Objective: The study intent was to examine long-term effects on bone mass of 3 or 6 months of nafarelin therapy for endometriosis.
Study design: Women with established endometriosis (N = 173) were randomized to receive nafarelin (200 micrograms intranasally twice a day) for either 3 or 6 months in a double-blind fashion. Bone mineral density was measured by dual energy x-ray absorptiometry at lumbar spine and proximal femoral sites for 18 months.
Results: Bone mineral density declined at spinal and femoral sites similarly in both 3- and 6-month treatment groups. There was a partial, but incomplete, return to baseline levels after 12 to 15 months of follow-up. The recovery of bone mass was more complete in subjects with higher dietary calcium intakes.
Conclusion: Nafarelin therapy for endometriosis results in a sustained loss of spinal and femoral bone density, particularly in women with lower calcium intakes.