1. Department of Medical Epidemiology and Biostatistics, Karolinska Institutet , Stockholm , Sweden
2. Dermatology and Venereology Division, Department of Medicine (Solna), Karolinska Institutet , Stockholm , Sweden
3. Dermato-Venereology Clinic, Karolinska University Hospital , Stockholm , Sweden
4. School of Medical Sciences, Faculty of Medicine and Health, Örebro University , Örebro , Sweden