THE RELATIONSHIP BETWEEN RESPIRATORY SYMPTOMS AND BRONCHIAL HYPERRESPONSIVENESS IN A POPULATION-BASED SAMPLE OF ADOLESCENTS AND YOUNG-ADULTS

Objectives: to study the relationship between chronic respiratory symptoms and bronchial hyperresponsiveness (BHR) in adolescence and young adulthood and to assess the possible predictive value of these symptoms for BHR. Methods: a cross-sectional analysis: in a population sample of 551 subjects aged 10-23 years, data collected with a standardized questionnaire on respiratory symptoms were compared with the results of a histamine challenge test. Results: 43% of the subjects reported one or more chronic respiratory symptoms; of these subjects 54% did not show BHR. Forty-two per cent of the subjects had a PC20 less than or equal to 8.0 mg ml(-1) histamine, of which 53% reported no chronic respiratory symptoms. Wheezing and breathlessness were related to the level of BHR, but only 'breathless when walking on the flat' was independently related to BHR; however, its predicted value for BHR was negligible. Conclusions: in adolescents and young adults the relationship between chronic respiratory symptoms and BHR is incomplete. A standardized questionnaire on respiratory symptoms does not provide adequate information to discriminate between those with and without BHR.