Association between TNF-α-308G/A polymorphism and diabetic nephropathy risk: a meta-analysis

TNF-alpha -308G/A polymorphism has been implicated in the susceptibility of diabetic nephropathy, but studies have reported inconclusive results. The present study investigated the relationship between -308G/A polymorphism in the TNF-alpha gene and diabetic nephropathy risk by meta-analysis. Data from PubMed, Embase, Ovid, Cochrane Library, China National Knowledge Infrastructure, Wanfang, VIP and China Biology Medicine disc databases were evaluated and analyzed. Statistical analysis was performed using RevMan 4.2 and Stata 10.0 software. A total of 1,277 diabetic nephropathy cases and 1,740 controls in eight case-controlled studies were identified for data analysis. The results suggested that A allele carriers (GA + AA) may not have an altered risk of diabetic nephropathy when compared with homozygote GG carriers with boarder-line statistical significance (OR = 0.84, 95 % CI = 0.71-1.00, p = 0.05 for GA + AA vs. GG). However, in Asian subgroup analysis, the A allele variant was associated with a decreased diabetic nephropathy risk (OR = 0.69, 95 % CI = 0.51-0.94, p = 0.02 for GA + AA vs. GG). Meta-analysis suggests that the A allele of TNF-alpha -308G/A polymorphism might be protective against diabetic nephropathy with ethnic selectivity. Future studies are needed to validate these findings.