ASYMPTOMATIC BRONCHIAL HYPERRESPONSIVENESS IN ADOLESCENTS AND YOUNG-ADULTS

The clinical significance of asymptomatic bronchial hyperresponsivenes s (BHR) is not web-known. The aim of this study was to explore, in a c ross-sectional analysis, the characteristics of adolescent subjects wi th asymptomatic BHR, as compared to nonhyperresponsive subjects and th ose with symptomatic BHR. The subjects were selected by date of birth from the register of general practitioners. The hypothesis that both a symptomatic and symptomatic BHR are related to early childhood lower r espiratory tract infections was also tested, in a historical cohort an alysis. Respiratory morbidity was studied in early childhood and BHR i n adolescence and young adulthood, in a population of 551 subjects age d 10-23 yrs. Morbidity had been recorded prospectively since birth in the general practice. Data on chronic respiratory symptoms, smoking be haviour, airways obstruction, BHR and allergy were collected during th is investigation. BHR was present in 42% of the subjects, of which 70% were asymptomatic. The occurrence of symptomatic BHR was related to a cute bronchitis in early childhood, allergy, airways obstruction and r ecent asthma, acute bronchitis and hay fever; whereas, asymptomatic BH R was not. Characteristics of subjects with asymptomatic BHR did not d iffer significantly from those without BHR, with respect to these fact ors. We conclude that asymptomatic bronchial hyperresponsiveness in ad olescence and young adulthood is not related to lower respiratory infe ctions in early childhood. Furthermore, subjects with asymptomatic bro nchial hyperresponsiveness have similar characteristics to those witho ut bronchial hyperresponsiveness, but differ strongly from subjects wi th symptomatic hyperresponsiveness. Asymptomatic bronchial hyperrespon siveness may not be the link between early childhood lower respiratory morbidity and asthma in later life, nor a risk factor for later asthm a. (C)ERS Journals Ltd 1997.