Abstract
Background: A high fractional nitric oxide concentration in exhaled breath (FeNO) is thought to be a marker of ongoing airway inflammation and may reflect poor asthma control.
Objectives: To study factors associated with high FeNO in children using asthma medication.
Methods: Our study population consists of 602 children (age 4-12 years) who used asthma medication in the past year and participated in the PACMAN (Pharmacogenetics of Asthma medication in Children: Medication with ANti-inflammatory effects)-cohort study. FeNO was measured using an electrochemical hand-held device (Niox Mino, Aerocrine, Sweden). Data on respiratory symptoms, medication use, therapy adherence and environmental factors were collected using a questionnaire. Asthma control was defined using the Asthma Control Questionnaire (ACQ). Children with high FeNO (>25 ppb) were compared to children with normal FeNO (5-25 pbb). Logistic regression analysis was used to study factors associated with high FeNO.
Results: FeNO could be measured in 501 children (83%); FeNO was high in 134 children (27%). Children with high FeNO were older than children with normal FeNO (mean age: 9.8 vs 8.7 years, p<0.01). In addition, high FeNO was associated with a lower chance of good adherence to asthma medication (OR: 0.4; 95%CI 0.2-0.6) and a lower chance of well-controlled asthma according to the ACQ (OR 0.5; 95%CI 0.4-0.8).
Conclusions: In our cohort of children using asthma medication, high FeNO is associated with higher age, lower adherence and less well-controlled asthma at population level. Further research is necessary to assess the value of FeNO for the individual patient.
- © 2011 ERS
