Vitamin D and kidney stone disease.

PURPOSE OF REVIEW: Vitamin D is important in maintaining calcium homeostasis, but its role in kidney stone disease and its effect on stone formation are still not clear. RECENT
FINDINGS: Kidney stone formers tend to experience enhanced intestinal calcium absorption, increased urinary calcium excretion, and excessive bone mineral loss. Although direct actions of active vitamin D have been implicated in all these processes, the effect of nutritional vitamin D (vitamin D2 or vitamin D3) use on calcium balance among stone formers is still not clear. In addition, the safety of nutritional vitamin D use in the stone forming population is also not established, considering the potential effect of its use on raising urinary calcium. However, most of the observational studies do not support a significant association between higher nutritional vitamin D store and increased risk of stone formation. Short-term nutritional vitamin D repletion in stone formers with vitamin D deficiency also does not appear to increase urinary calcium excretion.
SUMMARY: The effect of nutritional vitamin D use in stone formers is still not clear. As vitamin D deficiency is highly prevalent among stone formers, future prospective studies are needed to establish the biological effect, as well as the safety and efficacy of nutritional vitamin D therapy in this unique patient population.