Relationship between exhaled NO, respiratory symptoms, lung function, bronchial hyperresponsiveness, and blood eosinophilia in school children
- P A Steerenberg1,
- N A H Janssen4,
- G de Meer3,
- P H Fischer2,
- S Nierkens1,
- H van Loveren1,
- A Opperhuizen3,
- B Brunekreef4,
- J G C van Amsterdam3
- 1P A Steerenberg, S Nierkens, H van Loveren, Laboratory for Pathology and Immunobiology, National Institute of Public Health and the Environment, Bilthoven, The Netherlands
- 2P H Fischer, Department of Chronic Diseases and Environmental Epidemiology, National Institute of Public Health and the Environment
- 3A Opperhuizen, J G C van Amsterdam, Laboratory of Health Effects Research, National Institute of Public Health and the Environment
- 4N A H Janssen, G de Meer, B Brunekreef, Institute for Risk Assessment Sciences, Environmental & Occupational Health Division, Utrecht University, Utrecht, The Netherlands
- Correspondence to:
Dr P A Steerenberg, Laboratory for Pathology and Immunobiology, National Institute of Public Health and the Environment (RIVM), P O Box 1, 3720 BA Bilthoven, The Netherlands;
- Accepted 21 October 2002
- Revised 21 September 2002
Background: Exhaled nitric oxide (eNO) may serve as a non-invasive marker of airway inflammation but its relationship with other commonly used measures has not been evaluated.
Methods: Levels of eNO in a sample of 450 children aged 7–12 years out of a total sample of 2504 school children living in different urban areas near motorways were determined. The aim of this cross-sectional study was to explore the relationship between eNO, impairment of lung function (PEF, FVC, FEV1 and MMEF), bronchial hyperresponsiveness (BHR), and blood eosinophilia in children with and without atopy as assessed by skin prick testing.
Results: Regression analysis showed that wheezing and nasal discharge and conjunctivitis that had occurred during the previous 12 months were positively associated with eNO levels in atopic children (relative increase of 1.48 and 1.41, respectively; p<0.05) but not in non-atopic children. Similarly, BHR and the number of blood eosinophils per ml were positively associated with eNO levels in atopic children (relative increase of 1.55 and 2.29, respectively; p<0.05) but not in non-atopic children. The lung function indices PEF, FVC, FEV1 and MMEF were not associated with eNO levels.
Conclusions: In addition to conventional lung function tests and symptom questionnaires, eNO is a suitable measure of airway inflammation and its application may reinforce the power of epidemiological surveys on respiratory health.