[Vitamin D deficiency in adults: to better understand a new presentation of an old disease].
Vitamin D is synthesized in skin through a reaction mediated by sunlight, and it is metabolized to 25-hydroxyvitamin D, in liver, and in 1,25-dihydroxyvitamin D, in kidney. This last reaction has a tight feedback mechanism. 1,25-dihydroxyvitamin D is the active hormone, and its actions are mediated mainly by nuclear receptors. Its major functions are in calcium metabolism and bone mass maintenance. Hypovitaminosis D, as a disease in adult people, manifests itself with hypocalcemia and secondary hyperparathyroidism with subsequent loss of trabecular bone, thinning of cortical bone, and, eventually, a higher risk of fractures. Hypovitaminosis D is a very common condition in Europe, Africa, North America and some South American countries, such as Chile and Argentina. Measurement of serum total 25-hydroxyvitamin D concentration is the gold standard to diagnose vitamin D deficiency. Serum concentrations below 50 nmol/L are associated with an increase in parathyroid hormone concentration, and bone loss. Risk factors for vitamin D deficiency, like poor sunlight exposition, aging skin and factors that interfere with normal vitamin D metabolism, are well established. Oral vitamin D supplementation, an easy and inexpensive treatment, is needed to treat this illness.
Premaor
Melissa Orlandin
MO
Departamento de Medicina Interna, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS.
Furlanetto
Tania Weber
TW
D000328:Adult; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000209:etiology; D006996:Hypocalcemia / Q000209:etiology; D010024:Osteoporosis / Q000209:etiology; D012307:Risk Factors; D012720:Severity of Illness Index; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000097:blood / Q000502:physiology*; D014808:Vitamin D Deficiency / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology; D014815:Vitamins / Q000008:administration & dosage
D014815:Vitamins; D014807:Vitamin D; C104450:25-hydroxyvitamin D