3 Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland.
4 School of Engineering and Natural Sciences, University of Iceland, Reykjavik, Iceland.
5 Landspitali University Hospital, Reykjavik, Iceland.
6 Department of Clinical Immunology, Zealand University Hospital, Køge, Denmark.
7 Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
8 Danish Headache Center, Dept. Neurology, Rigshospitalet-Glostrup, Glostrup, Denmark.
9 Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
10 Institute of Biological Psychiatry, Mental Health Services, Copenhagen University Hospital, Copenhagen, Denmark.
11 Lundbeck Foundation for GeoGenetics, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark.
12 Department of Orthopaedic Surgery, CAG ROAD-Research OsteoArthritis Denmark, Copenhagen University Hospital, Hvidovre, Denmark.
13 Research Unit for Musculoskeletal Function and Physiotherapy, Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
14 The Research Unit PROgrez, Department of Physiotherapy and Occupational Therapy, Næstved-Slagelse-Ringsted Hospitals, Næstved, Denmark.
15 Department of Clinical Immunology, Copenhagen University Hospital, Copenhagen, Denmark.
16 Department of Clinical Immunology, Aarhus University Hospital, Aarhus, Denmark.
17 Department of Clinical Immunology, Aalborg University Hospital, Aalborg, Denmark.
18 Department of Neurosurgery, Landspitali University Hospital, Reykjavik, Iceland.
19 Health Care Institution of West Iceland, Stykkisholmur, Iceland.