Body Mass Index is Inversely Correlated with Exhaled Nitric Oxide in Healthy Adults

Fractional exhaled nitric oxide (FENO) is widely used as a marker of inflammation in the airways. There is a paucity of data on the normal values of FENO in the general adult population and correlation with anthropometric factors. Therefore, we aimed to study the reference values of FENO among healthy, non-smoking male adults and determine its correlation with age, height, weight, body mass index and FEV1/FVC ratio. FENO was measured in healthy non-smoking Saudi male subjects by chemiluminescence using single-breath technique according to recent guidelines of American Thoracic Society. We studied 121 male subjects (mean age 31.00 +/- 12.24 years, height 171.79 +/- 8.3 cm, weight 80.17 +/- 18.38 kg, BMI 27.23 +/- 6.64, FEV1/FVC 85% (81 - 92 %). FENO measured at expiratory flow rates of 50mL/s ranged between 7.66 and 46.6 parts per billion (ppb) (mean 22.79 +/- 8.13), with >84% of subjects recording levels less than 30 ppb and >95% less than 40 ppb. FENO levels negatively correlated with body weight (r = 0.3888, p = 0.001) and BMI (r = 0.238, p = 0.009). No correlation was observed between FENO, FEV1/FVC ratio, age and height. The mean value of FENO for non-smoking, non-atopic male Saudi individuals is 22.79 +/- 8.13 ppb, similar to other populations & is negatively correlated with body weight and BMI.