1. Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Canada.
2. Hematology Site Team, Juravinski Cancer Centre, Hamilton, Canada.
3. Service of Hematology-Oncology, McMaster Children's Hospital, Hamilton, Canada.
4. Hematology Site Team, Grand River Cancer Centre, Kitchener, Canada.
5. Child Health Evaluative Sciences, Hospital for Sick Children, Toronto, Canada.
6. Department of Pediatrics, McMaster University, Hamilton, Canada.