The Effect of Supplementation With Two Different Doses of Vitamin D on Bone Mineral Density, Vitamin D Levels and Hand Grip Strength in Children With Diabetes Mellitus Type 1

Evidence indicates that majority (75-90%) of children with diabetes have lower serum concentrations of vitamin D, which may negatively impacts bone health and can be associated with reduction of muscular strength. There is still unknown what is the optimal dose of vitamin D in these patients for adequate supply of vitamin D throughout the year to assure optimal peak bone mass and muscle strengthThe aim of the study is to assess the effect of 12 month supplementation with two different doses of vitamin D ( 500 vs 1000) on bone mineral density, serum 25 hydroxyvitamin D levels and hand grip strength in preadolescents with diabetes mellitus type 1. 100 children in the of age 8 -11 with diabetes mellitus type 1 lasting for more than 3 months, without history of diabetic ketoacidosis during previous month, without other chronic disease which may affect calcium-phosphorus metabolism will be randomized in a double blind controlled trial to supplement them with either 500 IU or 1000 IU vitamin D. Every 3 months, in spring summer,autumn and winter serum level of calcium,25-hydroxyvitamin D level and HbA1c will be measured. At the entry and at the end of the study patients will have total body and lumbar spine bone mineral density assessment. Every six months hand grip strength will be measured. Additionally at the beginning and after 12 mo of supplementation and at the beginning serum levels of TNF-alfa, osteoprotegerin and IL-6 will be assessed.