The effects of nafarelin and danazol on vertebral trabecular bone mass in patients with endometriosis

Single and dual-energy quantitative computed tomography (QCT) were used to measure spinal trabecular bone mineral content in 24 women treated with either nafarelin (15 patients) or danazol (nine patients) for endometriosis. Significant loss of bone mineral (-9.6 g/l; -5.9% P less than 0.001) was demonstrated after 6 months' treatment with nafarelin. This loss was reversible with no significant difference in the bone mineral measurement made before treatment and that made at 6 months after treatment was stopped (difference -1.95 g/l, NS). A small but statistically significant (+2.2 g/l, P less than 0.05) increase in bone mineral was measured in the group of patients treated with danazol for 6 months. The dual-energy QCT gave similar results, indicating little change in trabecular fat content. A significant correlation was demonstrated between mean serum oestradiol levels during treatment with nafarelin and the change in bone mineral (r = 0.655, P less than 0.005).