Efficacy and safety of doxercalciferol (1α hydroxyvitamin D

Background: The use of small doses of vitamin D Methods: In a 1-year pilot randomized double-blind, placebo-controlled study, 55 postmenopausal women (aged 60-71 years) with osteopenia were treated for a year with either doxercalciferol or placebo, and 41 women completed an optional second year. The dose of 1 µg was increased by 1 µg at weekly intervals to a maximum of 5 µg. The daily dose of doxercalciferol averaged 4.1 µg after 12 months and 3.6 µg after 24 months. Bone mineral density (BMD) measurements by dual-energy X-ray absorptiometry (DEXA) of the spine and femoral neck were obtained at 6-month intervals for 24 months. The serum and urine calcium levels were measured frequently for safety. Results: In the primary intention-to-treat (ITT) analysis at 12 months, there was no significant difference between the two groups for femoral neck and spine BMD. At 24 months, there was a significant difference in favor of doxercalciferol for femoral neck BMD, with the treatment/placebo difference being 1.70% ( Conclusions: The results show that doxercalciferol treatment showed no difference from the placebo group on bone loss at 12 months; however, at 24 months, doxercalciferol showed significant prevention of bone loss from the femoral neck and spine. Clinical Trial Registration: https://clinicaltrials.gov/, identifier NCT07660536.