1. From the Joint Program in Neonatology (Beth Israel Deaconess Medical Center, Brigham and Women's Hospital, Children's Hospital and Harvard Medical School) and Harvard School of Public Health, Boston, Massachusetts; the
2. Department of Child Health, University of Dundee and Ninewells Hospital and Medical School, Dundee, United Kingdom; and the
3. Department of Pediatrics, University of British Columbia and the Centre for Health Evaluation Research, BC Research Institute for Children's and Women's Health, Vancouver, British Columbia, Canada.