Psychological and biological features influencing the risk for rheumatoid arthritis

The aim of this thesis was to study the at-risk phase of RA development, in a broad spectrum of at-risk populations, with a focus on symptomatology and biomarkers. In Part I, two systematic reviews cover risk factors, screening for and prevention of RA. In Part II, we focused on symptoms and concluded that: 1. Higher scores for depressive mood and lower scores for social support are not directly related with arthritis development, but they increase musculoskeletal symptoms already in the at-risk phase; 2. A newly designed Symptoms in Persons At Risk of Rheumatoid Arthritis (SPARRA) questionnaire can be used to explore symptoms in individuals at-risk for RA; and 3. Patients with inflammatory arthritis (IA), as compared to control patients, had more musculoskeletal symptoms, infections, IA-related diseases and chronic diseases before the IA diagnosis in a large primary care database. In Part III, a wide range of markers was investigated. Serum 14-3-3η (eta) levels and change of rheumatoid factor and anti-citrullinated protein antibodies over time did not predict arthritis development, whereas performing joint ultrasonography and measuring dominant B-cell receptor (BCR) clones in peripheral blood showed potential. Especially the presence of dominant BCR clones is highly predictive of arthritis development within 3 years