Reference values of the fraction of nitric oxide in exhaled breath from healthy young adults in Korea

Abstract

The measurement of nitric oxide (NO) in exhaled air provide the activity of airway inflammation and used as a marker of airway inflammation in respiratory diseases, such as asthma. Reference values of the fraction of NO in exhaled breath (FeNO) in normal population are not well defined yet. This study is to establish reference value of FeNO for adult population without respiratory diseases and to determine which factors are related with the levels of FeNO. Fifty six medical students, aged between 23 and 32, were enrolled for this study and evaluated for smoking status and asthma by a questionnaire. FeNO was measured using a NO analyzer (NOA280; Bouler, Co, USA) according to the recommendations by ATS and ERS. Spirometry, skin prick test to common aeroallergens and methacholine bronchial provocation test was performed. Levels of FeNO in the study subjects ranged from 11.5 to 96.8 ppb and geographic mean was 28.6 ppb. Smoking affected levels of NO significantly, while sex and atopy did not show significant association. The reference range from young adults in Korea will help interpret levels of FeNO in patients with airway inflammation.