Background: Non-specific nasal and bronchial reactivity are frequently correlated in disease (rhinitis and asthma). It is not known whether such a correlation exists in subjects exposed to irritants and in healthy subjects. In order to test the hypothesis that a correlation between non-specific nasal and bronchial reactivity exists in non-asthmatic subjects, two groups of subjects were studied: 110 workers occupationally exposed to respiratory irritants, and 86 non-exposed healthy controls.
Methods: Allergy, non-specific nasal, and non-specific bronchial reactivity were tested, and smoking habits were categorized in each subject.
Results: Respiratory irritants cause a substantial increase in nasal and bronchial reactivity when compared with the group of healthy, non-exposed subjects (33.6% nasal hyperreactors and 20.0% bronchial hyperreactors vs. 4.7% nasal hyperreactors and 2.3% bronchial hyperreactors, respectively). But, occupational exposure to respiratory irritants does not induce a correlation between non-specific nasal and bronchial reactivity frequently found in asthmatic and rhinitic subjects.
Conclusions: We found no correlation between non-specific nasal and bronchial reactivity either in subjects occupationally exposed to respiratory irritants or in the group of healthy subjects. This lack of correlation in both studied groups seems to be a feature of non-diseased airways. Smoking as an additional factor does not increase nasal and bronchial reactivity either in workers exposed to irritants or in healthy subjects. Smoking also does not strengthen the correlation between upper and lower airways' reactivity in both groups.