Abstract
Objective: Fractional concentration of exhaled nitric oxide (FeNO) is a known marker of airway inflammation. The aims of this study were to evaluate FeNO, impulse oscillometry (IOS), and spirometry in preschool children and to investigate their relationship with wheeze and airway hyperresponsiveness (AHR). Methods: We performed a population-based, cross-sectional study with 561 children aged 5–6 years. A total of 544 children completed a modified International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire and eligible for the study. We measured FeNO, spirometry, methacholine bronchial provocation, and IOS. AHR was defined as the induction of a 20% decrease in FEV1(PC20) by a methacholine concentration ≤8.0 mg/dL. Results: Children who had wheeze or AHR had higher FeNO levels than children without these symptoms. However, neither IOS nor spirometry parameters showed significant differences between children with wheeze or AHR and those without. FeNO was associated with AHR, whereas IOS or spirometry parameters showed no association. Mean FeNO levels were positively correlated with a dose–response slope for methacholine, but neither IOS nor spirometry parameters showed significant correlations. Conclusions: FeNO is a more sensitive measurement of AHR and wheeze than spirometry or IOS in preschool children.
Acknowledgements
The authors are grateful to Phadia Korea for kindly providing us with the NIOX MINO device and technical support.
Declaration of interest
The authors report that they have no conflicts of interest. The authors alone are responsible for the content and writing of the paper. This study was supported by a grant from the Korea Healthcare Technology R&D Project, Ministry for Health, Welfare, Republic of Korea (A092076).