Association between caffeine intake and fractional exhaled nitric oxide (FENO) in asthmatic children: NHANES 2007-2012

Abstract

Background: Most studies explored the possible effects of caffeine on asthma and its symptoms in children, but the results were inconsistent. Few studies have investigated the association between caffeine and fractional exhaled nitric oxide (FENO). Therefore, we explored the association between caffeine intake and FENO in pediatric asthma patients by utilizing data from NHANES. Methods: A total of 928 asthmatic children were enrolled in our study after screening NHANES participants from 2007 to 2012. Linear regression model and XGBoost model were used to assess the potential association between caffeine intake and FENO in asthmatic children. Linear or nonlinear association was further confirmed with generalized additive model and piecewise linear regression model. We also executed stratified analyses to identify specific populations. Results: Multivariate linear regression models showed a negative correlation of caffeine intake with FENO in asthmatic children. Simultaneously, for each unit increase in caffeine intake (mg) FENO decreased by a certain amount, with 0.03 (-0.04,-0.02) ppb for model 1 which adjusted no covariates, 0.03 (-0.04,-0.01) ppb for model 2 which adjusted for sex, age, ethnicity, educational background, family income, and 0.03 (-0.05,-0.01) ppb for model 3 adjusted for BMI, waist, TC, TG, HDL based on model 2. Furthermore, we applied the XGBoost model of machine learning to assess the relative importance of chosen variables, and identified vitamin C, iron, caffeine intake, vitamin B12 and vitamin D as the five most significant variables for FENO. And the generalized additive model and the piecewise linear regression model further verified this linear and inverse association. Conclusion: Our study elucidated the linear and inverse relationship between caffeine intake and FENO in pediatric asthma patients, suggesting a potential immunological role of caffeine intake in asthmatic children. These findings pave the way for further research on the role of caffeine in the pathogenesis and treatment of asthma, and underscore the importance of recognizing the immunological implications of caffeine in asthma management.