Association of vitamin D receptor gene polymorphism with the occurrence of low bone density, osteopenia, and osteoporosis in patients with type 2 diabetes

Purpose This study aims to analyze the association between VDR gene polymorphism and the occurrence of "low bone density (LBD)/osteopenia/osteoporosis" or LBDOO in type 2 diabetes (T2D) patients among a clustered population in northwest of Iran. The studied VDR gene polymorphism included ApaI (rs7975232), BsmI (rs1544410), FokI (rs2228570), EcoRV (rs4516035) and, TaqI (rs731236). Methods In this population-based cross-sectional study, patients with T2D were identified within a group of 1266 participants based on self-report of diabetes, history of diabetes medication, and recorded laboratory data. Separately for each polymorphism and gender, crude and adjusted (age, BMI) odds ratios (ORs) were calculated for participants with T2D through logistic regression analysis. Results The prevalence of T2D was 16.41% in people residing in the city of Sanandaj in 2011. Of the participants with T2D, 13.92% and 81.29% had osteoporosis and vitamin D deficiency, respectively. In women, the tt genotype of the TaqI gene significantly decreased the risk of LBDOO versus the Tt genotype, after adjusting for BMI and age (adjusted OR:0.18, CI95%: 0.03-0.97). Conversely, the EE genotype of the EcoRV gene enhanced the risk of LBDOO versus the Ee genotype (adjusted OR:7.64, CI95%: 2.03-28.72). Conclusion The polymorphism of both TaqI and EcoRV genes was associated with the risk of LBDOO in women with T2D. This is the first time a study has highlighted this effect for the polymorphism of the EcoRV gene; we believe that this study would serve as a basis for future studies.