1. Department of Health Sciences, University of Genoa, Genoa, Italy
2. Hygiene Unit, IRCCS University Hospital “San Martino” - IST National Institute for Cancer Research, Genoa, Italy
3. Department of Health Promotion Sciences and Mother-Child Care “G. D'Alessandro” – Hygiene section, University of Palermo, Palermo, Italy
4. Clinical Epidemiology Unit, University Hospital “Paolo Giaccone”, Palermo, Italy