ABSTRACT
BACKGROUND: Airway hyper-responsiveness (AHR) is a common feature in asthma. The use of AHR in predicting active asthma or the persistence of AHR in childhood is poorly understood. By analyzing longitudinal connections including different measures of AHR, lung function, and inflammation markers, we sought to identify the best available method for predicting persistence of AHR and identification of later active asthma. METHODS: We tested 105 asthmatic children aged 3-7 years with fractional exhaled nitric oxide (FeNO), impulse oscillometry (IOS), and AHR evaluated by indirect methods (hypertonic saline and exercise challenge). Ten years later, 64 children participated in the follow-up visit and were tested with FeNO, IOS, spirometry, and methacholine challenge. At both study visits, blood samples were collected, and a questionnaire was completed. RESULTS: Asthma was in remission in 66% of patients at adolescence. AHR measured by hypertonic saline challenge at preschool age was associated with asthma symptoms (OR 10.2; 95% CI 2.8, 37.3) but not with AHR estimated with methacholine challenge 10 years later. AHR measured by exercise challenge was not associated with AHR or recent asthma symptoms in adolescence. Preschool eosinophilia continued until adolescence in 87% of patients but was not associated with AHR or subjective signs of asthma 10 years later. Wheezy preschoolers with atopy had a higher risk for AHR in adolescence (OR 4.1; 95% CI 1.0, 16.2). CONCLUSION: Results from hypertonic saline challenge are associated with persistent asthma symptoms even after a decade. AHR measured by indirect methods at preschool age did not predict AHR in adolescence.
Subject(s)
Asthma/diagnosis , Respiratory Hypersensitivity/diagnosis , Adolescent , Breath Tests/methods , Bronchial Provocation Tests/methods , Child , Child, Preschool , Female , Humans , Longitudinal Studies , Male , Methacholine Chloride/therapeutic use , Nitric Oxide/therapeutic use , Prognosis , Respiratory Function Tests/methods , Respiratory Sounds/diagnosis , Spirometry/methods , Surveys and QuestionnairesABSTRACT
BACKGROUND: Asthma often begins early in childhood. However, the risk for persistence is challenging to evaluate. OBJECTIVE: This longitudinal study relates lung function assessed with impulse oscillometry (IOS) in preschool children to asthma in adolescence. METHODS: Lung function was measured with IOS in 255 children with asthma-like symptoms aged 4-7 years. Baseline measurements were followed by exercise challenge and bronchodilation tests. At age 12-16 years, 121 children participated in the follow-up visit, when lung function was assessed with spirometry, followed by a bronchodilation test. Asthma symptoms and medication were recorded by a questionnaire and atopy defined by skin prick tests. RESULTS: Abnormal baseline values in preschool IOS were significantly associated with low lung function, the need for asthma medication, and asthma symptoms in adolescence. Preschool abnormal R5 at baseline (z-score ≥1.645 SD) showed 9.2 odds ratio (95%CI 2.7;31.7) for abnormal FEV1/FVC, use of asthma medication in adolescence, and 9.9 odds ratio (95%CI 2.9;34.4) for asthma symptoms. Positive exercise challenge and modified asthma-predictive index at preschool age predicted asthma symptoms and the need for asthma medication, but not abnormal lung function at teenage. CONCLUSION: Abnormal preschool IOS is associated with asthma and poor lung function in adolescence and might be utilised for identification of asthma persistence.
