1. Department of Epidemiology, Columbia University New York, NY, USA
2. Department of Community Health Sciences, Aga Khan University, Karachi, Pakistan
3. Department of Pediatrics, Section of Nutrition, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
4. Department of Obstetrics and Gynecology, Columbia University, New York, NY, USA
5. RTI International, 3040 E. Cornwallis Road, Research Triangle Park, NC, USA
6. Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA