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20-02-2013 | Immunology | Article

Exhaled nitric oxide shows promise as childhood asthma predictor


Free abstract

medwireNews: High levels of exhaled nitric oxide (FeNO) in infancy predict asthma development in later childhood, show study findings.

The researchers hope their findings will support the use of exhaled FeNO testing as part of a noninvasive asthma predictive index (API), as the results showed comparable accuracy to the standard API that requires blood testing to measure eosininophilic counts.

Alexander Moeller (University Children's Hospital Zurich, Switzerland) and colleagues measured immunoglobulin (Ig)E levels, eosinophils, and exhaled FeNO in 391 children aged 3-47 months. Of these children, 166 were followed up at the age of 6 years or older to assess their respiratory health.

Of the 166 children who were assessed, 68 had developed asthma by the end of follow up (34 atopic; 36 treated with inhaled corticosteroids [ICSs]).

As reported in Allergy, median FeNO levels were significantly higher in exhaled breath samples from children who went on to develop asthma than in those who did not, at 10.5 versus 7.4 ppb.

ICS treatment at preschool age affected the association to a certain degree, as children who were ICS naïve and later developed asthma had even higher baseline FeNo levels, of 12.5 ppb, while a baseline average of 7.0 ppb was seen among those with later asthma who received preschool treatment with an ICS.

The team estimated that for each 5-ppb increase in exhaled FeNO at baseline, the risk for asthma in later childhood increased 2.44-fold. This association did not change significantly after adjusting for confounders, they note.

When exhaled FeNO was added to an API including factors such as parental asthma, presence of atopic eczema, and wheeze apart from colds, among others, it had a positive predictive value of 58.0% and a negative predictive value of 78.2%; similar values to those obtained using the standard API that includes blood eosinophils instead of exhaled FeNO.

"FeNO in preschool age may help to more reliably identify those children at risk for later asthma who would directly benefit from anti-inflammatory disease control," conclude Moeller and co-authors.

medwireNews ( is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2013

By Helen Albert, Senior medwireNews Reporter

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