1. Unit of Hygiene and Preventive, Environmental and Occupational Medicine; Department of Diagnostics and Public Health; University of Verona; Verona Italy
2. Unit of Epidemiology & Medical Statistics; Department of Diagnostics and Public Health; University of Verona; Verona Italy
3. Neonatology and Neonatal Intensive Care Unit; Mantua Hospital ‘C. Poma’; Mantua Italy
4. Unit of Medical Statistics & Epidemiology; Department of Health Science; University of Pavia; Pavia Italy