1. Department of Occupational Medicine; Haukeland University Hospital; 5021 Bergen Norway
2. Department of Dermatology; Haukeland University Hospital; 5021 Bergen Norway
3. Department of Global Public Health and Primary Care, Centre for International Health; University of Bergen; 5021 Bergen Norway
4. Department of Clinical Science; University of Bergen; 5021 Bergen Norway
5. Faculty of Medicine, Department of Public Health and General Practice, HUNT Research Centre; NTNU, Norwegian University of Science and Technology; 7600 Levanger Norway