1. Department of Pediatrics, University of Michigan, Ann Arbor;
2. School of Public Health, University of Alberta, Edmonton, AB;
3. Department of Biostatistics, The Fred Hutchinson Cancer Research Center, Seattle, WA;
4. Department of Pediatrics, Dana-Farber Cancer Institute, Boston, MA;
5. Departments of Pediatrics and Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY;
6. Department of Epidemiology and Cancer Control, St Jude Children's Research Hospital, Memphis, TN; and
7. Department of Pediatrics, University of Minnesota, Minneapolis