QUESTIONNAIRE ITEMS THAT PREDICT ASTHMA AND OTHER RESPIRATORY CONDITIONS IN ADULTS

The International Union Against Tuberculosis and Lung Disease question naire is widely used in epidemiologic studies of adult asthma, We exam ined whether the symptom questions could be classified into groups tha t represent different ''syndromes,'' and whether some questions are be tter for predicting asthma than others. We analyzed questionnaire data from a population sample of 1,527 adults aged 18 to 55 years using fa ctor analyses to classify the 17 respiratory symptom questions into fo ur different groups that we termed asthma, cough, breathlessness, and urgent medical visit. The urgent medical visit was a subset of asthma. These four ''syndromes'' had good validity when measured against airw ay responsiveness to histamine, atopy to common allergens, lung functi on, smoking status, and body mass index. Questions that predicted asth ma syndrome were those that asked about wheeze at rest or following ex ercise, asthma attack, chest tightness, and shortness of breath at res t, Questions about cough identified a different group of subjects who apparently did not have asthma, Questions of breathlessness did not ag gregate with ''asthma'' or with ''cough syndrome.'' The identification of particular questions that measure different respiratory conditions is important for epidemiologic studies when short questionnaires or m ore precise definitions are required.