1. Occupational Medicine, Department of Clinical and Experimental Medicine, University of Catania, 95124 Catania, Italy
2. Occupational Medicine, Department of Clinical and Molecular Sciences, Polytechnic University of Marche, 60121 Ancona, Italy
3. Occupational Health and Safety Unit, Provincial Health Agency of Siracusa, 96100 Siracusa, Italy
4. Occupational Medicine Unit, “Garibaldi” Hospital of Catania, 95123 Catania, Italy
5. Prevention and Protection Unit, Provincial Health Agency of Ragusa, 97100 Ragusa, Italy
6. Unit of Biostatistics, Epidemiology and Public Health, Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova, 35131 Padova, Italy