Falls, Fractures Influenced By High-Dose Vitamin D?

High-dose vitamin D supplementation does not prevent falls and fractures in adults, a recent study showed.

The Vitamin D Assessment (ViDA) Study, a randomized, double-blind, placebo-controlled trial, recruited 5110 healthy adults aged 50 to 84 years from April 5, 2011, to November 6, 2012, in Auckland, New Zealand. Follow-up ended on July 31, 2015.
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Participants were randomly assigned to either an initial oral dose of 200,000 IU (5.0 mg) colecalciferol (vitamin D₃) followed by monthly 100,000 IU (2.5 mg) colecalciferol (n = 2558) or equivalent placebo dosing (n = 2552). Two participants who were randomly assigned to placebo withdrew from the trial.

Hazard ratios (HRs) were estimated using Cox proportional hazards models for time to first fracture or time to first fall in individuals receiving vitamin D compared with placebo. Fractures were analyzed via intention-to-treat, and falls were analyzed via questionnaires.

Demographic information indicated that the participants’ mean age was 65.9 years, and 58% of participants were men. Additionally, the mean concentration of 25(OH)D in the blood was 63 nmol/L at baseline, with 1534 patients having 25(OH)D concentrations lower than 50 nmol/L.

Mean treatment duration was 3.4 years. After follow-up, 2638 participants reported having a fall (1312 in the vitamin D group compared with 1326 in the placebo group). The researchers determined the HR for falls to be 0.99 for vitamin D vs placebo, after adjusting for age, sex, ethnic origin, history of recent fall, physical activity, and baseline 25(OH)D.

The researchers recorded non-vertebral fractures in 292 participants (156 in the vitamin D group compared with 136 in the placebo group). The adjusted HR for fractures was 1.19 for the vitamin D group compared with placebo.

“High-dose bolus vitamin D supplementation of 100,000 IU colecalciferol monthly over 2.5-4.2 years did not prevent falls or fractures in this healthy, ambulatory, adult population,” the researchers concluded. “Further research is needed to ascertain the effects of daily vitamin D dosing, with or without calcium.”

—Christina Vogt

Reference:

Khaw K-T, Stewart AW, Waayer D, et al. Effect of monthly high-dose vitamin D supplementation on falls and non-vertebral fractures: secondary and post-hoc outcomes from the randomised, double-blind, placebo-controlled ViDA trial. Diabetes Endocrinol. 2017;5(6):438-447. doi:10.1016/S2213-8587(17)30103-1.