Vitamin D status and vitamin D receptor gene polymorphisms and susceptibility to type 1 diabetes in Egyptian children

Background: Type 1 diabetes mellitus (TI DM) is recognized as a T-cell-mediated autoimmune disease. Vitamin D compounds are known to suppress T-cell activation by binding to vitamin D receptor (VDR); and thus, VDR gene polymorphisms may be related to T-cell-mediated autoimmune diseases. The aim of this study was to investigate the association between vitamin D status and VDR gene polymorphisms and T1DM. Materials and methods: One hundred and twenty patients with TI DM and one hundred and twenty controls were enrolled in the study. VDR gene Bsml, Fokl, Apal and Taql polymorphisms were determined using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). Serum 25-hydroxyvitamin D (25(OH)D) was determined using ELISA. Result: Serum 25( OH)D levels revealed a vitamin D deficiency or insufficiency in 75% of the patients. The mean levels of vitamin D were significantly lower in patients as compared to their controls (P = <0.001). VDR Bsml Bb and bb genotypes and VDR FokI Ff and if genotypes were associated with increased risk of T1 DM (OR = 2.3, 95% CI = 1.3-4.2, P = 0.005; OR = 2.2, 95% CI = 1.1-4.7, P = 0.04; OR = 1.8, 95% CI = 1.033.04, P = 0.04; OR = 4.03, 95% CI = 1.2-13.1, P = 0.01 respectively), while the VDR ApaI and TagI polymorphisms were not. Conclusion: Our study indicated that vitamin D deficiency and VDR Bsml and Fokl polymorphisms were associated with T1DM in Egyptian children. (C) 2013 Elsevier B.V. All rights reserved.