Geographic variation in the prevalence of asthma symptoms in Spanish children and adolescents.: International Study of Asthma and Allergies in Childhood (ISAAC) phase 3, Spain

OBJECTIVE: To analyze geographic variations in the prevalence of symptoms related to asthma in Spanish children and adolescents. POPULATION AND METHODS: In 2001 and 2002, the Spanish arm of the International Study of Asthma and Allergies in Childhood (ISAAC) Phase 3 collected information on 28 445 children in the age bracket of 6-7 years in 10 metropolitan areas (A Coruna, Asturias, Barcelona, Bilbao, Cartagena, Castellon, Madrid, Pamplona, San Sebastian, and Valencia) and on 31257 adolescents in the bracket 13-14 years in 11 areas (the previously named areas plus Valladolid). An asthma symptom questionnaire was filled in by parents or the adolescents themselves. Differences in symptoms between geographic areas were analyzed by fitting a logistic regression model. The relationship between symptoms and age was analyzed by linear correlation. RESULTS: The prevalence of recent wheezing (last 12 months) ranged from 7.1% to 12.9% among 6-7-year-olds and from 7.1% to 15.3% among the 13-14-year-olds. The greatest risk of recent wheezing was observed for children in A Coruna (odds ratio [OR] = 1.96 in comparison with the area of lowest prevalence; 95% confidence interval [CI], 1.65-2.33) and Bilbao (OR = 1.83; 95% CI, 1.54-2.18) and for adolescents in A Coruna (OR = 2.38; 95% Cl, 2.04-2.79) and Asturias (OR = 2.37; 95% CI, 2.03-2.77). A strong correlation (r = 0.72) was observed between the prevalence of recent wheezing and age in each of the geographic areas. CONCLUSIONS: Considerable geographic variation in the prevalence of asthma symptoms can be seen in Spain even among young children. Symptoms are more frequent in children and adolescents who live on the Spain's northern Atlantic coast.