The importance of atopy on exhaled nitric oxide levels in African American children

Abstract

BackgroundFor physicians to be maximally effective in managing asthma in minority populations, a better understanding of the factors that affect fractional exhaled nitric oxide (FeNO) measurements in African Americans is needed. ObjectiveTo examine demographic, environmental, and physiologic factors that influence FeNO measurements in African American children with and without asthma. MethodsA cross-sectional study of 128 African American children aged 7 to 18 years (44% with asthma) was conducted. FeNO measurements, skin prick tests (as a measure of atopy), spirometry, and questionnaire data were obtained from all participants. Regression models were constructed after identifying factors significantly associated on univariate analysis. ResultsAmong all study participants, the mean FeNO measurement at baseline was 24.4 ppb. Children with asthma had a higher level than those without (30.9 vs 19.3 ppb, P = .002). When examining all children through logistic regression analysis, an elevated FeNO level was significantly associated with atopy, lower spirometric values, and current asthma (P < .05 for all). Among asthmatic children, univariate analysis revealed that an elevated FeNO level was associated with inhaled corticosteroid use, recent respiratory infection, and atopy (P < .05 for all). However, only atopy remained significant after regression analysis. For asthmatic and nonasthmatic children, FeNO levels were directly correlated with the number of positive skin test results. ConclusionIn African American children with and without asthma, FeNO levels are strongly influenced by atopy. Guidelines for FeNO measurements that incorporate atopic status are needed.