1. From the Department of Otolaryngology (Dr Chadha), Hospital for Sick Children, Toronto, Ontario, Canada; the Departamento Materno-Infantil (Dr Zhang), Universidade Federal do Rio Grande, Rio Grande, RS, Brazil; the Division of Epidemiology and Public Health (Dr Mendoza-Sassi), Department of Internal Medicine, Centro, Brazil; and the Division of Epidemiology, Department of Maternal and Child Health (Dr Csar), Rio Grande, RS, Brazil.