SOD2 gene Val16Ala polymorphism is associated with macroalbuminuria in Mexican Type 2 Diabetes patients: a comparative study and meta-analysis

Background: Several studies in type 2 diabetes patients have shown significant associations between the SOD2 gene Val16Ala polymorphism and albuminuria, but this association has not been explored in the Mexican population. Methods: We evaluated the association between the SOD2 gene Val16Ala polymorphism (rs4880) and macroalbuminuria in a sample of 994 unrelated Mexican type 2 diabetes patients. The study included 119 subjects with urinary albumin >300 mg/dL and 875 subjects with urinary albumin <= 30 mg/dL. Genotyping of the SOD2 gene Val16Ala SNP was carried out with Real-Time Polymerase Chain Reaction (RT-PCR). Results: The frequency of the TT genotype was 6.7% higher in participants with macroalbuminuria than in the normoalbuminuria group (16.8% vs. 10.1%). Using a logistic regression analysis, we observed that individuals with the CC genotype had significantly lower risks of macroalbuminuria than those with the TT genotype (OR=0.42, p=0.034). We carried out a meta-analysis combining our data with data from four previous studies and estimated an odds ratio (95% CI) for the C allele (with respect to the reference T allele) of 0.65 (0.52-0.80, p<0.001). Conclusions: A significant association was found between the SOD2 Val16Ala polymorphism and macroalbuminuria in a sample of Mexican type 2 diabetes patients.