Effects of High Doses of Cholecalciferol in Normal Subjects: A Randomized Double-Blinded, Placebo-Controlled Trial
What this study found
Cholecalciferol did not significantly change 24-hour urinary calcium excretion versus placebo, but it substantially increased circulating vitamin D metabolites. The primary endpoint, change in 24-hour urinary calcium excretion, showed no between-group difference (P = 0.891). In the active group, 25(OH) vitamin D increased 186% versus 14% in placebo (P < 0.001) and 1,25(OH)2 vitamin D increased 28% versus -8% in placebo (P < 0.001). FGF23 increased 10% in the cholecalciferol group (P = 0.018), but the between-group difference in FGF23 change was not significant (P = 0.457). The authors…
- Study & population
- Randomized, double-blind, placebo-controlled trial in healthy vitamin D-insufficient adults aged 18 years or older at Roskilde University Hospital in Denmark.
- Intervention
- The active arm received oral cholecalciferol 3000 IU daily, given as 3 tablets of vitamin D3, for 16 weeks.
- Key limitation
- Small sample size, with only 22 participants in the active arm and 16-week follow-up, limits precision and long-term interpretation.
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Open PDFOriginal abstract
Background Vitamin D repletion with high doses of vitamin D is often recommended to patients and healthy subjects. The safety, especially concerning changes in urinary calcium excretion is of great importance. Methods In a double-blinded, placebo-controlled study in 40 healthy volunteers, we examined the changes in mineral metabolism during supplementation with 3000 IU of oral cholecalciferol daily during 4 months. Results Both 25(OH)vitamin D and 1,25(OH)2vitamin D increased significantly in the active treated group as compared to the placebo group (186% versus 14% (P<0.001) and 28% versus – 8% (P<0.001)). No change was observed in urinary calcium excretion in the active group compared to the placebo group (P = 0.891). Fibroblast growth factor 23 increased significantly by 10% (P<0.018) in the active group. However, there was no difference in changes in FGF23 between treatment groups (P = 0.457). Conclusion High dose cholecalciferol significantly increases 25(OH)vitamin D and 1,25(OH)2vitamin D levels compared to placebo. No changes in urinary calcium excretion or other measured components of the mineral metabolism were found between groups. Trial Registration ClinicalTrials.gov NCT00952562.