Introduction to the third annual rostand vitamin D symposium.

The role of vitamin D in multiple organ systems has come into sharp focus with recent advances in the understanding of its mechanisms of actions and specific effects of vitamin D preparations that serve as substrates and those that directly activate the vitamin D receptor. Major progress has been made in understanding the interplay between the vitamin D system and the FGF23/Klotho system for regulation of renal phosphate excretion. While recognizing the importance of treating secondary hyperparathyroidism in chronic kidney disease, the current interests have moved beyond this indication and are focusing on the role of vitamin D receptor and its activators in the basic pathophysiology of hypertension, cardiovascular disease, kidney disease, and overall patient outcomes.