The effect of sleep duration on exhaled nitric oxide levels in U.S. adults

Purpose: Poor sleep quality and duration are associated with systemic endothelial dysfunction. However, an association between poor sleep and pulmonary endothelial dysfunction has not been elucidated. We sought to determine if there is a relationship between sleep duration and fractional exhaled nitric oxide (FeNO) concentrations as a surrogate for pulmonary endothelial function. Methods: We used three National Health and Nutrition Examination Survey (NHANES) cycles (2007–2012). Linear regression models were built with and without adjustment for age, sex, race, BMI, asthma/bronchitis, CRP, smoking, folate, renal function, respiratory infections, and steroid use. To examine a non-linear relationship, we introduced a spline, with single knot at mean sleep duration (7 h). Results: Of 13,173 participants (50.8% male, 44.2% Caucasian), 78% slept 6–8 hours (h). FeNO was significantly higher in the group sleeping 6–8 h (17.3 ± 14.9 ppb) than in the other two groups (16.0 ± 13.0 ppb, 15.9 ± 12.7 ppb for <6 and >8 h respectively; P < 0.001). In unadjusted linear regression, FeNO increased by 1.1 ppb for each hour increase in sleep up to 7 h (P < 0.001). Increased sleep duration beyond 7 h saw a 0.96 ppb decrease in FeNO (P < 0.001). After adjustment for confounders, FeNO increased by 1.09 ppb for each hour of sleep up to 7 h (P = 0.001) and decreased by 0.71 ppb for each hour after (P = 0.02). Conclusion: Sleeping less or more than 7 h is associated with pulmonary endothelial dysfunction as measured by FeNO. Further study is needed to evaluate mechanism(s) of this association and validity of FeNO as a marker of endothelial function.