1. Dermatology Department Hospital Clinic of Barcelona University of Barcelona Barcelona Spain
2. Institut d'Investigacions Biomediques August Pi I Sunyer (IDIBAPS) Barcelona Spain
3. Clinical Biochemistry Department Hospital Clinic of Barcelona University of Barcelona Barcelona Spain
4. Dermatology Clinic Department of Medical Sciences University of Turin Turin Italy
5. Medical Statistics Core Facility Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and Hospital Clinic Barcelona Spain
6. Biostatistics Unit Faculty of Medicine Universitat Autònoma de Barcelona Barcelona Spain