1 Department of Pediatrics, Turku University Hospital and University of Turku, Kiinamyllynkatu 4-8, 20520 Turku, Finland.
2 Department of Pediatric and Adolescent Medicine, Drammen Hospital, Vestre Viken Hospital Trust, Norway; Department of Clinical Medicine, University of Bergen, Norway.
3 Department of Women's and Children's Health, Uppsala University Children's Hospital, SE-75185 Uppsala, Sweden.
4 Hospital Universitario Gregorio Marañón, Department of Pediatrics, O'Donnell 50, 28009 Madrid, Spain.
5 Tartu University Hospital and University of Tartu, Department of Pediatrics, N. Lunini 6, 51014 Tartu, Estonia.
6 Tallinn Children's Hospital, Clinic of Pediatrics, Tervise 28, 13619 Tallinn, Estonia; University of Tartu, Department of Pediatrics, Lunini 6, 51014 Tartu, Estonia.
7 University Hospital North Norway, N-9038 Tromsø, Norway.
8 Department of Neonatology, Karolinska University Hospital, Stockholm, Sweden.
9 Department Women's and Children's Health, Karolinska Institute, Stockholm, Sweden.
10 Centre for the at-Risk Infant, Scientific Institute, IRCCS Eugenio Medea, Via Don L. Monza 20, 23842 Bosisio Parini, LC, Italy.
11 Department of Nursing Science, University of Turku, 20014 Turku, Finland.