title: Vitamin D deficiency: a worldwide problem with health consequences.
abstract: Vitamin D deficiency is now recognized as a pandemic. The major cause of vitamin D deficiency is the lack of appreciation that sun exposure in moderation is the major source of vitamin D for most humans. Very few foods naturally contain vitamin D, and foods that are fortified with vitamin D are often inadequate to satisfy either a child's or an adult's vitamin D requirement. Vitamin D deficiency causes rickets in children and will precipitate and exacerbate osteopenia, osteoporosis, and fractures in adults. Vitamin D deficiency has been associated with increased risk of common cancers, autoimmune diseases, hypertension, and infectious diseases. A circulating level of 25-hydroxyvitamin D of >75 nmol/L, or 30 ng/mL, is required to maximize vitamin D's beneficial effects for health. In the absence of adequate sun exposure, at least 800-1000 IU vitamin D3/d may be needed to achieve this in children and adults. Vitamin D2 may be equally effective for maintaining circulating concentrations of 25-hydroxyvitamin D when given in physiologic concentrations.
authors.affiliation: Department of Medicine, Boston University School of Medicine, 715 Albany Street, M-1013, Boston, MA 02118, USA. mfholick@bu.edu
authors.forename: Michael F
authors.initials: MF
authors.lastname: Holick
authors.forename: Tai C
authors.initials: TC
authors.lastname: Chen
mesh_terms: D001327:Autoimmune Diseases / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control; D015519:Bone Density / Q000187:drug effects; D050071:Bone Density Conservation Agents / Q000008:administration & dosage / Q000096:biosynthesis; D001842:Bone and Bones / Q000378:metabolism; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control; D005527:Food, Fortified; D014943:Global Health; D006801:Humans; D009369:Neoplasms / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control; D009751:Nutritional Requirements; D012279:Rickets / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control; D013472:Sunlight; D014807:Vitamin D / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000096:biosynthesis / Q000097:blood; D014808:Vitamin D Deficiency / Q000150:complications / Q000453:epidemiology* / Q000517:prevention & control*
chemical_list: D050071:Bone Density Conservation Agents; D014807:Vitamin D; C104450:25-hydroxyvitamin D