The VDR rs1544410 and rs11568820 Variants and the Risk of Osteoporosis in the Polish Population.

Vitamin D affects bone metabolism and calcium-phosphate metabolism. Its deficiency leads to bone mineralization disorders and is the cause of abnormal skeletal development from fetal life to the period of completed skeletal growth. In later periods of life, vitamin D deficiency leads to bone metabolism disorders, i.e., osteoporosis. Disturbance of the balance between osteoblasts responsible for bone formation and osteoclasts associated with bone resorption results in reduced bone mass and bone weakening, and consequently leads to susceptibility to fractures. Analysis of genetic variants of the vitamin D receptor ( VDR ) concerns their relationship with metabolic bone diseases, and the results of previous studies assessing the relationship of polymorphisms with bone mineral density, fracture risk, or osteoporosis are not clear. Therefore, the aim of our study was to determine the effect of rs1544410 and rs11568820 polymorphisms of the VDR gene on the risk of developing osteoporosis in the Polish population. The study included 197 women with osteoporosis, 98 women with osteopenia, and 147 healthy controls. The real-time PCR method was used to determine the rs1544410 and rs11568820 polymorphisms of the VDR1 gene. Analysis of the results in the group with osteopenia showed that for the rs1544410 polymorphism, heterozygous GA genotypes occurred in 37.8% of the study group and 47.6% of the controls (OR = 0.60; 95%CI: 0.34-1.05), and homozygous AA in 15.3% of the study group and 17.0% of the controls (OR = 0.68; 95%CI: 0.32-1.44) ( p = 0.185, AIC = 332.4; AIC-Akaike information criterion). The best model for this variant turned out to be the dominant model OR = 0.62; 95%CI: 0.37-1.04; p = 0.071, AIC = 330.5. In the case of the rs11568820 polymorphism of the VDR gene, the GG genotype was more common in women with osteopenia compared to controls (75.5% vs. 70.1%). Genotypes containing at least one mutant A allele were present in 24.5% of women with osteopenia and 29.9% of controls (OR = 0.76; 95%CI: 0.43-1.36; p = 0.349; AIC = 332.9). Analyzing the rs1544410 polymorphism in women with osteoporosis, the GA genotype was present in 42.1% of the study group and 47.6% of patients with normal bone density (OR = 0.74; 95%CI: 0.46-1.19), and the AA genotype in 15.7% of the study group and 17.0% of controls (OR = 0.78; 95%CI: 0.41-1.46) ( p = 0.441). In the case of the rs11568820 polymorphism, the GA genotype occurred in 22.3% of the study subjects and 27.2% of the control patients (OR = 0.76; 95%CI: 0.46-1.25), and the AA genotype in 2.0% of the study subjects and 2.7% of the controls (OR = 0.69; 95%CI: 0.17-2.83) ( p = 0.511). For both variants, the model with the lowest AIC value was the dominant model, in which for the rs1544410 variant OR = 0.75; 95%CI: 0.48-1.17; p = 0.203; AIC = 472.0 was obtained, while for rs11568820-OR = 0.75; 95%CI: 0.47-1.22; p = 0.250; AIC = 472.3. The obtained results indicate that the rs1544410 and rs11568820 polymorphisms of the VDR gene do not affect the development of osteoporosis in the Polish population.