[Relationship between vitamin D receptor gene polymorphisms and gestational diabetes mellitus: a case-control study]

Objective: To investigate the relationship between vitamin D receptor (VDR) gene polymorphisms and gestational diabetes mellitus (GDM) and provide evidence for the study of the mechanism of GDM. Methods: A case-control study design was used to study pregnant women who delivered in the obstetrics department of the First Hospital of Shanxi Medical University from March 1, 2012 to July 30, 2014. Of these, 334 cases were diagnosed with GDM and were matched 1∶1 by age, gestation time and residence to corresponding healthy controls. DNA genotyping was performed for the study subjects, and those with genotyping deletions >10% were excluded. Finally 323 cases and 320 controls were included in the study. Under co-dominant, dominant, recessive, and allele genetic models, unconditional logistic regression analysis on the relationship between VDR gene locus polymorphism and GDM was conducted. And software Haploview was used to analyze the relationship between haplotype and GDM. Results: At the genetic level, VDR gene was associated with the risk of developing GDM (P<0.05). After adjusting for pre-pregnancy body mass index, family history of diabetes, it was found that rs7967152 loci was associated with an increased risk of developing GDM (AC vs. AA, OR=1.58, 95%CI: 1.13-2.21; AC+CC vs. AA, OR=1.58, 95%CI: 1.15-2.18; C vs. A, OR=1.41, 95%CI: 1.10-1.82) and rs2238140 loci was associated with an increased risk of developing GDM (AA vs. GG, OR=2.24, 95%CI: 1.19-4.20; GA+AA vs. GG, OR=1.48, 95%CI: 1.07-2.03; A vs. G, OR=1.43, 95%CI: 1.11-1.83). Carrying rs2853564 locus AG genotype and AG+GG genotype (OR=1.46, 95%CI: 1.04-2.05; OR=1.45, 95%CI: 1.05-2.00) compared with carrying AA genotype and carrying rs2853566 locus AG genotype and AG+GG genotype (OR=1.43, 95%CI: 1.03-2.00; OR=1.41, 95%CI: 1.02-1.94) compared with carrying AA genotype were risk factors for GDM. Haplotype block consisting of rs1544410, rs7967152 in the VDR gene with GC haplotype was a risk factor for GDM(OR=1.50, 95%CI: 1.15-1.97). Conclusions: VDR gene rs7967152, rs2238140, rs2853564, rs2853566 locus polymorphisms and block (rs1544410, rs7967152) GC haplotype were associated with an incrased risk of developing GDM.