Fig. 1

Altruism and scientific advancement as major motives. Participants reported their motivation to participate by choosing from four fixed motives and/or an open option called “other motives.” Most participants were motivated either by altruism or scientific advancement, while more than half of the RA patients and RA-risk individuals reported that the positive attitude of their own health care professional towards this study was one of the reasons for them to partake. Detailed explanations of “other motives” can be found in Additional file 3. Overall includes RA, RA-risk, and HC individuals. RA, rheumatoid arthritis patients; RA-risk, individuals at risk for developing RA; HC, healthy controls. *Not applicable