Spontaneous reversibility of bone loss induced by gonadotropin-releasing hormone analog

Objective: To verify if a 6-month period of hypoestrogenism due to chronic treatment with GnRH analogue (GnRH-a) causes irreversible bone loss in young women. Design: Controlled clinical study in volunteer women. Setting: Department of Obstetrics and Gynecology, University of Cagliari, Cagliari, Italy. Patients: Twenty-eight women (mean age +/- SE 81.1 +/- 0.99 years) with endometriosis diagnosed by laparoscopy and 25 healthy, normally cycling women of the same age (28.3 +/- 1.14 years). Interventions: In women with endometriosis, six SC implants of the GnRH-a compound, 3.6 mg goserelin acetate depot, were administered every 28 days starting within 15 days of laparoscopy. Compounds interfering with bone metabolism or hormonal formulations were not taken by control women during the entire period of the study. Main Outcome Measure: Evaluation of lumbar bone mineral density at the start of the study and 6, 12, and 30 months later. Results: At the onset of the study, lumbar bone mineral density did not differ in women with endometriosis and control women. Lumbar bone mineral density values significantly decreased after 6 months of GnRH-a treatment. This reduction was still evident 6 months after GnRH-a interruption. However, 24 months after treatment withdrawal, bone mineral density reduction disappeared and bone mineral density values were completely superimposable (+/-0.4%) to those observed before treatment. In contrast, control. women lumbar bone mineral density values did not change during the entire period of observation. Conclusions: These data suggest that GnRH-a treatment for 6 months is not associated with long-term effects on lumbar bone density.