Vitamin D as a drug.

Vitamin D has an important role in bone-metabolism (and its deficiency can cause preterm osteopenia, craniotabe and rickets), but it has also non-calcitropic functions. In fact, vitamin D deficiency is correlated to chronic kidney disease, respiratory infections, type 1 diabetes, psoriasis, Crohn disease and neonatal hypocalcemia. Because of the vitamin D deficiency is a global problem, its role as a drug is fundamental for the human health in all ages.