1. Unit of Epidemiology; Regional Health Service ASL TO3; Grugliasco (Turin) Italy
2. Department of Clinical and Biological Sciences; University of Turin; Orbassano (Turin) Italy
3. Department of Epidemiology and Environmental Health; Regional Environmental Protection Agency (ARPA Piemonte); Turin Italy
4. Department of Public Health, Prevention and Security Area Work Environments; Local Health Authority; Bologna Italy