1. Clinical Epidemiology and Biostatistics School of Medical Sciences Örebro University ÖrebroSweden
2. Department of Dermatology Karlstad Central Hospital KarlstadSweden
3. Department of Dermatology Skåne University Hospital MalmöSweden
4. Department of Dermatology Örebro University ÖrebroSweden
5. Faculty of Epidemiology and Population Health London School of Hygiene and Tropical Medicine London U.K.
6. Clinical Epidemiology Unit Department of Medicine Karolinska Institutet StockholmSweden
7. Department of Epidemiology and Public Health University College London London U.K.