The noncalciotropic actions of vitamin D: recent clinical developments

PURPOSE OF REVIEW: This review summarizes recently described actions of 1,25-dihydroxyvitamin D beyond its function in calcium homeostasis and bone metabolism. RECENT FINDINGS: 1,25-Dihydroxyvitamin D stimulates the innate immune system, facilitating the clearance of infections such as tuberculosis. Hypovitaminosis D has been associated with several autoimmune disorders, various malignancies, and cardiovascular risk factors in a number of recent epidemiologic reports. Based on these observational reports, vitamin D and its analogues are being evaluated for the prevention and treatment of a variety of conditions, with early findings showing mixed results. SUMMARY: The broad tissue distribution of the 25-hydroxyvitamin D 1alpha-hydroxylase enzyme and the vitamin D receptor establish a role for 1,25-dihydroxyvitamin D in the pathophysiology of various disease states and provide new therapeutic targets for vitamin D and its analogues.