Association of vitamin D receptor gene polymorphisms with metabolic syndrome: a case–control design of population-based cross-sectional study in North China

BACKGROUND: Metabolic syndrome (MS) increases a risk of developing cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM). The Vitamin D Receptor gene (VDR) may be important for developing MS. The aim of this study is to investigate the correlation between the VDR gene polymorphisms and MS in North China. METHODS: A case–control study included 391 participants with MS according to the MS diagnostic criteria of International Diabetes Federation 2005 (IDF2005) and 400 controls was conducted on the basis of a cross sectional study which was performed from 2008 to 2012 in Ningxia Hui Autonomous Region, China. Anthropometric data, blood pressure and blood samples were collected in the field investigation. Blood biochemistry analyses were carried out in the laboratory. Two single-nucleotide polymorphisms (SNPs) in the VDR gene, BsmI (rs1544410 A > G) and FokI (rs 2228570 C > T), were genotyped. RESULTS: The difference in the occurrence of genotypes in BsmI between individuals with MS and the control group was significant. Compared with genotype Bb/bb and allele b, genotype BB and allele B showed higher frequencies in MS cases than controls, which suggested they were risk factors. In addition, the genotype BB carriers with MS presented a higher waist circumference, while genotype FF for the FokI polymorphism was correlated with lower BMI in subjects with MS. CONCLUSION: Our study suggests that the VDR gene polymorphisms appear to be associated with MS in the Northern Chinese population. Allele B and BB genotype for BsmI are risk factors for MS. The BsmI polymorphism seems to influence waist circumference, while the FokI polymorphism influence BMI in subjects with MS.