Effects of combined low dose of the isoflavone derivative ipriflavone and estrogen replacement on bone mineral density and metabolism in postmenopausal women.

OBJECTIVES: To assess the pattern of biochemical markers of bone metabolism and vertebral bone mineral density in early postmenopausal women treated with combined ipriflavone and low dose conjugated estrogens. METHODS: Bone biochemical markers and vertebral bone density were evaluated in a longitudinal, comparative, 2 year study conducted in postmenopausal women treated with sole calcium supplementation (500 mg/day), or with either ipriflavone (IP) at the standard dose (600 mg/day) plus the same calcium dose, low dose conjugated estrogens (CE) (0.3 mg/day) plus calcium, or low dose IP (400 mg/day) plus low dose CE (0.3 mg/day) plus calcium. The results were analyzed by repeated measures analysis of variance, as appropriate. RESULTS: No modifications of both urinary excretion of hydroxyproline and plasma osteocalcin levels were observed in calcium and in CE-treated women, while vertebral bone density significantly decreased (P < 0.0001) in both groups. In IP or IP + CE-treated women, plasma osteocalcin did not show any modification, while urinary hydroxyproline showed a significant (P < 0.05) decrease, that paralleled a significant (P < 0.05) increase in vertebral bone density. CONCLUSION: Postmenopausal IP administration, at the standard dose of 600 mg/day, can prevent the increase in bone turnover and the decrease in bone density that follow ovarian failure. The same effect can be obtained with the combined administration of low dose (400 mg/day) IP with low dose (0.3 mg/day) CE.