Active smoking by adults deteriorates asthma symptoms and pulmonary function and also increases bronchial responsiveness, but evidences from studies on adolescents are scare.
Methods
We conducted a cross-sectional survey of 1,492 adolescents that involved questionnaires and urinary cotinine levels in 3 urban areas of South Korea. Active smoking was defined as smoking more than 20 cigarettes during last month or urinary cotinine >40 ng/ml. Spirometry, allergy skin test, a bronchial challenge test were done for subpopulation (n = 724, mean age 15.7 yrs, girls 23.2%).
Results
The prevalence of active smoking was 9.0% in boys and 1.8% in girls. Active smoking was found to be significantly related with the prevalence of current wheeze, ever wheeze and current exercise-induced wheeze. In subgroup analysis, FEV1/FVC in active smokers was lower than nonsmokers (p = 0.027). Urinary cotinine showed negative correlation with serum IgE (r = −0.290, p = 0.032) and positive correlation with PC20 (r = 0.259, p = 0.056) among those who reported wheeze during the last 12 months. In a multiple logistic regression model, active smoking was a significant risk factor for wheeze ever (OR = 2.023, 95% CI 1.222-3.348). Active smoking in non-atopic subjects was associated with increased prevalence of current wheezing (OR = 4.02, 95% CI 1.417-11.407), current exercise-induced wheezing (OR = 23.120, 95% CI 2.074-257.7) and current asthma treatment (OR = 5.424 95% CI 2.100-14.007).
Conclusions
Active smoking may be associated with current wheeze, current exercise-induced wheeze and deterioration of pulmonary function in Korean adolescent population. Active smoking in non-atopic subjects may play a role in the development of asthma symptom.
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