Association of Vitamin D Receptor (VDR) Gene Polymorphisms with Osteoporotic Vertebral Fracture Risk: A Case–Control Study

Background/Objectives: Osteoporosis is a systemic skeletal disorder characterized by reduced bone mass and microarchitectural deterioration, resulting in an increased risk of fragility fractures, particularly vertebral fractures. Genetic factors are considered important in osteoporotic fracture susceptibility, and polymorphisms of the vitamin D receptor (VDR) gene have been widely studied because of their role in bone metabolism. To evaluate the distribution of VDR gene polymorphisms (FokI, BsmI, ApaI, and TaqI) in patients with osteoporotic vertebral fractures and to assess their association with fracture susceptibility. Methods: This case–control study included 86 individuals: 43 patients who underwent vertebroplasty for osteoporotic vertebral fractures and 43 osteoporotic individuals without vertebral fractures serving as controls. VDR gene polymorphisms ApaI, TaqI, BsmI and FokI were analyzed using real-time polymerase chain reaction. Genotype distributions were compared using Fisher’s exact test, and Hardy–Weinberg equilibrium was evaluated. Results: A significant difference between groups was observed only for the ApaI polymorphism (p = 0.002). The GG genotype was more frequent in patients, whereas the variant genotypes (GT and TT) were more prevalent in controls. The GG genotype was associated with an increased risk of vertebral fractures, while the presence of variant genotypes may be associated with reduced fracture susceptibility. No significant associations were found for TaqI, BsmI, or FokI polymorphisms. Conclusions: The ApaI polymorphism of the VDR gene may represent a protective genetic factor against osteoporotic vertebral fractures. In contrast, no associations were identified for the TaqI, BsmI, or FokI polymorphisms in this cohort. Larger studies in diverse populations are required to confirm these findings and to clarify the role of VDR gene variants in fracture susceptibility.