1. Max Planck Institute for Demographic Research, Rostock, Germany
2. German Center for Growth, Development and Health Encouragement during Childhood and Youth, Berlin, Germany
3. Section of Perinatal Medicine, Department of Obstetrics, Technical University of Munich, Germany
4. Division of Neonatology, Department of Pediatrics, McMaster University, Hamilton, Canada
5. Diakoniekrankenhaus Rotenburg (Wümme) gGmbH, Rotenburg (Wümme), Germany
6. Institute of Occupational, Social and Environmental Medicine, University Medical Center Göttingen, Germany