The main strengths of our study are the detailed phenotype assessment of renal function during the 10-year follow-up of the SURGENE cohort, the replication of our findings in independent cohorts, the assessment of possible confounding effects of diabetic retinopathy, and the genotyping of tagSNPs covering all haplotype blocks containing SOD2. Moreover, we also investigated associations of diabetic nephropathy and SOD2 genotypes with two markers of redox status, AOPP and SOD activity. This evidence concerns the gene SOD2 and diabetic kidney disease.