Association between fractional exhaled nitric oxide (FeNO) and blood eosinophil count among children and adolescents with asthma in the United States: a population-based study.

OBJECTIVE

The association between FeNO and blood eosinophil count among children and adolescents with asthma in the United States was investigated using data from the National Health and Nutrition Examination Survey (NHANES) 2007-2012.

METHODS

A total of 934 children and adolescents with asthma aged 7-19 years were included in the analysis. Multivariate linear regression, smooth curve fitting, threshold effect analysis, and subgroup analyses were performed to evaluate the association between FeNO and blood eosinophil count.

RESULTS

After adjustment for covariates, each one-unit increase in blood eosinophil count was associated with a 5.34 ppb increase in FeNO among children and adolescents with asthma (β = 5.34, 95 % CI: 4.16-6.52). Moreover, FeNO and blood eosinophil count demonstrated a nonlinear relationship pattern, with evidence suggesting a change in the slope at higher blood eosinophil counts. Subgroup analyses revealed significant interactions across age, sex, race/ethnicity, and body mass index (BMI).

CONCLUSIONS

This population-based study demonstrated a significant positive association between FeNO and blood eosinophil count among children and adolescents with asthma in the United States.