1. University of Bern; Division of Clinical Epidemiology and Biostatistics, Institute of Social and Preventive Medicine; Finkenhubelweg 11 Bern Switzerland 3012
2. Ben-Gurion University of the Negev; Department of Physical Therapy, Recanati School for Community Health Professions, Faculty of Health Sciences; Beer Sheva Israel 84105
3. Maastricht University; Epidemiology Department; P.O. Box 616 Maastricht Netherlands NL-6200 MD
4. Faculty of Medicine; Department of Medicine; Chulalongkorn University 1873 Rama IV Road, Pathumwan Bangkok Thailand 10330
5. University of Ottawa; School of Rehabilitation Sciences, Faculty of Health Sciences; 451 Smyth Road Ottawa Ontario Canada K1H 8M5
6. University Hospital; Department for Rheumatology, Clinical Immunology, and Allergology; Inselspital Bern Switzerland