Impact of airway lability, atopy, and tobacco smoking on the development of asthma-like symptoms in asymptomatic teenagers - The odense schoolchild study

Aim: To investigate the impact of airway lability, atopy, and tobacco smoki ng on the development of asthma-like symptoms in asymptomatic subjects. Methods: In this prospective, community-based study, 271 asymptomatic adole scents with an average age at inclusion of 13.9 years were followed for 6.4 years. Airway lability was assessed at baseline by three tests, including exercise challenge, airway provocation with methacholine, and monitoring of peak expiratory flow. Atopy was defined by one or more positive reactions (greater than or equal to 3-mm weal) to 10 common aeroallergens by skin pri ck testing, The influence of airway lability, atopy, and smoking on the dev elopment of asthma-like symptoms was assessed by logistic regression. Results: During the 6-year study period, 68 of the previously asymptomatic teenagers (25%) developed asthma-like symptoms. Among those, 50% reported c ough only, 29% reported wheezing only, and 21% reported both wheezing and c oughing. Hyperresponsiveness to methacholine (odds ratio [OR], 3.5; 95% con fidence interval [CI], 1.1 to 11.6), smoking (OR, 2.1; 95% CI, 1.2 to 3.8), and atopy (OR, 3.5; 95% CI, 1.8 to 6.8) each contributed independently to explain symptom development (wheezing and cough together). Girls, but not b oys, with airway lability were less likely to take up smoking, compared wit h subjects of that set with no airway lability (32% vs 51%; p < 0.05). No e ffect of airway lability on the likelihood of giving up smoking could be de monstrated, nor did the presence of atopy have any significant impact on sm oking behavior. Conclusion: Hyperresponsiveness to methacholine, atopy, and smoking were in dependent risk factors for the development of asthma-like symptoms during a dolescence. The presence of airway lability may prevent girls from taking u p smoking.