1. Center of Excellence in Maternal, Child, and Adolescent Health, University of California Berkeley School of Public Health, Berkeley, California, USA.
2. Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.
3. School of Medicine, Department of Epidemiology and Public Health, University of Basel, Basel, Switzerland.
4. Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, Berkeley, Berkeley, California, USA.