Background: Fractional exhaled nitric oxide is a method of assessing inflammation in the airway and its level may affected by some factors such as age, gender, and body mass index. This study was performed to assess the relationship between “Body Mass Index” (BMI) and FeNO.
Materials and Methods: This was a cross-sectional study on 879 adult subjects participating in the Shahedieh Cohort Study. BMI and FeNO were measured for each participant. Participants were divided into five BMI groups: underweight, normal, overweight, obese, and morbid obese FeNo level was compared between groups. The data were analyzed by SPSS (ver. 20) using Kolmogorov-Smirnov, Kruskal-Wallis, Mann-Whitney U tests, Spearman’s correlation, and multivariate logistic regression tests.
Results: The mean FeNO in all participants was 7.87±8.28 ppb. There was a significant positive correlation between age and FeNO. FeNO was declined by increasing BMI, so the highest FeNO was observed in underweight and the lowest FeNO was observed in morbid obese individuals. However, there was not a significant difference in FeNO level between different BMI categories (P =0.28). The mean FeNO level was significantly correlated to BMI only in participants younger than 48 years.
Conclusion: The results of this study showed that BMI is probably negatively correlated with FeNO level in middle-aged people younger than 48 years, but not in older people.