Effect of 1,25-dihydroxy-vitamin D3 in itself or combined with hormone treatment in preventing postmenopausal osteoporosis.

Eighty-four normal women, 2.5--5 years after their natural menopause, participated in a controlled double-blind trial. The effect of various therapeutic regimens on postmenopausal bone mineral loss was measured by photonabsorptiometric determination of the bone mineral content of both forearms. The women were randomized into four treatment groups: 1,25-dihydroxycholecalciferol (1,25(OH)2D3) alone in a daily dose of 0.25 micrograms, oestrogens/gestagen alone or combined with 1,25(OH)2D3, and placebo. The groups treated with oestrogens/gestagen (without and with 1,25(OH)2D3) showed a similar increase in bone mineral content of about 1% during one year of treatment. In contrast, both the placebo group and the 1,25(OH)2D3 group demonstrated a decrease of 1.9% and 2.1%, respectively, within the same period of time. While 1,25(OH)2D3 did not alter the rate of bone loss, it caused the characteristic and pronounced increase in urinary calcium excretion (15%). It is concluded that 1,25 (OH)2D3 neither serves as an alternative nor as an additive to gonadal hormones in the prevention of postmenopausal osteoporosis.