Overall, a substantial association was found between the eNOS G894T polymorphism and an increased risk of T2DM (GT vs. GG: OR = 1.32, 95% CI = 1.14–1.52; TT vs. GG: OR = 1.39, 95% CI = 1.09–1.78; GT + TT vs. GG: OR = 1.36, 95% CI = 1.17–1.57; TT vs. GG + GT: OR = 1.23, 95% CI = 1.00–1.51; T vs. G: OR = 1.29, 95% CI = 1.14–1.45, Table 7; Figure 3). The gene discussed is NOS3; the disease is type 2 diabetes mellitus.