[1] Gothenburg Univ, Dept Rheumatol, Gothenburg, Sweden
[2] Sahlgrens Univ Hosp, Rheumatol Clin, Gothenburg, Sweden
[3] Univ Manchester, Div Musculoskeletal & Dermatol Sci, Manchester, Lancs, England
[4] Karolinska Inst, Dept Biosci & Nutr H2, Stockholm, Sweden