COPSAC (Copenhagen Prospective Studies on Asthma in Childhood), Herlev and Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark.
COPSAC (Copenhagen Prospective Studies on Asthma in Childhood), Herlev and Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark.
J Allergy Clin Immunol Pract. 2018 May-Jun;6(3):855-862.e2. doi: 10.1016/j.jaip.2017.10.014. Epub 2017 Nov 10.
Exercise testing is the gold standard for diagnosing exercise-induced bronchoconstriction in children, but requires considerable cooperation and medical resources. Therefore, fraction of exhaled nitric oxide (FeNO) has been proposed as a tool to predict the need for exercise testing.
The objective of this study was to investigate the relationship between FeNO, exercise test results, and a history of respiratory symptoms during exercise in children at risk of asthma.
FeNO measurement, exercise testing, and interview about respiratory symptoms during exercise were completed in 224 seven-year-old children from the at-risk Copenhagen Prospective Studies on Asthma in Childhood birth cohort. The associations between FeNO, exercise test results, and reported respiratory symptoms during exercise were analyzed adjusting for gender, respiratory infections, and inhaled corticosteroid treatment. The associations were also analyzed stratified by asthma and atopic status.
Of the 224 children, 28 (13%) had an established asthma diagnosis and 58 (26%) had a positive exercise test (≥15% drop in forced expiratory volume in 1 second [FEV] from baseline). FeNO and bronchial obstruction after exercise were linearly associated with a doubling of FeNO corresponding to a 2.4% drop in FEV (95% confidence interval, 0.8-4.1; P < .01). However, a receiver operating characteristic curve analysis showed that the best cutoff of FeNO for predicting exercise test outcome among children who reported respiratory symptoms during exercise was 17 ppb, which only had 74% negative predictive value. There was no association between FeNO and reported respiratory symptoms during exercise (odds ratio = 1.3 [0.8-1.9]; P = .29) or reported symptoms during exercise and exercise test results (odds ratio = 1.0 [1.0-1.1]; P = .12).
A history of respiratory symptoms during exercise was not associated with either elevated FeNO or a positive exercise test in children at risk of asthma. FeNO and exercise test results were linearly associated traits, but FeNO could not reliably be used dichotomized to predict the need of exercise testing.
运动试验是诊断儿童运动诱发支气管收缩的金标准，但需要相当的配合和医疗资源。因此，呼气中一氧化氮分数（FeNO）已被提议作为预测运动试验需求的工具。
本研究旨在探讨有哮喘风险的儿童中 FeNO、运动试验结果和运动时呼吸症状史之间的关系。
在来自有哮喘风险的哥本哈根儿童哮喘前瞻性研究队列的 224 名 7 岁儿童中完成了 FeNO 测量、运动试验和运动时呼吸症状的访谈。在调整性别、呼吸道感染和吸入皮质类固醇治疗后，分析了 FeNO、运动试验结果和报告的运动时呼吸症状之间的关系。还按哮喘和特应性状态进行了分层分析。
在 224 名儿童中，28 名（13%）有确诊的哮喘，58 名（26%）有阳性运动试验（FEV1 从基线下降≥15%）。FeNO 和运动后气道阻塞与 FeNO 增加两倍呈线性相关，相应的 FEV1 下降 2.4%（95%置信区间，0.8-4.1；P<.01）。然而，接受者操作特征曲线分析显示，在报告运动时呼吸症状的儿童中，预测运动试验结果的最佳 FeNO 截断值为 17 ppb，其阴性预测值仅为 74%。FeNO 与运动时报告的呼吸症状之间无关联（比值比=1.3[0.8-1.9]；P=.29），也与报告的运动时症状和运动试验结果之间无关联（比值比=1.0[1.0-1.1]；P=.12）。
运动时呼吸症状的既往史与哮喘风险儿童的高 FeNO 或阳性运动试验均无关。FeNO 和运动试验结果呈线性相关特征，但不能将 FeNO 二分法可靠地用于预测运动试验的需求。
