1. Mailman School of Public Health, Department of Epidemiology Columbia University Medical Center New York New York USA
2. Department of Pediatrics (Division of Pediatric Hematology, Oncology, and Stem Cell Transplantation) Columbia University Medical Center New York New York USA
3. Mailman School of Public Health, Department of Biostatistics Columbia University Medical Center New York New York USA
4. Department of Ophthalmology Hospital Infantil de Mexico, Federico Gomez Mexico City Mexico
5. Centro Medico Nacional Siglo XXI, Instituto Mexicano de Seguro Social Hospital de Pediatria Mexico City Mexico
6. Mailman School of Public Health, Department of Environmental Health Science Columbia University Medical Center New York New York USA
7. Centro de Investigacion de Nutricion y Salud Instituto Nacional de Salud Publica Cuernavaca Mexico
8. Department of Pathology Hospital Infantil de Mexico, Federico Gomez Mexico City Mexico