Objectives: To determine the prevalence of asthma symptoms among schoolchildren living on two different Brazilian Amazon islands and to identify the risk factors related to this condition.
Methods: A cross-sectional study of 400 schoolchildren (5-8 years old) using written questionnaires produced by the International Study of Asthma and Allergies in Childhood, a skin prick test (allergic sensitization), and a stool examination (for helminthic infection). Nonparametric tests were carried out, and the risk factors were identified by logistic regression.
Results: The prevalence of active asthma symptoms was markedly higher in children living on Outeiro Island (OI) than those living on Combú Island (CBI) (30.5% and 16.5%, respectively). The logistic regression identified several risk factors of asthma symptoms on CBI: parental history of asthma, night coughing in the past year, and "currently have a cat". On OI, the major risk factors were parental history of asthma, personal history of eczema, having two or more older siblings, and night coughing in the past year. The risk factors in common on both the islands were night coughing in the past year and parental history of asthma.
Conclusions: The prevalence of asthma symptoms was higher in those with a lifestyle closer to that observed in urban areas (i.e., better sanitation and hygiene), reinforcing the protective effect of a rural environment. Different risk factors were associated with asthma symptoms in schoolchildren living on OI and on CBI. This fact may reflect the environmental individuality and particularities of each island.