When MetS patients were divided into two groups based on the median insulin iAUC reduction rate (higher group ≥ 34%, n = 14; lower group < 34%, n = 13), those in the higher group showed a significantly higher rate of change in the iAUCs of TG and FMD than those in the lower group (TG, 31.0% vs. 10.8%; P = 0.033; FMD, 39.2% vs. 9.8%; P = 0.037). This evidence concerns the gene INS and metabolic syndrome.