1. Department of Epidemiology - IRCCS Istituto di Ricerche Farmacologiche “Mario Negri”; Milan Italy
2. Department of Dermatology; Azienda Ospedaliera Papa Giovanni XXIII; Centro Studi GISED; Bergamo Italy
3. Université Paris Descartes; 75015 Paris France
4. INSERM, Unité 1151; Paris France
5. Department of Clinical Sciences and Community Health; Università degli Studi di Milano; Milan Italy