No abstract

A video questionnaire (VQ) for measuring asthma prevalence in adolescents was assessed for repeatability and validity in relation to bronchial hyperresponsiveness (BHR) (PD20 less than or equal to 7.8 mumol methacholine). Comparison was also made with a standard, self completed written questionnaire (SQ), based on the IUATLD Bronchial Symptoms Questionnaire, which included five questions seeking comparable data to those in the VQ. Both the VQ and SQ were administered to 707 schoolchildren (13-16 years), in whom English was the primary language. One hundred and six randomly selected children subsequently underwent bronchial challenge to methacholine. Both the sensitivity and specificity for BHR were higher for a combination of three or more positive responses to the VQ (0.73 and 0.88), than to the SQ (0.63 and 0.82), although these differences were not statistically significant (P = 0.24). When administered again after a two week interval, the VQ had a significantly higher (P = 0.03) coefficient of repeatability (0.79) than the SQ (0.50). We conclude that the VQ is a valid and reliable method of determining asthma prevalence, and propose that by providing data relatively free from biases due to language, culture, literacy or interviewing techniques it may be particularly useful when comparing asthma prevalence and severity in different populations.

To estimate the prevalence of respiratory symptoms, bronchial hyperresponsiveness, smoking, and atopy in a population of Australians of Aboriginal descent (AAD), to determine the association of these and other factors with lung function, and to compare levels of lung function of AAD with Australians of European descent (AED) according to age and height, and to explore reasons for their differences, we conducted a study of 96 male (41 of whom were under 18 yr of age) and 111 female (48 of whom were under 18 yr of age) AAD living in a single remote tropical community in 1993. This population provided data on age, height, and lung function. A modified British Medical Research Council (MRC) questionnaire on respiratory symptoms and smoking was administered. FEV1, FVC, height, age, and bronchial responsiveness to inhaled methacholine were measured. Atopic status was assessed by skin prick tests for eight common allergens. Age- and sex-adjusted lung function was similar to that of other AAD groups and lower than in AED. For children, lung function increased less with increasing height in AAD than in AED. Lung function was reduced in adult AAD as compared with adult AED, although it was not possible to determine statistically whether lung function started to decline at an earlier age or declined faster with increasing age in AAD. A history of asthma, smoking, dyspnea, cough, or sputum production; atopic status; and increased bronchial responsiveness were all associated with lower levels of lung function. Differences in lung function between AAD and AED appear to be determined by characteristics that may be inherited, as well as by adverse external influences.