[1] McMaster Univ, Dept Hlth Res Methods Evidence & Impact, Hamilton, ON, Canada
[2] Inst Mexicano Seguro Socia, Ctr Med Nacl Siglo 21, Med Res Unit Biochem, Hosp Especialidades, Mexico City, DF, Mexico
[3] Inst Mexicano Seguro Social, Hlth Promot Div, Mexico City, DF, Mexico
[4] Inst Nacl Salud Publ, Ctr Invest Enfermedades Infecciosas, Cuernavaca, Morelos, Mexico
[5] McMaster Univ, Dept Pathol & Mol Med, Hamilton, ON, Canada