Prevalence and severity of asthma and related symptoms in 6- to 7-year-old schoolchildren of Rio de Janeiro using of the ISAAC questionnaire by telephone survey.

OBJECTIVE: To evaluate the prevalence and severity of asthma and its association with sex in 6- to 7-year-old schoolchildren from the city of Rio de Janeiro (RJ), obtained by a telephone survey. METHODS: A cross-sectional study using the International Study of Asthma and Allergies in Childhood (ISAAC) Written Questionnaire for Asthma adapted and validated by telephone interviews was conducted. The random sample was recruited systematically, without replacement, taking into account the proportion of school classes and students in each regional coordination of the Municipal Secretariat of Education, which supplied the students' telephone numbers. The data were collected by a polling company from May to July 2010. Prevalence ratios (PRs) and 95% confidence intervals (95% CI) were compared using the difference in proportions test suitable for large samples to analyze the association between asthma and sex. RESULTS: In total, 3216 interviews from parents/caregivers of children were analyzed; 51.4% of the children were males. Mothers were the primary respondents (71.9%). The prevalence rates of "wheezing ever" and "wheezing in the last 12 months" were 52.2% and 20.9%, respectively, and were significantly higher among boys (PR: 1.10, 95% CI: 1.03-1.18 and PR: 1.27, 95% CI: 1.10-1.45). The same pattern was observed for "asthma ever" (PR: 1.44, 95% CI: 1.12-1.85) and for "severe asthma" (PR: 1.42, 95% CI: 1.11-1.82). CONCLUSION: The prevalence of asthma was high among RJ's students. Most of the indicators of the disease were more prevalent among boys. Our results were similar to those observed in other Brazilian and international centers using the traditional ISAAC protocol. The use of this method can be an alternative for epidemiological studies of childhood asthma especially in areas where the telephone coverage is high.

Validity and reproducibility of the asthma core International Study of Asthma and Allergies in Childhood (ISAAC) written questionnaire obtained by telephone survey.

OBJECTIVE: To assess the reproducibility and validity of the International Study of Asthma and Allergies in Childhood (ISAAC) asthma written questionnaire (IAWQ) for 6- to 7-year-old children administered to their parents/caregivers through a telephone interview. METHODS: Our study included 100 children selected from three health units in Rio de Janeiro, Brazil. In total, 50 asthmatic and 50 non-asthmatic children were evaluated; all participants were required to own a household telephone line. Initially, telephone interviews were conducted with the parents/caregivers using the IAWQ. After 2 weeks, parents/caregivers were invited to complete the IAWQ under supervision provided by the researchers. After fifteen days, the telephone interviews were repeated. The reproducibility between the two telephone interviews was assessed using kappa (κ) coefficients; the construct validity was assessed by comparing the answers obtained in the initial telephone interview in both groups according to the clinical diagnosis of asthma performed by a specialist using sensitivity and specificity coefficients. RESULTS: Overall, data from 75 children (39 asthmatics) were analyzed, as 25 patients were excluded from the study (11 did not answer phone calls and the responding parents/caregivers for 14 patients were not the same in all study phases). Perfect agreement was observed for the indicator "wheezing in the last 12 months" (κ = 1), while substantial agreement was observed for the "wheezing with exercise," "speech limited by wheezing," and "asthma ever" indicators (κ range, 0.7-0.8). The sensitivity and specificity for "wheezing within the last 12 months" were 64.1% (95% confidence interval (CI), 47.2-78.8) and 88.9% (95% CI, 73.9-96.9), respectively. For the "asthma ever" indicator, the sensitivity and specificity were 87.2% (95% CI, 77.6-95.7) and 100% (95% CI, 90.3-1), respectively. Questionnaire specificity was high for all asthma severity indicators. CONCLUSIONS: The IAWQ for children aged 6-7 years adapted for telephone interviews showed good reproducibility and adequate validity with an ability to distinguish between asthmatic and non-asthmatic participants. Thus, this method could be utilized in epidemiological studies on childhood asthma in locations where telephone lines are available.