1. Department of Translational Medicine Università del Piemonte Orientale Novara Italy
2. Piedmont Centre for Drug Addiction Epidemiology A.S.L. TO3 Torino Italy
3. Department of Clinical and Biological Sciences University of Torino Torino Italy
4. Department of Translational Medicine Avogadro University Novara Italy
5. National Drug and Alcohol Research Centre UNSW Sydney Sydney Australia
6. Population Health Science, Bristol Medical School University of Bristol Bristol UK
7. Department of Biomedical Sciences University of Cagliari Cagliari Italy
8. Department of Epidemiology Lazio Regional Health Service Rome Italy