Bone mineral density during 3 years of growth hormone in previously GH-treated young adults with PWS

Objective: In children with Prader-Willi syndrome (PWS), growth hormone (GH) treatment has positive effects on bone mineral density (BMD). Two 1-year studies did not show a difference between GH or placebo on BMD in young adults with PWS. However, there are no studies investigating BMD during longer-term GH treatment in young adults with PWS. Design: Open-label, a prospective study in 43 young adults with PWS. Methods: BMD of the total body (BMDTBSDS) and lumbar spine (BMAD(LS)SDS) measured by DXA. Results: In the total group, estimated mean (95% CI) of BMDTB remained similar during 3 years of GH, being -0.76 (-1.11 to -0.41) SDS at start and -0.90 (-1.27 to -0.54) SDS after 3 years (P = 0.11), as did BMAD(LS), being -0.36 (-0.72 to 0.01) SDS and -0.46 (-0.77 to -0.16) SDS, respectively (P = 0.16). In men, there was a significant decrease in BMDTBSDS during 3 years of GH, while BMAD(LS)SDS remained similar. In women, both BMDTBSDS and BMAD(LS)SDS remained similar. BMDTBSDS was associated with female sex, lean body mass and age. The majority of patients received sex steroid replacement therapy (SSRT). Conclusions: During 3 years of combined GH and SSRT treatment, BMD remained stable in the normal range in young adults with PWS. However, men showed a decline in BMDTBSDS, probably due to insufficient SSRT. We recommended to continue GH treatment in young adults with PWS and to start SSRT during adolescence unless puberty progresses normally.