Vitamin D refers to a group of fat-soluble secosteroids. Their receptors are found in nearly every tissue and impacts multiple biological processes. In humans the most important of the group are vitamin D3 (cholecalciferol) and D2 (ergocalciferol). Few foods contain vitamin D and the major natural source is synthesis from cholesterol in skin though a chemical mechanism that requires sunlight (specifically UVB radiation). It appears that as many as 70% of American children have inadequate vitamin D levels (25-hydroxyvitamin D; 25(OH)D).
A prospective case-controlled study of 60 urban children (aged 2-14 years) with fractures requiring conscious sedation/general anesthesia compared their 25(OH)D levels to a comparable non-fractured group.