TNF and type 2 diabetes mellitus: The meta-analysis showed a significant association between TNF-α −308G/A and T2DM risk in the allele model (OR = 1.239, 95% CI = 1.108–1.385, P=0.000); the dominant model (OR = 1.280, 95% CI = 1.116–1.469, P=0.000); the recessive model (OR = 1.446, 95% CI = 1.154–1.813, P=0.001); the overdominant model (OR = 1.181, 95% CI = 1.041–1.341, P=0.008); and the codominant model (OR = 1.691, 95% CI = 1.310–2.184, P=0.000).