In the remaining time points of OGTT, insulin levels in IH-1h were significantly higher than in both prediabetes-IDF and NGT at 1h-PG, while significantly lower in 2h-PG, while there was no difference between T2D-IDF and prediabetes-IDF at any time point (for details, see Figure 5b). Here, INS is linked to type 2 diabetes mellitus.