School environmental factors are predictive for exercise-induced symptoms in children.

BACKGROUND: Environmental factors in schools have a significant effect on the exercise-induced bronchoconstriction and symptoms in a general paediatric population. OBJECTIVES: To determine the environmental factors such as atmospheric conditions and the presence of allergens in gymnasiums, that could be predictive of the presence of exercise-induced symptoms/bronchospasm in children during physical education (PE). METHODS: 1370 schoolchildren were enrolled. Children attended 45 min PE lesson with similar exercise intensity. Pulmonary function tests were performed before and after PE lesson. Air temperature, humidity and pressure, samples of dust for allergen exposure in the gymnasiums were taken. Children who reported symptoms induced during PE lesson were invited to the clinic for ETC (exercise treadmill challenge) and atopy measurement. RESULTS: 1033 participants were included into the analysis. Sixty seven(6.5%) children reported dyspnea/cough, and in 94(9.4%) children bronchoconstriction induced during PE lesson was documented. There is a correlation between the results of the ETC and bronchoconstriction after PE (OR: 2.55; 95%CI: 1.07-6.05; p = 0.034). Exposure to higher air pressure and higher humidity independently increase the risk of clinical symptoms reported during or after PE lesson. Exposure to cat's allergens increase the risk of bronchoconstriction (independently from atopy status). We showed significant interaction between presence of asthma and current ICS therapy as a risk of physical inactivity at school (OR: 4; 95%CI: 1.3-12; p < 0.001). CONCLUSION: This study showed an effect of cat allergen and environmental factors (humidity, air pressure) on the appearance of exercise related cough/bronchoconstriction during activity class in a natural environment at school in a large urban population of schoolchildren.

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.

Airway response to exercise measured by area under the expiratory flow-volume curve in children with asthma.

BACKGROUND: The exercise challenge test is the gold standard for diagnosing exercise-induced bronchoconstriction; however, it produces negative results in many children with postexercise symptoms. OBJECTIVE: To assess the utility of the area under the expiratory flow-volume curve (Aex) to identify exercise-induced bronchoconstriction in children with asthma. METHODS: Data from the medical records of 221 children with asthma who underwent an exercise treadmill challenge (ETC) were analyzed. The relation between exercise-induced respiratory symptoms and results of the ETC were assessed, specifically, the maximal decrease in forced expiration in 1 second (FEV1) and the maximal decrease in the Aex. RESULTS: The receiver operating characteristic curve showed that a decrease greater than 6% in the Aex was an optimal cutoff point to produce the fewest misclassified ETC results based on a greater than 10% decrease in FEV1. The results of multivariable logistic regression showed that a decrease greater than 6% in the Aex was comparable to a decrease greater than 10% in FEV1 during an ETC and was more closely related to the presence of exercise-induced respiratory symptoms. Measuring the Aex during a routine ETC allowed a confirmation of bronchoconstriction in an additional 49 children (44%) with asthma and exercise-induced respiratory symptoms. The Aex measurement increased the sensitivity and negative predictive value of ETC without a significant effect on ETC specificity. CONCLUSION: Measuring the Aex increases the sensitivity and negative predictive value of ETC without producing a significant change in ETC specificity. Applying a 6% decrease in the Aex as a cutoff point for a positive exercise challenge test result may prevent the underdiagnosis of exercise-induced bronchoconstriction in children with asthma and postexercise symptoms. TRIAL REGISTRATION: This study was registered at www.clinicaltrials.gov (NCT01798823).

The association between fractional exhaled nitric oxide (FeNO) and cat dander in asthmatic children.

BACKGROUND: The aim of our study was to assess risk factors of increased FeNO in asthmatic children with no cat at home. METHODS: It was a retrospective, cross-sectional study. We evaluated data from medical documentation of children with asthma: FeNO results, allergen sensitization, seasonal allergen exposure, FEV(1), allergic rhinitis (AR) diagnosis and cat presence at home. We assessed asthma severity using mean doses of inhaled glucocorticosteroids and a management approach based on control according to the newest guidelines of Global Initiative for Asthma (GINA) throughout the last three months before the measurement of FeNO and spirometry. RESULTS: 316 patients (age 6-18) completed the study. Sensitization to cat dander was associated with the highest median value of FeNO concentration compared to other allergens in our patients (28,4ppb) and co-existing sensitization did not affect FeNO level. Median levels of FeNO increased linearly with patient's age. In asthmatics with AR, the levels of FeNO were increased significantly compared to asthmatics without AR (20.8 vs. 16.3, respectively). We showed that in patients without AR, sensitization to cat allergen was associated with more severe asthma in comparison to other perennial allergy (step 4 vs. other steps according to GINA treatment steps). The above relation was not observed in patients with AR. We did not observe correlation between allergy profile and FEV(1) among patients in neither subgroup nor in general population. CONCLUSIONS: We revealed that sensitization to cat dander was associated with the highest increase of FeNO concentration compared to other allergens in patients not having any cat at home ever. We also observed that in patients without allergic rhinitis, sensitization to cat allergen, compared to other perennial allergy, was associated with more severe asthma.