The EU project ENDOTARGET aims to improve the quality of life of people with rheumatic diseases. As part of a population cohort analysis, preliminary analyses provided initial insights into the distribution of biomarkers by gender, age, body mass index (BMI) and disease type (OA, RA, SpA), as well as differences between control and disease groups. Focused cohort studies and in vitro investigations analysed the role of SE and intestinal permeability in RA, SpA and related inflammatory diseases.