The overall results showed evidence of significant association between the APOA5 -1131T/C polymorphism and T2DM risk, suggesting that the APOA5 -1131T/C polymorphism was a risk factor for T2DM (for C allele vs. T allele: OR = 1.28, 95% CI = 1.17–1.40, p<0.00001; for C/C vs. T/T: OR = 1.57, 95% CI = 1.35–1.83, p<0.00001; for C/C vs. T/C+T/T: OR = 1.36, 95% CI = 1.18–1.57, p<0.0001; for C/C+T/C vs. T/T: OR = 1.32, 95% CI = 1.16–1.51, p<0.0001). This evidence concerns the gene APOA5 and type 2 diabetes mellitus.