[1] Univ Aberdeen, Sch Med Med Sci & Nutr, Epidemiol Grp, Aberdeen AB24 3FX, Scotland
[2] Cantonal Hosp, Dept Rheumatol, Fribourg, Switzerland
[3] ICRCCS Galeazzi Orthopaed Inst, Milan, Italy
[4] Klinikum Saarbrucken, Dept Internal Med 1, Saarbrucken, Germany
[5] Tech Univ Munich, Dept Psychosomat Med, Munich, Germany
[6] Cardiff Univ, Inst Infect & Immun, Sch Med, Cardiff, S Glam, Wales
[7] Copenhagen Univ Hosp, Parker Inst, Dept Rheumatol, Copenhagen, Denmark
[8] Univ Nova Lisboa, Hosp Egas Moniz, CHLO, Dept Rheumatol,CEDOC NOVA Med Sch, Lisbon, Portugal
[9] Hacettepe Univ, Dept Phys & Rehabil Med, Div Internal Med, Ankara, Turkey
[10] Finnish Inst Occupat Hlth, Helsinki, Finland
[11] Mater Misericordiae Univ Hosp, Dublin, Ireland
[12] Univ Paris 05, Hop Cochin Hotel Dieu, Ctr Douleur, Paris, France
[13] L Sacco Univ Hosp, Rheumatol Unit, Milan, Italy