摘要
Abstract
Objectives The aim of this study was to establish FeNO reference values for healthy school-aged children in Suzhou according to the international guidelines, and to assess the determinants of FeNO. Methods Children aged 6-14 years were recruited from two public schools in Suzhou. The subjects completed a respiratory questionnaire, and were examined with measurements of FeNO, spirometry and blood eosinophil. Healthy children were screened to establish reference values of FeNO. FeNO was measured with a chemiluminescence analyzer according to American Thoracic Society guidelines ( single breath online, exhalation flow 50 mL · s-1 ). The associations between different determinants ( sex, age, height, weight, BMI, peripheral blood EOS count, FEV1/FVC, lung function) and FeNO were analyzed. Results Finally, a total of 450 children participated in the study, and 225 children fulfilled the inclusion criteria of healthy subjects ( 107 boys and 118 girls ). FeNO data were skewed, and met normal distribution after natural logarithm transformation. The geometric mean of FeNO in 225 children was 11 parts per billion ( ppb ) ( 95% CI: 5-28 ppb ), the minimum value was below 5 ppb, and the maximum value was 83 ppb. The mean value was 11 ppb ( 95% CI:5 - 31 ppb ) for boys and 11 ppb ( 95% CI: 5 - 25 ppb ) for girls. In stepwise multiple regression analysis, peripheral blood EOS count was found to be the best independent variable for the regression equation for FeNO ( r =0. 291, P < 0. 000 1 ). Height ( r =0. 148, P =0. 027 ) and FEV1 ( r =0. 138 , P =0.038 ) were significantly correlated with FeNO. FeNO in children aged >9 years was significant higher than that in children aged ≤ 9 years( P =0. 002 ). Sex, weight, BMI and FEV1/ FVC were not associated with FeNO. Conclusions FeNO reference values of healthy children aged 6 to 14 years in Suzhou should be considered to fall between the following ranges: 5-28 ppb, which is slightly higher than European and American children. FeNO levels in healthy school-aged children appear to be affected by EOS count and height significantly, followed by FEV1, and not influenced by sex, age, weight, BMI and FEV1/FVC.关键词
呼出气一氧化氮/参考值/健康儿童/气道炎症Key words
Fractional exhaled nitric oxide/Reference values/Healthy children/Airway inflammation
