BACKGROUND & AIMS: Oral supplementation with vitamin D is recommended for older adults to maintain a sufficient 25-hydroxyvitamin D (25(OH)D) status throughout the year. While supplementation with vitamin Dor Dis most common, alternative treatment regimens exist which require further investigation with respect to increasing 25(OH)D concentration. We investigated the dose-response effects of supplementation with calcifediol compared to vitamin Dand assessed the dose which results in mean serum 25(OH)Dconcentrations between 75 and 100 nmol/L. 2 3 3 3
METHODS: This randomized, double-blind intervention study included men and women aged ≥65 years (n = 59). Participants received either 5, 10 or 15 μg calcifediol or 20 μg vitamin Dper day, for a period of 24 weeks. Blood samples were collected every four weeks to assess response profiles of vitamin D related metabolites; serum vitamin D, 25(OH)D, 1,25-dihydroxyvitamin D(1,25(OH)D) and 24,25-dihydroxyvitamin D(24,25(OH)D). Further, serum calcium, plasma parathyroid hormone, and urinary calcium were evaluated. 3 3 3 3 2 3 3 2 3
RESULTS: Supplementation with 20 μg vitamin Dincreased 25(OH)Dconcentrations towards 70 nmol/L within 16 weeks. Supplementation with 10 or 15 μg calcifediol increased 25(OH)Dlevels >75 nmol/L in 8 and 4 weeks, respectively. Steady state was achieved from week 12 onwards with serum 25(OH)Dlevels stabilizing between 84 and 89 nmol/L in the 10 μg calcifediol group. A significant association was observed between the changes in 25(OH)Dand 24,25(OH)D(R = 0.83, P < 0.01), but not between 25(OH)Dand 1,25(OH)D(R = 0.04, P = 0.18). No cases of hypercalcemia occurred in any treatment during the study period. 3 3 3 3 3 2 3 3 2 3 2 2
CONCLUSIONS: Calcifediol supplementation rapidly and safely elevates serum 25(OH)Dconcentrations to improve vitamin D status in older adults. A daily dose of 10 μg calcifediol allows serum 25(OH)Dconcentrations to be maintained between 75 and 100 nmol/L. 3 3
TRIAL REGISTRATION NUMBER: NCT01868945.
