Independent associations of polymorphisms in vitamin D binding protein (GC) and vitamin D receptor (VDR) genes with obesity and plasma 25OHD3 levels demonstrate sex dimorphism

We investigated a possible association between polymorphisms in vitamin D binding protein (GC) and vitamin D receptor (VDR) genes and obesity in Bahraini adults. For this purpose, 406 subjects with varying body mass indexes (BMIs) were selected. Plasma levels of 25-hydroxyvitamin D3 (25OHD3) were measured by chemiluminescence immunoassay. Six single nucleotide polymorphisms, 2 in the VDR gene (rs731236 TC and rs12721377 AG) and 4 in the GC gene (rs2282679 AC, rs4588 CA, rs7041 GT, and rs2298849 TC), were genotyped by real-time polymerase chain reaction. We found that the rs7041 minor allele (G) and rare genotype (GG) were associated with higher BMI (p = 0.007 and p = 0.012, respectively), but they did not influence 25OHD3 levels. However, the minor alleles of rs2282679 (A) and rs4588 (C) were associated with low 25OHD3 plasma levels (p = 0.039 and p = 0.021, respectively), but not with BMI. Having categorized the subjects based on their sex, we found that (i) rs7041 GG associated with high BMI in females ...