Introduction to Vitamin D Symposium, March 14, 2008.

A large body of work in diverse clinical and scientific areas has accumulated that supports a role for vitamin D in multiple organ systems and physiologic and molecular processes. The vitamin D receptor is distributed ubiquitously, and by binding with its receptor, vitamin D initiates a series of events that can affect cellular proliferation and differentiation, inflammation, the immune system, and the endocrine system, including the renin-angiotensin system, insulin resistance, and lipid metabolism.