RESUMO
BACKGROUND AND AIM: The prevalence of childhood asthma varies among different nations and appears to have increased in recent years. It has been difficult to determine this prevalence precisely and compare the communities due to the lack of a standardized method. The International Studies of Asthma and Allergies in Childhood (ISAAC) has developed a written and video questionnaire to measure asthma prevalence and overcome these difficulties. This study was carried out to determine the prevalence of childhood asthma in Kashan, the central area of Iran, and to assess the agreement between the ISAAC written and video questionnaires and its gender relationship. METHODS: Between December 2002 and June 2003, 2533 school children, aged 13-14 years, in Kashan secondary schools completed sequentially the ISAAC written and video questionnaires. The agreement between responses to the two questionnaires for reported "ever wheeze", "exercise wheeze", "night wheeze" and "night cough" was determined, using kappa coefficient and concordance. RESULTS: The prevalence of asthma symptoms were significantly lower in the responses to the video questionnaire compared with the written questionnaire. Kappa coefficient showed only poor to fair agreement (kappa = 0.13-0.24) between video and written questionnaires, although the concordance between them always exceeded 60%. CONCLUSIONS: This study showed that reported asthma symptoms based on video questionnaires were significantly lower than the written questionnaire, and that there is low agreement between the two questionnaires which requires further investigation to explain the findings. In addition, this investigation revealed no significant difference between the genders for this low agreement.
