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Clinical Practice Assessment Screening for Vitamin D Deficiency Clinical Question: In what clinical setting is screening for 25- OH Vitamin D deficiency useful? Bottom Line: Screening for Vitamin D deficiency is not recommended. Measuring 25-OH Vitamin D levels is only necessary in the evaluation of suspected disorders of calcium regulation or metabolic bone disease. In other patients supplementation with Vitamin D at a dose of 1000 IU daily can be offered without a need for measuring 25-OH Vitamin D levels. The risk of hypercalcaemia with supplementation at this level is insignificant. Synopsis: Recently many widespread health benefits have been associated with Vitamin D supplementation. Profound deficiency causes osteomalacia with the associated clinical findings of deep proximal bone pain, weakness and fractures. Meta-analysis studies have shown Vit D supplementation of 400-7001000 IU reduces the incidence of falls and mortality. Similar Vitamin D doses with calcium supplementation reduces fracture incidence. Less certain associations with Vitamin D include decreased risks of cardiovascular disease, diabetes and even cancer. It remains unclear as to the association of other clinic finding to Vitamin D deficiency or the benefits of treatment beyond that of 1000 IU per day. There is no accepted or recommended reason for measuring 25-OH Vitamin D based on clinical symptoms. Vitamin D deficiency (measured by serum 25-OH Vitamin D levels) leads to secondary hyperparathyroidism and bone loss. Vitamin D supplementation has been shown to decrease plasma levels of parathyroid hormone (PTH), to temper the elevations of bone turnover markers and increase bone mineral density. The 25-OH Vitamin D level needed to prevent secondary hyperparathyroidism has been estimated to be between 10ng/ml to 50ng/ml and is generally accepted above 20ng/ml. In those with osteoporosis, supplementation of Vitamin D with calciferol should be given if a 25-OH Vit D level < 20ng/ml with a goal of maintaining the level above 32ng/ml. One can expect a 20ng/ml level to increase to 32ng/ml with 1700 IU of Vitamin D a day. Conditions associated with low Vitamin D levels include: malabsorption, osteoporosis, chronic renal disease, drugs including phenytoin, phenobarbitol, carbamazepine, isoniazide, theophyline, rifampin, antiretroviral agents and glucocorticoids. In evaluating patients with disorders of calcium regulation, osteoporosis (meaning a high fragility fracture risk) or those who on bone density have a Z-score of < -2.0, measuring a 25-OH Vitamin D levels is indicated. Vitamin D deficiency with secondary hyperparathyroidism is common and replacement along with a total calcium intake of 1000-1200mg/day total lowers the incidence of future fractures. Unless the history or exam suggests the possibility of other medical issues being present the evaluation for causes of osteoporosis beyond a 25-OH Vitamin D level needs to only include a complete chemistry panel, TSH, PTH and a 24-hour urine for calcium. Treatment options; Forms of inactive Vitamin D (calciferol): o Cholecalciferol Vitamin D3 synthesized in the skin by sunlight UVB o Erogocalciferol Vit D2 present in plants and some fish o Vitamin D3 may be up to 3x more potent than Vit D2 o Available strengths of Vitamin D3 include 400, 1000, 2000, 5000 and 50,000 IU tabs Effectiveness of Vitamin D supplementation: o 1000 IU=25ug of Vitamin D which typically increases the serum 25-OH level by 7 ng/ml o 25-OHD ng/ml x 2.50 converts to nmol/l. 20ng/ml=50nmol/l Sources; 1. Bjorkman M. Responses of PTH to Vitamin D supplementation: A systemic review of clinical trials. Arch Geront Geriat 2009; 48:160. 2. Semba RD. Relationship of 25-OHD with all-cause and CV disease mortality in older communitydwelling adults. Europ J Clin Nut 2009; doi:10.1038/ejcn.2009.140. 3. Bischoff-Ferrare H. Vit D: What is an adequate Vit D level and how much supplementation is necessary. Best Pract Resear Clin Rheum 2009; 23:789. 4. Kanekar A. Vit D deficiency: A clinical spectrum: Is there a symptomatic nonosteomalacic state? Int J of Endoc 2010. doi:10.1155/2010/521457. 5. Kulie T. Vit d: An evidence-based review. JABFM 2009; 22: 698. 6. Plotnikoff GA. Prevalence of severe hypovitaminosis D in patients with persistent, nonspecific musculoskeletal pain. Mayo Clin Proc 2003; 78:1463. 7. Bjorkman M. Vit D supplementation has no major effect on pain or pain behavior in bedridden geriatric patients with advanced dementia. Aging Clin Exp Res 2008; 20:316. 8. Bischoff-Ferrari HA. Prevention of nonvertebral fractures with oral vitamin D and dose dependency: a meta-analysis of randomized controlled trials. Arch Intern Med. 2009 Mar 23; 169(6):551-61. 9. Bischoff-Ferrari HA. Fall prevention with supplemental and active forms of vitamin D: a metaanalysis of randomized controlled trials. BMJ. 2009 Oct 1; 339:b3692. doi: 10.1136/bmj.b3692. 10. Autier P. Vitamin D supplementation and total mortality: a meta-analysis of randomized controlled trials. Arch Intern Med. 2007; 10:1709-10. 11. Abrahamsen B. Patient level pooled analysis of 68,500 patients from seven major vitamin D fractures trails in US and Europe. BMJ 2010; 340:5463. Originated: 4/20/11