The meta-analysis showed that the incidence of type 2 diabetes was higher in the ADA I-IFG, ADA I-IGT (IGT+NFG), and ADA IGT+IFG groups than in the ADA NFG+NGT group (RR [95% CI] of 2.66 [2.00, 3.54], 3.34 [2.81, 3.97], and 6.10 [4.72, 7.88]), respectively (see Figures 3B, –D). This evidence concerns the gene ENAM and type 2 diabetes mellitus.