Abstract
We assessed whether exhaled nitric oxide fraction (FeNO), a marker of eosinophilic airway inflammation, at 6 months was associated with the risk of wheezing during the first 2 yrs of life.In the Generation R birth cohort, pre- and post-natal risk factors for respiratory morbidity and respiratory symptoms were assessed by questionnaires at 6 and 24 months. In 428 infants, off-line mixed oral/nasal FeNO was successfully measured during tidal breathing at 6 months. Complete data on FeNO and respiratory symptoms within the first 6 months of life were available for 294 infants.FeNO was higher in males, was positively associated with age and was negatively associated with upper and lower respiratory symptoms within the first 6 months. Logistic regression analysis showed that for every ppb increase of FeNO measured at 6 months, infants had a 1.06 (95% confidence interval 1.01–1.11)-fold increased risk of wheezing in the second year of life. High FeNO (>17.5 ppb) showed a limited added value in predicting wheezing in the second year.We conclude that FeNO at 6 months is positively associated with the risk of wheezing, but has limited added value in predicting wheezing in the second year of life in individual children.