Association of the extracellular superoxide dismutase Arg 213 Gly and Ala 40 Thr polymorphisms with the susceptibility to type 2 diabetes mellitus in a Chinese population

We investigated the association between Extracellular superoxide dismutase (EC-SOD) Arg213Gly and Ala40Thr polymorphisms in the risk of Type 2 Diabetes Mellitus in a Chinese population. A total of 205 patients with type 2 diabetes mellitus and 226 control subjects were enrolled from the First Affiliated Hospital of Xinxiang Medical University. Genotyping of EC-SOD Arg213Gly and Ala40Thr was performed using polymerase chain reaction restriction fragment length polymorphism method. The Chi-square test revealed a statistically significant difference in the genotype frequencies of EC-SOD Ala40Thr (χ2 = 8.27, P = 0.02) between type 2 diabetes mellitus patients and control subjects. Using unconditional regression analysis, we observed that the AA genotype of EC-SOD Ala40Thr was correlated with a higher risk of developing type 2 diabetes mellitus compared to the GG genotype, and the adjusted OR (95% CI) was 2.20 (1.27-3.82). Moreover, the A allele of EC-SOD Ala40Thr had 1.47 fold risk of developing type 2 diabetes mellitus when compared with the G allele (adjusted OR = 1.53, 95% CI = 1.15-2.04). However, no significant association was found between EC-SOD Arg213Gly polymorphism and development of type 2 diabetes mellitus. In summary, our study suggests that individuals carrying the AA genotype and A allele of EC-SOD Ala40Thr expose higher risk to type 2 diabetes mellitus significantly with regardless of age and gender.