Early postmenopausal bone loss is not associated with a decrease in circulating levels of 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, or vitamin D-binding protein

To study changes in the rate of bone loss before and after the menopause, 19 normal premenopausal women of the same age were followed with annual measurements of appen-dicular bone mass for 8 yr. Their serum estrone, estradiol, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and vitamin D-binding protein levels also were measured annually. The serum estrogen levels declined before the menopause, and the rate of bone loss more than doubled at the time of the menopause. There were no significant changes in the serum 25-hydroxyvitamin D, 1,25-dihydroxyvitamin LD or vitamin D-binding protein levels from the pre- to the postmenopausal period. We conclude that changes in vitamin D metabolite levels are not associated with early postmenopausal bone loss.