Controlled randomized open label clinical study comparing the safety and efficacy of loading schedules in vitamin D...

Rapidly restoring vitamin D levels to normal might be desirable in certain clinical situations. Larger doses of supplementation, have been shown to increase bone loss and the risk of falls. The optimal way to perform vitamin D loading safely and effectively is still not well elucidated. Our study was aimed to assess the safety and efficacy of two oral vitamin D loading protocols. Sixty-nine subjects with vitamin D deficiency (25OH-vitamin D (25(OH)D) < 20 ng/ml) were included. Thirty-five participants received 30 000 IU of vitamin D₃ per week for 10 weeks (group Slower Loading Dose (SLD)) and thirty-four received 30 000 IU twice weekly for 5 weeks (group Moderate Loading Dose (MLD)) resulting in a loading dose of 300 000 IU for all subjects. Following this initial loading phase, both groups received 30 000 IU biweekly for 4 weeks to test whether the recommended daily vitamin D supplementation in range of 2000 IU dose-equivalent could maintain the achieved levels. Seventy-nine percent of those subjects treated in group SLD and everyone in group MLD achieved a 25(OH)D level of 30 ng/ml, which is the lower limit of the recommended normal range in Hungary. The mean increase in 25(OH)D was significantly higher in group MLD than in group SLD (38.6 ± 1.80 ng/ml vs 46,6 ± 1.80 ng/ml). No significant decrease was observed with the administration of the maintenance dose. There were no clinically significant changes in serum or urine calcium, and bone biomarkers in either group. Both protocols were found to be safe and effective, but the five-week dosing caused a significantly greater increase in 25(OH)D. A maintenance dose applied for four weeks after the loading protocol did not raise 25(OH)D levels further but maintained the achieved increase. The administration of 30 000 IU of vitamin D₃ twice weekly for five weeks is a rapid, effective and safe way to treat vitamin D deficiency in vitamin D deficient patients.