Background: Exhaled nitric oxide (FeNO) is increased in type-2 airway inflammation; it is also affected by several individual factors, although they are not commonly considered when evaluating FeNO in the clinic. We aimed to further evaluate the effect of anthropometric measures on FeNO in a large healthy population-based sample.
Methods: A total of 8,581 non-smoking subjects (6-79 years old), without self-reported respiratory disease, and without respiratory symptoms and hay fever the last year that participated in the US NHANES 2007-2012 were included and divided into four groups according to age (< and >= 18 years) and sex: 2,974 children (50% males) and 5,607 adults (51% males). The association between FeNO and height (cm) and weight (kg) were evaluated with ANCOVA models in the four groups, with the covariates being age (years), and serum cotinine (ng/mL) as marker of passive smoking.
Results: Age associated positively with FeNO in male and female adults (p < 0.001 all) but not children (males, p = 0.068 and females, p=0.145), whereas height related positively to FeNO in all groups (p<0.021 all) except adult females (p=0.291). Instead, weight associated with increasing FeNO in this group (p=0.049). Cotinine related negatively to FeNO in all groups (p<0.002 all), except female children (p=0.197).
Conclusion: Weight seems to associate more closely than height with increasing FeNO in adult females, which warrants further studies on the potential relationship between type-2 inflammation and increased adipose tissue in females. The negative association with serum cotinine revealed an influence of passive cigarette smoke exposure on FeNO.