Background: The ISAAC (International Study of Asthma and Allergies in Childhood) was thought in order to maximize the value of epidemiological research into asthma and allergic diseases in childhood, establishing a standardized methodology and facilitating collaboration and comparison between several countries.
Methods and results: The written questionnaires in the group of children aged 6-7 years was answered by the parents and the group of children aged 13-14 years self-completed the written questionnaires.
Results: 3,040 children aged 13-14 years answered the questionnaire and 3,002 in the group aged 6-7 years. In the group of children aged 13-14, 49.7% referred rhinitis symptoms some time, and 15.6% in the 6-7 year old group. The prevalence of nasal symptoms in the last year was 35.5% in the 13-14 year group and 10.6% in the 6-7 year group. The presence of nasal symptoms was more frequent in winter. The prevalence of seasonal allergic rhinitis (hay fever) was 6.1% in the 13-14 year group and 4.8% in the group of children aged 6-7 years.
Conclusions: These results can contribute to a better control of some factors and to future studies where the etiology and incidence of the disease could be investigated.