1. From the Department of Hygiene and Epidemiology, Athens University Medical School, Athens, Greece;
2. Department of Epidemiology, Harvard School of Public Health, and
3. Joint Program in Neonatology, Harvard Medical School, Boston, Massachusetts;
4. Neonatal Department, Alexandra Maternity Hospital, Athens, Greece;
5. Division of Neonatology, Department of Pediatrics, University of Patras, Medical School, Patras, Greece; and
6. Neonatal Intensive Care Unit, Elena Venizelou Maternity Hospital, Athens, Greece.