Normal values and influencing factors of fractional exhaled nitric oxide for Chinese healthy adults

Abstract

To evaluate the normal values of fractional exhaled nitric oxide (FENO) for Chinese adults. A total of 200 non-smoking and healthy Chinese adults were recruited according to the inclusion and exclusion criteria. They received lung function and allergen skin prick tests at the Outpatient Department of China-Japan Friendship Hospital from February to August 2011. There were 100 males and 100 females. FENO test was performed according to the standard procedures of American Thoracic Society/European Respiratory Society (ATS/ERS) recommendation. The FENO levels of healthy non-smokers were tested by the NIOXMINO analyzer. All variables, such as age, gender, height, weight, forced expiratory volume at 1 second (FEV(1))% predicted and FEV(1)/FVC, were included for multiple regression analyses. The FENO level of healthy non-smokers was (14.2 ± 5.6)×10(-9) mol/L with the 95% normal range of (3.2 - 25.2)×10(-9) mol/L. The value of FENO was significantly higher in males than females ((15.6 ± 5.5) vs (12.9 ± 5.4)×10(-9) mol/L, t = 3.48, P = 0.001). The FENO level of the subjects aged 60 - 80 years was (15.7 ± 5.4)×10(-9) mol/L and it was higher than those aged 18 - 60 years ((13.8 ± 5.6)×10(-9) mol/L, t = 2.04, P = 0.040). Multiple regression analysis showed that gender was an independent influencing factor of FENO level. The FENO level of non-smoking and healthy Chinese adults is similar with that of the westerners. Gender is an independent influencing factor of FENO level.