Bone mineral density in children and adolescents with Prader-Willi syndrome: a longitudinal study during puberty and 9 years of growth hormone treatment.

CONTEXT: Longitudinal data on bone mineral density (BMD) in children and adolescents with Prader-Willi Syndrome (PWS) during long-term GH treatment are not available. OBJECTIVE: This study aimed to determine effects of long-term GH treatment and puberty on BMD of total body (BMDTB), lumbar spine (BMDLS), and bone mineral apparent density of the lumbar spine (BMADLS) in children with PWS. DESIGN AND SETTING: This was a prospective longitudinal study of a Dutch PWS cohort. PARTICIPANTS: Seventy-seven children with PWS who remained prepubertal during GH treatment for 4 years and 64 children with PWS who received GH treatment for 9 years participated in the study. INTERVENTION: The children received GH treatment, 1 mg/m(2)/day (≅ 0.035 mg/kg/d). MAIN OUTCOME MEASURES: BMDTB, BMDLS, and BMADLS was measured by using the same dual-energy x-ray absorptiometry machine for all annual measurements. RESULTS: In the prepubertal group, BMDTB standard deviation score (SDS) and BMDLSSDS significantly increased during 4 years of GH treatment whereas BMADLSSDS remained stable. During adolescence, BMDTBSDS and BMADLSSDS decreased significantly, in girls from the age of 11 years and in boys from the ages of 14 and 16 years, respectively, but all BMD parameters remained within the normal range. Higher Tanner stages tended to be associated with lower BMDTBSDS (P = .083) and a significantly lower BMADLSSDS (P = .016). After 9 years of GH treatment, lean body mass SDS was the most powerful predictor of BMDTBSDS and BMDLSSDS in adolescents with PWS. CONCLUSIONS: This long-term GH study demonstrates that BMDTB, BMDLS, and BMADLS remain stable in prepubertal children with PWS but decreases during adolescence, parallel to incomplete pubertal development. Based on our findings, clinicians should start sex hormone therapy from the age of 11 years in girls and 14 years in boys unless there is a normal progression of puberty.

Eight years of growth hormone treatment in children with Prader-Willi syndrome: maintaining the positive effects.

BACKGROUND: The most important reason for treating children with Prader-Willi syndrome (PWS) with GH is to optimize their body composition. OBJECTIVES: The aim of this ongoing study was to determine whether long-term GH treatment can counteract the clinical course of increasing obesity in PWS by maintaining the improved body composition brought during early treatment. SETTING: This was a multicenter prospective cohort study. METHODS: We have been following 60 prepubertal children for 8 years of continuous GH treatment (1 mg/m(2)/d ≈ 0.035 mg/kg/d) and used the same dual-energy x-ray absorptiometry machine for annual measurements of lean body mass and percent fat. RESULTS: After a significant increase during the first year of GH treatment (P < .0001), lean body mass remained stable for 7 years at a level above baseline (P < .0001). After a significant decrease in the first year, percent fat SD score (SDS) and body mass index SDS remained stable at a level not significantly higher than at baseline (P = .06, P = .14, resp.). However, body mass index SDSPWS was significantly lower after 8 years of GH treatment than at baseline (P < .0001). After 8 years of treatment, height SDS and head circumference SDS had completely normalized. IGF-1 SDS increased to +2.36 SDS during the first year of treatment (P < .0001) and remained stable since then. GH treatment did not adversely affect glucose homeostasis, serum lipids, blood pressure, and bone maturation. CONCLUSION: This 8-year study demonstrates that GH treatment is a potent force for counteracting the clinical course of obesity in children with PWS.