1. Department of Pediatrics and Adolescent Medicine; University Hospital Rigshospitalet; Copenhagen Denmark
2. Department of Pediatrics, Section of Pediatric Oncology/Hematology; Lund University Hospital; Lund Sweden
3. Department of Public Health; University of Copenhagen; Denmark
4. Section of Biostatistics, Department of Public Health; University of Copenhagen; Denmark
5. Department of Pediatrics; Astrid Lindgrens Hospital; Stockholm Sweden
6. Department of Clinical Sciences; Queen Silvia's Children's Hospital; Gothenburg Sweden
7. Childhood Cancer Research Unit, Department of Women and Child Health; Astrid Lindgren Children's Hospital; Karolinska University Hospital; Stockholm Sweden
8. Department of Pediatrics, St. Olavs Hospital; Trondheim University Hospital; Trondheim Norway
9. Department of Pediatrics; Landspitali University Hospital; Reykjavík Iceland
10. Department of Paediatrics; University of Tampere; Finland
11. Department of Pediatric Oncology; Skejby Hospital; Aarhus Denmark
12. Institute of Clinical Medicine; University of Copenhagen; Denmark
13. Division of Pediatric Hematology/Oncology, Perlmutter Cancer Center; NYU Langone Medical Center; New York City New York