Exhaled nitric oxide in a population sample of adults

Abstract

Background: The relationship between exhaled nitric oxide (FENO) and the diagnosis of asthma in the general adult population is not completely clear.

Objectives: To investigate the association between FENO and asthma, after controlling for atopy and rhinitis, in a general population sample of adults (mean age 43 years).

Methods: The cohort of subjects was a sample of subjects who gave their consent to participate in the European Community Respiratory Health Survey II study.

Results: Atopy, rhinitis and current asthma were positively and current smoking was negatively associated with FENO. Multivariate analysis showed that asthma had a significant predictive effect on FENO (beta = 0.53; 95% CI 0.21-0.84, p = 0.001), and the increase in FENO was significantly associated with the risk of current asthma (OR = 1.07, 95% CI 1.00-1.14) by the logistic regression model. Receiver-operator characteristic curve showed that FENO >or=18.5 ppb had the best combination of sensitivity (69.2%) and specificity (71%), with a positive predictive value of 24% and a negative predictive value of 95%, for the diagnosis of asthma.

Conclusions: Measuring FENO seems to be suitable as an adjunct to questionnaire in the evaluation of asthma in the general population.