[1] Univ Tecnol Equinoccial, Fac Ciencias Salud Eugenio Espejo, Quito, Ecuador
[2] Marilia Med Sch, Dept Gen Internal Med, Marilia, Brazil
[3] Marilia Med Sch, Clin Epidemiol Unit, Marilia, Brazil
[4] Res Inst Trop Med, Sickle Cell Unit, Kingston 7, Jamaica