Does vitamin D₃ dosing schedule influence treatment efficacy in nursing home residents with vitamin D deficiency?

Abstract

Vitamin D deficiency is a common problem among elderly nursing home residents. In this Practice Point commentary, I discuss the findings and limitations of a randomized, controlled trial by Chel et al. that evaluated the effect of equivalent oral doses of vitamin D₃ given as 600 IU daily, 4,200 IU weekly or 18,000 IU monthly. Regardless of the dosing schedule, oral administration of vitamin D₃ was associated with increased levels of serum 25-hydroxyvitamin D and reduced levels of parathyroid hormone in the study cohort. Daily administration of vitamin D₃ was found to be more effective than either weekly or monthly administration. The addition of calcium supplementation for a 2-week period did not appreciably augment the effects of vitamin D₃ supplementation. Here, I highlight the issues to consider when interpreting studies of vitamin D₃ supplementation, its effect on vitamin D status, and the consequences for calcium and bone metabolism.