Effect of the Vitamin D Receptor Polymorphism on Bone Mineral Density and Bone Metabolism

Introduction: Vitamin D Receptor (VDR) polymorphisms are known to affect some aspects of bone metabolism, but the manifestations in a vitamin D deficient population are not that well known. Aim: To assess the effect of VDR polymorphisms on Bone Mineral Density (BMD) and biochemical manifestations of vitamin D deficiency in a vitamin D deficient population. Materials and Methods: Thirty participants with vitamin D deficiency {25 (OH)D=<20 ng/mL} and other biochemical features of vitamin D deficiency, i.e., elevated serum ALP, plasma PTH or decreased serum phosphate, were recruited as cases. Thirty participants with vitamin D deficiency (<20 ng/mL) who had no biochemical features of vitamin D deficiency were recruited as controls. Biochemical investigations and BMD were measured in all participants. VDR polymorphism (Fok1 and Bsm1) were analysed with Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) analysis. ChiSquare, Analysis of variance (ANOVA) and Multivariate Analysis Of Variance (MANOVA) are used as statistical analysis. Results: Genotype frequency of Bsm1 and Fok1 were similar among cases and controls. BMD at L3 vertebra (lumbar spine lateral) was higher in Ff genotype of Fok1, whereas BMD at lumbar spine (L4 vertebra) was lower in bb genotype of Bsm1. In multivariate analysis BMD at lumbar spine, was affected by genotype of Bsm1 (Bb). Body Mass Index (BMI) was higher among participants with BB in comparison to bb genotype. Conclusion: An association was found between BMD, BMI and VDR polymorphisms. However, distribution of different VDR polymorphisms was similar among participants who had and who did not have subtle manifestations of vitamin D deficiency.