1 Pediatric Unit, Department of Medical and Surgical Sciences, University of Bologna, S. Orsola-Malpighi Hospital, Pad 16, via Massarenti 11, 40138 Bologna, Italy.
2 Department of Clinical Epidemiology & Biostatistics, McMaster University, Hamilton, Ontario Canada ; Tecnologico de Monterrey School of Medicine, Monterrey, Mexico.
3 Department of Clinical Epidemiology & Biostatistics, McMaster University, Hamilton, Ontario Canada ; Department of Medicine, McMaster University, Hamilton, Ontario Canada.
4 Pediatric Hospital Bambino Gesù, Rome, Vatican City, Italy.
5 Department of Pediatrics, Nippon Medical School, Tokyo, Japan.
6 Department of Clinical Epidemiology & Biostatistics, McMaster University, Hamilton, Ontario Canada.
7 Department of Child and Maternal Medicine, University of Milan Medical School at the Melloni Hospital, Milan, Italy.
8 Department of Clinical Epidemiology & Biostatistics, McMaster University, Hamilton, Ontario Canada ; Faculty of Medicine, University of Toronto, Toronto, Ontario Canada.