[Prevalence and severity of asthma in 13-14-year-old children in Bilbao].

OBJECTIVE: The objective of this study was to know the prevalence and severity of bronchial asthma in 13-14 year old children living in Bilbao, a seacoast industrial town in the North of Spain. PATIENTS AND METHODS: A sample of 13-14 year old children living in Bilbao was studied. Random sampling amongst school centers was done. Fifty-eight centers were included and a total of 3,578 children between 13-14 years old were studied. The International Study of Asthma and allergy in Children (ISAAC) written and video questionnaires were used. Statistical analysis included bar diagrams, qualitative variable frequencies and the Chi 2 test to study the contrast and the association between variables. The statistical significance level was 95%. The relative risk according to sex was obtained. RESULTS: The questionnaires that were valid (3,213) represented 89% of the selected sample. The accumulated asthma prevalence was 18.9%. The actual asthma prevalence (asthma during the last year) was 11.9%. Severe asthma was present in 11.9% of the children. Asthma had been previously diagnosed in 16.3% of the children. The relative risk of being diagnosed was 1.39 for males. CONCLUSIONS: These figures are similar to those obtained in other populations with the same geographic and climate characteristics.