Prevalence of exercise-induced cough in schoolchildren: a pilot study.

Association between exercise-induced bronchoconstriction (EIB) and physical activity has not been investigated in a natural school environment in a general pediatric population. Our objective was to determine the prevalence of exercise-induced symptoms (cough, wheeze, chest tightness, dyspnea) and bronchospasm among schoolchildren during physical education (PE). A total of 557 schoolchildren from seven public schools were enrolled. Information regarding demographic characteristic, previously diagnosed asthma was obtained. All children attended 45-minute PE lesson with similar exercise intensity. Pulmonary function tests were performed before and immediately after PE lesson. The diagnosis of EIB was defined as a forced expiratory volume in one second (FEV1) decrease from baseline of more than or equal to 10% with exercise. Cough and dyspnea after exercise were recorded. A total of 557 participants were included into the analysis. After PE lesson, 15.3% children suffered from cough, 0.9% reported dyspnea, and 10.1% had more than 10% fall in FEV1 from baseline. Among all participants, 5.9% had doctors' diagnosed asthma, 4.8% of them were treated with inhaled corticosteroids (ICS). Among children with cough, 21.5% had asthma and 17.6% experienced EIB. Among asthmatics, 48.6% suffered from cough and 18.2% had more than 10% fall in FEV1 from baseline after PE lesson. EIB was not affected by age, gender, body mass index, asthma diagnosis, and ICS use. Only cough (odds ratio: 2.21, 95% confidence interval: 1.16-4.23; p = 0.0161) was independently associated with EIB. This study showed a high prevalence of exercise-induced cough and/or 10% fall in FEV1 during activity lesson in a natural school environment in a large urban population of schoolchildren. Our results call for another studies addressing the impact of environment on exercise-induced symptoms.