Validation of the ISAAC video questionnaire (AVQ3.0) in adolescents from amixed ethnic background

Background The International Study of Asthma and Allergies in Childhood (IS AAC) has developed an international version of the asthma video questionnai re (AVQ3.0) to measure asthma prevalence. This questionnaire has not been v alidated in adolescents from a mixed ethnic background. Objective The aims of this study were to compare the video questionnaire wi th a written questionnaire in the detection of airway hyperresponsiveness t o hypertonic saline in a population of adolescents from a mixed ethnic back ground, and to establish the repeatability and psychometric properties of t he asthma video questionnaire. Methods The study was conducted in four secondary schools in Sydney, an are a with a high proportion of people from a non-English speaking background. Four hundred and seventy-five students from schools 1 and 2 completed the v ideo questionnaire and a subgroup of these students (n = 170) completed the written questionnaire and a hypertonic saline inhalation challenge. Reprod ucibility of the questionnaire was evaluated by administering the questionn aire to a subsample of students 2 weeks later. The psychometric properties of the video questionnaire were examined in 852 students at two other schoo ls (schools 3 and 4). Results One hundred and sixty-nine students aged 13.5 (sd 1.3) years comple ted both written and video questionnaires, and the hypertonic saline challe nge. The students had widely different cultural backgrounds including Asian , South Pacific, Middle Eastern, European and African countries. There was good agreement between the questionnaires for wheeze (kappa 0.42). Question s on the video questionnaire concerning wheezing had good sensitivity (90%) and specificity (68%) for airway hyperresponsiveness to hypertonic saline. The video questionnaire was reproducible (kappa 0.82), had good internal c onsistency (Cronbach's alpha 0.81) and each question pertained to a single construct explaining 58% of the variance in total score. Conclusion This study has validated the international version of the ISAAC video questionnaire against airway hyperresponsiveness to hypertonic saline in adolescents from a mixed ethnic background, and identified that the que stionnaire has good psychometric properties. The ISAAC video has proved to be a valuable tool for the assessment of asthma prevalence in populations o f ethnic diversity.