vitamin d deficiency

Vitamin D deficiency, or hypovitaminosis D is defined as a vitamin D level that is below normal. It most commonly occurs in people when they have inadequate sunlight exposure (in particular sunlight with adequate ultraviolet B rays (UVB). Vitamin D deficiency can also be caused by inadequate nutritional intake of vitamin D, disorders limiting vitamin D absorption, and conditions impairing vitamin D conversion into active metabolites—including certain liver, kidney, and hereditary disorders. Deficiency ...