الفهرس 
Vitamin DOnly 14 pages are availabe for public view
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Abstract
Vitamin D is a fat-soluble vitamin that is synthesized in the skin in response to sunlight exposure and is also obtained from dietary intake. Vitamin D is stored in adipose cells or is converted in the liver to its circulating form, 25(OH)D. Mainly in the kidneys, 25(OH)D is converted to its active metabolite, 1,25(OH)2D.1,25(OH)2D synthesis is enhanced by PTH and hypophosphatemia. Vitamin D deficiency is considered to be present if 25(OH) D level is less than 20 g/ mL. VDD is associated with rickets in children and osteomalacia in adults. Extra-skeletal manifestations of VDD are upper and lower respiratory tract infection, asthma, sepsis, DM, HTN, and cancer. Groups at risk of vitamin D inadequacy are breastfed infants, older adults, people with limited sun exposure, people with dark skin, those with fat mal-absorption and obese persons. Intensive Care Medicine is concerned with the provision of life support and body systems support in patients who require intensive monitoring as they are critically ill specially those whose condition is potentially reversible and with a good chance of survival with intensive care support of underlying condition that can be overcome. The prevalence of VDD in the critically ill adult is substantial in the range of 50%. VDD is associated with increased infection severity and cost in those admitted to adult ICUs. Observational data in critically ill cohorts support the concept that VDD can serve as a biomarker of illness severity and outcomes in critically ill patients and raise the issue of vitamin D as a potential therapeutic agent. VDD may be a major contributor to common morbidities seen among critically ill patients, including the SIRS, development and outcome of sepsis, MODS, and metabolic dysfunction.