y Influence of antioxidants' gene variants on risk of diabetes mellitus and its complications: a systematic review

INTRODUCTION: Oxidative stress has a key role in pathophysiology of type 2 diabetes mellitus (T2DM) and its complications as a most common health problem. Due to controversial evidence regarding the association between antioxidants' gene varients and T2DM, our aim was a systematic review of the current meta-analyses. EVIDENCE ACQUISTION: All meta-analysis' studies which assessed the association of single nucleotide polymorphisms of superoxide dismutase (SOD), catalase, glutathione peroxidase (GPX), glutathione S transferase (GST), nitric oxide synthase (NOS) and nicotinamide adenine dinucleotide phosphate oxidase (NOX) with T2DM and its complications were systematically extracted from PubMed, Scopus and Web of Science databases up to January 2016. Results are reported according to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA). EVIDENCE SYNTHESIS: Among 131 articles recorded in initial search, 19 studies were in the topic just for eNOS (endothelial NOS), NOX, GST and SOD gene variants. G8941, 4b/a and T-786C variants (eNOS) were associated with DN (diabetic nephropathy). However no association between 4b/a variant and DR (diabetic retinopathy) was observed. Separate or combination of GSTM1 and GSTT1 null genotypes (GST gene) were associated with T2DM. GSTM1 and combination of GSTM1/GSTT1 null genotypes were associated with DN. Significant association between C242T variant (NOX) and T2DM or DN, and non-significant association with carotid atherosclerosis were seen. C allele of C47T variant (SOD) was protective against DN, DR and microvascular complications of diabetes. CONCLUSIONS: Finding gene polymorphisms involved in diabetes and its complications might be helpful in discovering new therapeutic approaches, as well as prevention which is currently as a main focus in personalized medicine.