Hormone treatment related bone mineral content changes in Japanese women with endometriosis

The effects of a GnRH agonist and danazol on bone mineral content (BMC) in Japanese women with endometriosis were investigated. Nineteen women with laparoscopically confirmed endometriosis were treated with buserelin (900 micrograms/d administered intranasally, 10 cases) or with danazol (400 mg/d p.o., 9 cases) for 6 months. Trabecular BMC of the 3rd lumbar vertebra was measured using quantitative computerized tomography before treatment, at the end of treatment and 6 months after treatment by the same radiologist who was not informed about the drug used. Serum estradiol and the biochemical parameters of bone metabolism were also measured. A significant decrease in BMC (10% on average; maximum 25.4%) was observed at the end of treatment with buserelin (p < 0.01) and this loss was only partially recovered 6 months after treatment. In the danazol group, however, a slight gain in BMC was observed. Buserelin suppressed serum estrogen levels much more than danazol did. Parameters of bone resorption tended to increase in the buserelin group. Because treatment with buserelin, but not with danazol, was always associated with a significant decrease in BMC at L3, repeated usage of buserelin may lead to cumulative bone loss in patients with endometriosis.