Risk factors for acute asthma in tropical America: a case-control study in the City of Esmeraldas, Ecuador

Background\ud \ud Despite the high asthma rates described in Latin America, asthma risk factors in poor urban settings are not well established. We investigated risk factors for acute asthma among Ecuadorian children.\ud \ud Methods\ud \ud A matched case-control study was done in a public hospital serving a coastal city. Children with acute asthma were age- and sex-matched to non-asthmatics. A questionnaire was administered and blood, as well as stool, and nasopharyngeal swabs were collected.\ud \ud Results\ud \ud 60 cases and 119 controls aged 5-15 years were evaluated. High proportions of cases were atopic with population attributable fractions for atopy of 68.5% for sIgE and 57.2% for SPT. Acute asthma risk increased with greater titers of mite IgE (3.51-50 kU/L vs. 50kU/L vs.