Vitamin D and Glucose Metabolism in Pediatrics

Summary

The discovery that the vitamin D receptor is expressed in more than 30 tissues indicates that the physiologic functions of vitamin D are much broader than its well-known role in the regulation of calcium absorption and bone metabolism. There is evidence that vitamin D is involved in the pathogenesis of cancer, cardiovascular disease, multiple sclerosis, and type I diabetes. Recent epidemiological evidence points to a strong association between vitamin D insufficiency and insulin resistance, the metabolic syndrome, and type II diabetes. The investigators would like to examine the role of vitamin D in the development of insulin resistance in overweight children and adolescents, which represent a high risk population for cardiovascular and metabolic complications. The investigators propose a prospective randomized clinical trial of vitamin D supplementation in overweight, insulin resistant, vitamin D deficient children. The investigators objective is to assess if changes in insulin resistance, fasting lipid profiles, blood pressure, and inflammatory markers occur in these patients post treatment with vitamin D. Additionally, concomitant changes in calcium and bone metabolism after vitamin D treatment will be evaluated. This is because, contrary to adults, the optimal vitamin D concentrations that regulate calcium and bone metabolism have not been established in pediatrics.

Timeline

Start

2011-04

Primary completion

2012-03

Completion

2012-03

Publications

• Background Alemzadeh R, Kichler J, Babar G, Calhoun M. Hypovitaminosis D in obese children and adolescents: relationship with adiposity, insulin sensitivity, ethnicity, and season. Metabolism. 2008 Feb;57(2):183-91. doi: 10.1016/j.metabol.2007.08.023.
• Background Holick MF. Vitamin D deficiency. N Engl J Med. 2007 Jul 19;357(3):266-81. doi: 10.1056/NEJMra070553. No abstract available.
• Background Chiu KC, Chu A, Go VL, Saad MF. Hypovitaminosis D is associated with insulin resistance and beta cell dysfunction. Am J Clin Nutr. 2004 May;79(5):820-5. doi: 10.1093/ajcn/79.5.820.
• Background Smotkin-Tangorra M, Purushothaman R, Gupta A, Nejati G, Anhalt H, Ten S. Prevalence of vitamin D insufficiency in obese children and adolescents. J Pediatr Endocrinol Metab. 2007 Jul;20(7):817-23. doi: 10.1515/jpem.2007.20.7.817.
• Background Munns C, Zacharin MR, Rodda CP, Batch JA, Morley R, Cranswick NE, Craig ME, Cutfield WS, Hofman PL, Taylor BJ, Grover SR, Pasco JA, Burgner D, Cowell CT; Paediatric Endocrine Group; Paediatric Bone Australasia. Prevention and treatment of infant and childhood vitamin D deficiency in Australia and New Zealand: a consensus statement. Med J Aust. 2006 Sep 4;185(5):268-72. doi: 10.5694/j.1326-5377.2006.tb00558.x.
• Background Keskin M, Kurtoglu S, Kendirci M, Atabek ME, Yazici C. Homeostasis model assessment is more reliable than the fasting glucose/insulin ratio and quantitative insulin sensitivity check index for assessing insulin resistance among obese children and adolescents. Pediatrics. 2005 Apr;115(4):e500-3. doi: 10.1542/peds.2004-1921. Epub 2005 Mar 1.
• Background Katz A, Nambi SS, Mather K, Baron AD, Follmann DA, Sullivan G, Quon MJ. Quantitative insulin sensitivity check index: a simple, accurate method for assessing insulin sensitivity in humans. J Clin Endocrinol Metab. 2000 Jul;85(7):2402-10. doi: 10.1210/jcem.85.7.6661.
• Background Matsuda M, DeFronzo RA. Insulin sensitivity indices obtained from oral glucose tolerance testing: comparison with the euglycemic insulin clamp. Diabetes Care. 1999 Sep;22(9):1462-70. doi: 10.2337/diacare.22.9.1462.
• Background Radikova Z, Koska J, Huckova M, Ksinantova L, Imrich R, Vigas M, Trnovec T, Langer P, Sebokova E, Klimes I. Insulin sensitivity indices: a proposal of cut-off points for simple identification of insulin-resistant subjects. Exp Clin Endocrinol Diabetes. 2006 May;114(5):249-56. doi: 10.1055/s-2006-924233.
• Background Pittas AG, Lau J, Hu FB, Dawson-Hughes B. The role of vitamin D and calcium in type 2 diabetes. A systematic review and meta-analysis. J Clin Endocrinol Metab. 2007 Jun;92(6):2017-29. doi: 10.1210/jc.2007-0298. Epub 2007 Mar 27.
• Background Palomer X, Gonzalez-Clemente JM, Blanco-Vaca F, Mauricio D. Role of vitamin D in the pathogenesis of type 2 diabetes mellitus. Diabetes Obes Metab. 2008 Mar;10(3):185-97. doi: 10.1111/j.1463-1326.2007.00710.x.
• Background Forouhi NG, Luan J, Cooper A, Boucher BJ, Wareham NJ. Baseline serum 25-hydroxy vitamin d is predictive of future glycemic status and insulin resistance: the Medical Research Council Ely Prospective Study 1990-2000. Diabetes. 2008 Oct;57(10):2619-25. doi: 10.2337/db08-0593. Epub 2008 Jun 30.

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