1. Department of Medicine, Surgery and Pharmacy, University of Sassari, Padre Manzella 4 Street, 07100 Sassari, Italy
2. Department of Humanities and Social Sciences, University of Sassari, Padre Manzella 4 Street, 07100 Sassari, Italy
3. Clinical Epidemiology and Medical Statistics Unit, Department of Medical, Surgical and Pharmacological Sciences, University of Sassari-Padre Manzella 4 Street, 07100 Sassari, Italy
4. Biomedical Science PhD School, Biomedical Science Department, University of Sassari, Padre Manzella 4 Street, 07100 Sassari, Italy
5. Copan Italia SpA, 25125 Brescia, Italy
6. Department of Medicine and Surgery, University of Milano-Bicocca, Cadore 48 street, 20900 Monza, Italy