INS and type 2 diabetes mellitus: About glucose‐linked markers, serum insulin levels at 30 min (p = .041) and 60 min (p = .028), insulin AUC (p = .033), and C‐peptide at 30 min (p = .050) were significantly decreased in IFG and IGT groups, whereas in T2DM patients were found reduced serum insulin (p = .012) and C‐peptide values (p = .022) at 120 min, as well as C‐peptide AUC (p = .010).