Fraction of Exhaled Nitric Oxide and Bronchial Responsiveness Are Associated and Continuous Traits in Young Children Independent of Asthma

Feno and bronchial responsiveness are associated and continuous traits in young children regardless of asthma symptoms, suggesting a continuous subclinical to clinical process underlying asthma. The findings also suggest caution against the use of these surrogate markers for a dichotomized approach to asthma diagnosis.