Insufficient circulating levels of vitamin D is a common problem in both developed and developing countries; it is estimated that over one billion people have vitamin D deficiency at this time. In children, vitamin D deficiency leads to nutritional rickets, which is considered the most common non-communicable disease of children worldwide. Rickets causes significant short term morbidity and mortality through hypocalcemic tetany and seizures, as well as long term morbidity from growth delay and skeletal deformities. Recent data also suggest that children who have had nutritional rickets are three times more likely to develop type 1 diabetes.