Abstract
Introduction: Exhaled nitric oxide is a useful, non-invasive measure of airway inflammation in asthma. C-reactive protein and fibrinogen are markers of systemic inflammation, which are raised in obesity. It is unknown whether airway inflammation, as measured by exhaled nitric oxide, is associated with systemic inflammation. Such an association could help to explain the link between asthma and obesity.
Methods: The Dunedin Multidisciplinary Health and Development Study is a population-based cohort of 1037 individuals born in 1972/73. At age 32 years, Study members were assessed for asthma, atopy, smoking and body mass index (BMI). Exhaled nitric oxide levels (eNO), high-sensitivity CRP and fibrinogen were measured.
Results: There was no significant association between eNO and CRP. This remained the case after adjustment for smoking, corticosteroid therapy, atopy, and BMI. There was an inverse association between eNO and fibrinogen in a sex-adjusted regression model (p = 0.049), but this was not significant after adjustment for smoking or further adjustment for corticosteroid therapy, atopy, and BMI.
Conclusion: In this population-based sample of young adults, there was no association between airway inflammation as measured by exhaled nitric oxide, and systemic inflammation as measured by either CRP or fibrinogen. Our findings do not help to explain the link between asthma and obesity.