VDR and metabolic disease: In addition, due to the ubiquitous expression of vitamin D receptors (VDR) in nearly all tissues and cells, vitamin D (active form, 1,25-dihydroxyvitamin D), through interaction with VDR, exerts numerous pleiotropic extra-skeletal effects that play a role in immune responses, cardiovascular events, cancer, and metabolic diseases [11, 12].