The effect of 1alpha-hydroxyvitamin D3 with and without oestrogens on calcium balance in post-menopausal women.

Balance studies were performed in thirty-three post-menopausal women (all but five having vertebral crush fractures or femoral neck fractures) in the basal state and on treatment with 1alpha-hydroxyvitamin D3 and/or oestrogenic hormones. The results suggest that the effectiveness of oestrogen therapy is limited by calcium malabsorption and the effectiveness of 1alpha-hydroxyvitamin D3 is limited by oestrogen deficiency. The best results were obtained with combined therapy to remedy what appears to be two distinct deficiencies. To minimize the risks of hypercalcaemia and the possible risks of hormone therapy, we suggest that the treatment of choice in post-menopausal osteoporosis may be 1alpha-hydroxyvitamin D3 1microgram daily and ethinyloestrodiol 25 microgram daily for 3 weeks in every 4. Patients on a low dietary intake of calcium should probably be given calcium supplements. With this regimen, it should not be necessary to screen patients initially for calcium malabsorption or oestrogen deficiency because the majority of patients present with a combination of the two factors.