Abstract
Our aim was to study the association of smoking habits and environmental tobacco smoke exposure (ETS) with bronchial hyperresponsiveness (BHR).
A random sample of 292 adults was examined with a structured interview, spirometry, skin prick tests, FeNO (fractional exhaled nitric oxide) and bronchial histamine challenge.
A large majority of subjects with BHR were smokers or ex-smokers. Starting to smoke before 20 years of age was significantly associated with BHR, as did current smoking, the quantity of smoking, and ETS. The severity of BHR increased significantly with increasing pack years (p<0.001). Current smokers with decreased lung function were at a particularly high risk for BHR. Impaired FEV1 and MEF50 were independent determinants for more severe BHR regardless of age. In multivariate analysis, smoking remained as an independent determinant for BHR after adjustment for impaired lung function and other co-variates: 15 or more pack years yielded an OR 3.00 (95%CI 1.33–6.76) for BHR. The association between BHR and FeNO was dependent on smoking habits.
The results indicate that smoking is a significant risk factor for BHR with a dose-dependent pattern and that the severity of BHR increases with pack years. The findings strongly suggest assessment of smoking habits in subjects with BHR.
- ERS