1. Department of Dermatology Neuro and Orthopaedic Clinic University Hospital of North Norway Tromsø Norway
2. Department of Community Medicine Faculty of Health Sciences UiT The Arctic University of Norway Tromsø Norway
3. Department of Rheumatology Dermatology and Infectious Diseases The Olafia Clinic Oslo University Hospital Oslo Norway
4. Institute of Clinical Medicine University of Oslo Oslo Norway
5. Department of Microbiology and Infection Control University Hospital of North Norway Tromsø Norway
6. Division of Nutritional Sciences Cornell University Ithaca NY U.S.A
7. Department of Public Health Division of Biostatistics and Epidemiology Weill Cornell Medical College New York NYU.S.A