Centers for Disease Control and Prevention, National Center for Environmental Health, Atlanta, USA; Agency for Toxic Substances and Disease Registry, Division of Toxicology and Human Health Sciences, Atlanta, USA. Electronic address: ZJLi@cdc.gov. Medical University of South Carolina, Charleston, USA. Instituto de Investigación Nutricional, Lima, Perú; Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Universidad Peruana Cayetano Heredia, Lima, Perú. Agency for Toxic Substances and Disease Registry, Division of Toxicology and Human Health Sciences, Atlanta, USA. Centers for Disease Control and Prevention, National Center for Environmental Health, Atlanta, USA. Instituto de Investigación Nutricional, Lima, Perú. Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland. Universidad Peruana Cayetano Heredia, Lima, Perú; University of Georgia, Athens, USA.