Dipeptidyl peptidase 4 (DPP4) is a serine exopeptidase able to inactivate various oligopeptides involved in inflammation, immunity and vascular function. Our aim was to investigate the associations between constitutive levels of DPP4 activity and inflammatory biomarkers, skin microvascular reactivity, gut peptides, insulin resistance indexes, heart rate and blood pressure variability, and measures of adiposity in subjects with different grades of glucose tolerance.