RESUMO
OBJECTIVE: To investigate factors associated with the severity of childhood asthma. METHODS: We conducted a case-control study in a group of Brazilian children (2-12 years old) with diagnosis of asthma attending the pediatric pulmonology clinic of a teaching hospital. The study sample consisted of cases (children with persistent asthma) and controls (children with intermittent asthma). Data were collected through an interview with the child's parent or caretaker using a standard questionnaire. Association between asthma severity and studied variables was assessed by calculating odds ratios (OR) and 95% confidence interval (95% CI) through logistic regression test. RESULTS: 171 children were included in this study, of which 104 (61%) had persistent asthma and 67 (39%) had intermittent asthma. Onset of the disease before 2 years of age, paternal educational level lower than 9 years, and low household income (≤1 minimum wage per month) were independent risk factors for persistent asthma, with adjusted OR (95% CI) of 2.56 (1.01-6.48), 2.49 (1.04-5.99), and 4.36 (1.06-17.87), respectively. Regular consumption of fruits during the last 30 days was inversely associated with the risk of having persistent asthma, with an adjusted OR (95% CI) of 0.19 (0.04-0.97). CONCLUSIONS: Early onset of the disease, low paternal education, and low household income are independent risk factors for persistent childhood asthma. Regular consumption of fruits appears to be a protective factor against more severe asthma in children.