Table of Contents
ISRN Allergy
Volume 2011, Article ID 792613, 6 pages
http://dx.doi.org/10.5402/2011/792613
Research Article

Subjects in a Population Study with High Levels of FENO Have Associated Eosinophil Airway Inflammation

1Departments of Allergology and Respiratory Medicine, Sahlgrenska University Hospital, 413 45 GΓΆteborg, Sweden
2Departments of Occupational and Environmental Medicine, Sahlgrenska University Hospital, 413 45 GΓΆteborg, Sweden

Received 16 December 2010; Accepted 19 January 2011

Academic Editors: S. Lau and S. Loukides

Copyright Β© 2011 Gerdt C. Riise et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background. Measurement of fraction of exhaled nitric oxide (FENO) is a promising tool to increase validity in epidemiological studies of asthma. The association between airway inflammation and FENO has, however, only been examined in clinical settings and may be biased by selection of patients with asthma. Methods. In a population study with FENO registrations on 370 individuals, we identified nine subjects out of thirty subjects with high levels of FENO (>85th percentile, 30.3 ppb), irrespective of presence of respiratory symptoms, and 21 control subjects with FENO at median levels (11.1–16.4 ppb) willing to undergo bronchoscopy and bronchoalveolar lavage (BAL), all nonsmokers. FENO was measured in accordance with ATS criteria, and the examination also included spirometry, methacholine challenge test, and sampling of exhaled breath condensate (EBC). Results. Subjects with high FENO levels had significantly higher median the percentage of eosinophils in BAL than controls (2.1 versus 0.6, 𝑃 < . 0 0 6 ), and there was a significant association between FENO and the percentage of eosinophils in BAL ( 𝜌 = 0 . 6 , 𝑃 < . 0 0 2 ) and ECP in BAL ( 𝜌 = 0 . 6 5 , 𝑃 < . 0 5 ) examining the whole group, but no association with gender, FEV1, or degree of metacholine sensitivity or any of the biomarkers in EBC. All subjects with high FENO had respiratory symptoms, but only three had diagnosed asthma. There were a significant association between hydrogen peroxide in EBC and the percentage of neutrophils in bronchial wash. Conclusion. High FENO levels signal asthmatic or allergic respiratory disease in a population-based study. FENO levels are associated with degree of eosinophil airway inflammation as measured by the percentage of eosinophils and ECP in BAL.