In the following ethnic subgroup analysis, we discovered a significant association between eNOS 4b/4a polymorphism and T2DM susceptibility in the Asian population (bb vs. aa: OR = 0.44, 95% CI = 0.23–0.84; ab + bb vs. aa: OR = 0.45, 95% CI = 0.24–0.86; bb vs. aa + ab: OR = 0.73, 95% CI = 0.59–0.91; b vs. a: OR = 0.71, 95% CI = 0.57–0.88, Table 6; Figure 2). This evidence concerns the gene NOS3 and type 2 diabetes mellitus.