However, there are some limitations: (1) we evaluated only one polymorphism located in the DPP4 gene, (2) we did not determine the activity of DPP4, (3) patients with non-premature CAD and individuals with T2DM without pCAD were not included, and (4) it is a non-prospective cross-sectional study that does not permit establishing causality. Here, DPP4 is linked to type 2 diabetes mellitus.