Clin Endocrinol Metab 94: 3763-3771, 2009)