Self-reported race and ethnicity affect FeNO values in healthy individuals

Abstract

Background: Race and ethnicity are known factors of variation in pulmonary function. We aim to determine if self-identified race/ethnicity affect the values of exhaled nitric oxide (FeNO) in healthy and asthmatic individuals in a population setting.

Methods: We analyzed the valid FeNO measurements (NIOX MINO) recorded in the National Health and Nutrition Examination Survey 2007-10 (n=13,275; age 6-79 years). Race/ethnicity is coded as Mexican American (20%), Other Hispanic (11%), Non-Hispanic White (43%), Non-Hispanic Black (20%) and Other Race - Inc. Multi-Racial (5%). Adjustments were made using multiple-linear regression models.

Results: Non-Hispanic Whites have the lowest FeNO values (mean 15.8 ppb, 95%CI 15.4; 16.1) and Other Race - Including Multi-Racial the highest (20.0 ppb (18.6; 21.4)). Race and ethnicity significantly affect FeNO values even after adjusting for age, gender, BMI and reported hay fever in non-asthmatic subjects (B=0.30, p=0.01), but not in individuals with self-reported asthma (B=0.09, p=0.83). However, the mean difference between race/ethnicity categories was reduced after excluding subjects with hay fever.

Conclusion: Race and ethnicity are significant factors for FeNO in healthy individuals. Hay fever seems to play an important role in the mean difference between race/ethnicity categories. An objective measurement of atopy is probably needed to clarify this relationship.