The effect of growth hormone treatment on bone mineral density in prepubertal girls with Turner syndrome: a multicentre prospective clinical trial.

BACKGROUND

Patients with Turner syndrome (TS) are treated with GH to increase adult height. Although it is well established that GH promotes longitudinal bone growth, the effects of GH treatment on bone density are less clear.

OBJECTIVE

To determine how GH treatment affects trabecular bone mineral density (BMD) in girls with TS at prepubertal ages in a prospective multicentre study.

PATIENTS AND METHOD

Twenty-two patients with TS in the prepubertal period with a mean age of 9.8 +/- 2.5 (range 3.6-12.8) years were included in the study. All girls with TS underwent measurement of areal BMD using dual-energy X-ray absorptiometry (DXA) to obtain pretreatment anteroposterior (AP) lumbar spine values at L1-L4. Patients received GH (Genotropin) subcutaneously for 1 year at a dose of 0.05 mg/kg/day. Height and weight were measured at 3-monthly intervals. The AP lumbar spine areal BMD was remeasured using the same technique after 1 year of treatment. Lumbar spine BMD Z-scores and volumetric BMD (vBMD) Z-scores were calculated using national standards.

RESULTS

The height SDS of our cases showed a significant increase with GH therapy. The pretreatment lumbar spine (L1-L4) BMD Z-score was -1.2 +/- 1.2 SD and the vBMD Z-score was -0.8 +/- 1.6 SD. There were no significant changes in these values after 1 year of GH treatment. Prepubertal TS girls more than 11 years of age had lower vBMD Z-scores (-1.7 +/- 1.7 SD) than the girls aged less than 11 (-0.1 +/- 1.0 SD) (P < 0.05) at the onset of therapy. No significant changes were observed in these values after 1 year of GH therapy.

CONCLUSIONS

Osteopaenia becomes apparent in prepubertal TS patients as they reach pubertal age. BMD evaluation may be necessary in these prepubertal TS girls at diagnosis. Short-term GH therapy in these TS patients does not have a significant effect on bone density when measured at a site with a predominance of trabecular bone.