Abstract: Objective  To investigate the association between vitamin D receptor(VDR) gene ApaI polymorphism and impaired glucose tolerance (IGT) and blood serum 25-dihydroxyvitamin D (25-OH-VD3). Methods  VDR genotype in 105 cases of IGT(IGT group) and 105 normal controls(NC group) was detected with PCR-RLFP; serum 25-OH-VD3 was tested with enzyme linked immunosorbent assay(ELISA); relevant clinical and biochemical indexes were also examined. The alleles frequencies and genotype frequencies of VDR ApaI gene were compared between the two groups, and serum 25-OH-VD3 and other indexes were compared between different genotypes. Results  Compared with controls, subjects with IGT had a markedly lower level of serum 25-OH-VD3 (22.05±2.37 vs 32.04±2.64), P<0.05. Level of serum 25-OH-VD3 lower than 30ng/mL accounted for 63.8% of all cases. There was significant difference in the distribution of VDR genotype frequencies and alleles frequencies between the two groups (P<0.05). The prevalence of VDR gene genotype frequencies and alleles frequencies in IGT was significantly different from the controls. Serum 25-OH-VD3 was higher in VDR genotype AA and Aa groups than in genotype aa groups (P<0.05). Multivariate logistic regression analysis showed that the levels of low density lipoprotein cholesterol(LDL-C), BMI, age, VDR gene ApaI presented a positive correlation with IGT, while 25-OH-VD3 exhibited a negative correlation with IGT. Conclusion  Vitamin D deficiency is prevalent. Allele a of VDR may be a genetic marker susceptible to IGT. Serum 25-OH-VD3 is associated with VDR gene polymorphism.

Key words: Vitamin D receptor gene polymorphism, Serum 25-dihydroxyvitamin D, Impaired glucose tolerance