Pharmacokinetic profile and effect on bone markers and muscle strength of two daily dosage regimens of calcifediol in osteopenic/osteoporotic postmenopausal women.

Background At present, although cholecalciferol represents the form of vitamin D of choice for the treatment of vitamin D deficiency, there is a growing interest in calcifediol. Aims This study aimed to evaluate the efficacy and the safety of two different daily doses of calcifediol. Methods Fifty osteopenic/osteoporotic women with serum levels of 25-hydroxyvitamin D (25OHD) between 10 and 20 ng/ml were randomized to a 6-month treatment with oral calcifediol 20 µg/day (n = 25) or oral calcifediol 30 µg/day (n = 25). In all, we measured the time course of the levels of 25OHD and other biochemical parameters. Moreover, we evaluated handgrip strength and serum levels of myostatin. Results The peak increase in 25OHD levels was reached after 90 days of treatment in group 1 (59.3 ng/ml) and after only 60 days in group 2 (72.3 ng/ml); thereafter in both groups, the levels of 25OHD showed a tendency towards stabilization. After 30 days, all the patients treated with 30 µg/day had values of 25OHD > 30 ng/ml. Handgrip strength showed a modest but progressive increase which reached the statistical significance in the 30 µg/day group. This latter group also presented a modest and non-significant decrease in serum levels of myostatin. Conclusions Calcifediol is able to rapidly normalize the vitamin D deficiency, and the 30 µg daily dosage could be suggested in those patients who need to rapidly reach optimal 25OHD levels. Moreover, the 6-month treatment with calcifediol at a dose of 30 µg results in a modest but significant increase in upper limb strength.