We analyzed data collected from 1,271 out of 1,445 children aged 4–11 years, enrolled in the SCAALA Program
(Social Change in Asthma and Allergies in Latin America) . One hundred and seventy-four of the 1,445 children
were excluded because of missing data. The study population comprised a cohort of children living in 24 microareas
in poor neighborhoods scattered throughout the city, originally constituted to evaluate the impact of a sanitation
program on health outcomes when the children were aged 0–4 years. Cohorts of different children were recruited in 1999, 2000 and 2002, with a total of 2,973 children . In these surveys, the child’s guardians were interviewed using a standard questionnaire to collect data on housing, sanitation, and socioeconomic conditions . Allergic outcomes were evaluated in the cohort when the children were aged 4–11 years in 2005 using an ISAAC phase II questionnaire translated into Portuguese.