A study of normal values of exhaled nitric oxide in children aged 6 to 18 years in Jinan / 中华实用儿科临床杂志

ABSTRACT

Objective:To investigate the normal range of exhaled nitric oxide in healthy children aged 6-18 in Jinan.Methods:The healthy school children aged 6-18 in Jinan from October 11 to 26, 2017 were selected for questionnaire survey, physical examination and exhaled nitric oxide test.The levels of mouth exhaled nitric oxide at the flow rate of 50 mL/s (FeNO 50) and mouth exhaled nitric oxide at the flow rate of 200 mL/s(FeNO 200), alveolar nitric oxide (CaNO), and nasal exhaled nitric oxide at the flow rate of 10 mL/s(FnNO 10) were measured by the electroche-mical method.The distributions of FeNO 50, FeNO 200, CaNO and FnNO 10 were analyzed, and their correlations with gender, age, height and body mass index (BMI) were discussed by the multiple linear regression model. Results:A total of 772 healthy children were enrolled in this study, including 364 males and 408 females, with a median age of 12.1(11.8-12.3) years old, a median height of 154.8(153.6-156.0) cm, and a median BMI of 20.3 (20.0-20.6) kg/m 2. The measured values of FeNO 50, FeNO 200, CaNO and FnNO 10 fluctuated in the range of 3.0-168.0 ppb, 2.0-44.0 ppb, 0.5-44.2 ppb and 0-1 253.0 ppb, respectively.FeNO 50, FeNO 200 and CaNO values showed skewed a distribution, and their 95% upper limits were 35.0 ppb, 13.3 ppb and 8.5 ppb, respectively.The geometric mean(95% CI) of FeNO 50 in males (95% CI)[14.6 (13.7-15.5) ppb] was significantly higher than that in females [13.3(12.7-14.0) ppb], and the difference was statistically significant ( Z=1.470, P=0.027). The multiple linear regression results suggested that, FeNO 50 was positively correlated with age and height ( β=0.023, 0.007, respectively, all P<0.05), and negatively correlated with BMI ( β=-0.016, P<0.05). The geometric mean (95% CI) of FeNO 200in males[7.1 (6.8-7.4) ppb] was significantly higher than that in females[6.4 (6.1-6.6) ppb], and the difference was statistically significant( Z=1.747, P=0.004). The multiple linear regression results suggested that, FeNO 200 was positively correlated with height ( β=0.005) and negatively correlated with gender(female β=-1.126) (all P<0.05). There was no significant difference between male and female in CaNO, which had no correlation with gender, age, height and BMI (all P>0.05). FnNO 10 showed a normal distribution, with a mean value of 456.2 ppb, 95% CI of 29.3-863.4 ppb.The geometric mean (95% CI) of FnNO 10 in males [408.7 (377.1-443.0) ppb] was significantly higher than that in females [368.8 (339.0-401.3) ppb], and the difference was statistically significant ( Z=1.722, P=0.005). The multiple linear regression results indicated that FnNO 10 was related to gender ( β=-36.098, P<0.05), and not correlated with age, height and BMI (all P>0.05). Conclusions:The normal ranges of FeNO 50, FeNO 200, CaNO and FnNO 10 in healthy children aged 6-18 in Jinan are 3.0-35.0 ppb, 2.0-13.3 ppb, 0.5~8.5 ppb and 29.3-863.4 ppb, respectively.FeNO 50 is correlated with age, height and BMI.FeNO 200 is correlated with gender and height.CaNO and FnNO 10 are not correlated with age, height or BMI.