Fraction of Exhaled Nitric Oxide (FeNO) Norms in Healthy Tunisian Adults

Abstract

Aims. To establish FeNOnorms for healthy Tunisian adults aged 18–60 years and to prospectively assess their reliability.Methods. This was a cross-sectional analytical study. A convenience sample of healthy Tunisian adults was recruited. Subjects responded to a medical questionnaire, and then FeNOlevels were measured by an online method (Medisoft, Sorinnes (Dinant), Belgium). Clinical, anthropometric, and plethysmographic data were collected. All analyses were performed on natural logarithm values of FeNO.Results. 257 adults (145 males) were retained. The proposed reference equation to predict FeNOvalue is lnFeNO(ppb) = 3.47−0.56× height (m). After the predicted FeNOvalue for a given adult was computed, the upper limit of normal could be obtained by adding 0.60 ppb. The mean ± SD (minimum-maximum) of FeNO(ppb) for the total sample was13.54±4.87(5.00–26.00). For Tunisian and Arab adults of any age and height, any FeNOvalue greater than 26.00 ppb may be considered abnormal. Finally, in an additional group of adults prospectively assessed, we found no adult with a FeNOhigher than 26.00 ppb.Conclusion. The present FeNOnorms enrich the global repository of FeNOnorms that the clinician can use to choose the most appropriate norms.