Valgerdur Sigurdardottir1, Anna Svärd2. 1. Center for Clinical Research (CKF) Dalarna, Uppsala University, Falun, Sweden; Department of Rheumatology, Falun General Hospital, Falun, Sweden. Electronic address: valgerdur.sigurdardottir@ltdalarna.se. 2. Center for Clinical Research (CKF) Dalarna, Uppsala University, Falun, Sweden; Department of Rheumatology, Falun General Hospital, Falun, Sweden.