VDR gene polymorphisms rs731236 and rsS2228570 affect vitamin D levels in people of the Kaliningrad region

Vitamin D is an essential micronutrient that is involved in numerous biological processes. It not only keeps bones healthy, but also has a protective effect on the cardiovascular system, the pancreas and fatty tissue. Around 50% of the world’s population suffers from vitamin D deficiency or insufficiency. The prevalence of these diseases is significantly higher in obese people, regardless of age and place of residence. The presence of polymorphisms in the VDR gene (vitamin D receptor) can explain individual differences in the concentration of vitamin D 25(OH) in blood serum. Of particular interest are the effects of the polymorphisms rs731236 and rs2228570 on vitamin levels. Thus, the VDR polymorphism rs731236 is a synonymous substitution, whereas the polymorphism rs2228570 is a non-synonymous substitution. The article investigated the polymorphisms of the VDR gene rs2228570 (T/C), rs731236 (T/C) and determined their association with blood vitamin D levels in people from the Kaliningrad region with different body mass index (BMI). The material for the study was venous blood taken in the morning on an empty stomach from 232 people (mean age 50±13.5 years, 103 men and 129 women). The vitamin D content in the blood was determined by ELISA and the polymorphisms of the VDR gene were analyzed by PCR.

In individuals with a BMI > 30 kg/m², changes in the lipid profile and liver function tests were recorded. The vitamin D level did not depend on the BMI of the study participants. Significant changes in blood vitamin D levels were found depending on the distribution of the VDR genotype. Vitamin D levels were higher in individuals with the CC genotype than in the TT and CT genotypes of the rs2228570 polymorphism and did not depend on BMI. In contrast, the presence of the rs731236 polymorphism in the VDR gene is associated with BMI. In obesity, vitamin D levels are therefore only reduced in people with the TT genotype of the rs731236 polymorphism, but not in people with the CC and TC genotype.