Endocrine Abstracts

Introduction: Prevalence of vitamin D deficiency is relatively high worldwide, it is associated with poor skeletal health and has recently been related to other extra-skeletal diseases, probably due to its immunomodulatory effects. Detection and treatment of asymptomatic hypovitaminosis D in healthy adult population is especially relevant to attempt to optimize the overall functioning of the human body.

Objectives: To assess the percentage of adult healthy population with vitamin D deficiency (25(OH)D < 20 ng/ml) who achieved plasmatic levels within optimal range (20-60 ng/ml) after a four-month treatment with calcifediol 0.266 mg soft capsules, with monthly or biweekly treatment schedules.

Methods: Multicentre, phase I clinical trial. Volunteers (18-55 years) with vitamin D deficiency were assigned to receive calcifediol 0.266 mg for 4 months according to baseline levels: severe deficiency (25(OH)D < 10 ng/ml) was supplemented biweekly, while mild-moderate deficiency (25(OH)D 10-19.99 ng/ml) was treated monthly. Subsequently, subjects within the optimal range were randomly allocated to monthly treatment (placebo or calcifediol 0.266 mg), for 5 additional months.

Results: 79 subjects (65% female, mean age 31.2 years) are included in this analysis; 9% with severe vitamin D deficiency and 91% with mild-moderate vitamin D deficiency. Average baseline 25(OH)D levels (14.02 ng/ml; n=77, 2 subjects excluded due to protocol deviations), increased up to 20.53 ng/ml and to 27.56 ng/ml at months 1 and 4. In the biweekly treatment group, 25(OH)D levels increased by 17.05 ng/ml (month 1) and 33.05 ng/ml (month 4), whereas with monthly treatment 25(OH)D levels increased by 5.78 ng/ml and 12.18 ng/ml, respectively. 79% of subjects achieved optimal 25(OH)D levels at month 4 (100% in the biweekly group, 78% with the monthly treatment). The analysed bone metabolism parameters in all subjects (calcium, PTH, albumin, phosphate, alkaline phosphatase) showed no significant changes throughout the study. Calcium and PTH baseline levels were 9.38 ± 0.40 mg/dL and 51.36 ± 18.53 pg/ml, remaining unaltered at month 4 (9.57 ± 0.40 mg/dL and 50.40 ± 22.38 pg/ml, respectively). In terms of safety, no patient reached 25(OH)D toxic levels. No serious adverse events were reported.

Conclusions: Monthly calcifediol 0.266 mg is an effective and safe treatment for vitamin D deficiency in the overall population. Moreover, and bearing in mind the sample size limitations, biweekly calcifediol 0.266 mg showed to be a safe and effective treatment for vitamin D severe deficiency in the target population and without clinically relevant variation in bone metabolism parameters.