Contribution of Inflammation, Oxidative Stress, and Antioxidants to the Relationship between Sleep Duration and Cardiometabolic Health.

OBJECTIVES: To explore the interrelationship and mediating effect of factors that are beneficial (i.e., antioxidants) and harmful (i.e., inflammation and oxidative stress) to the relationship between sleep and cardiometabolic health.
DESIGN: Cross-sectional data from the 2005-2006 National Health and Nutrition Examination Survey.
SETTING: Nationally representative population sample from the US. PARTICIPANTS: Age ≥ 20 y with sleep data; final analytical sample of n = 2,079.
INTERVENTIONS: N/A. MEASUREMENTS AND
RESULTS: Metabolic syndrome was classified according to the Joint Interim Statement, and sleep duration was categorized as very short, short, adequate, and long sleepers (≤ 4, 5-6, 7-8, and ≥ 9 h per night, respectively). The indirect mediation effect was quantified as large (≥ 0.25), moderate (≥ 0.09), modest (≥ 0.01), and weak (< 0.01). In general, inflammation was above the current clinical reference range across all sleep duration categories, whereas oxidative stress was elevated among short and very short sleepers. Select sleep duration- cardiometabolic health relationships were mediated by C-reactive protein (CRP), γ-glutamyl transferase (GGT), carotenoids, uric acid, and vitamins C and D, and were moderated by sex. Specifically, moderate-to-large indirect mediation by GGT, carotenoids, uric acid, and vitamin D were found for sleep duration-waist circumference and -systolic blood pressure relationships, whereas vitamin C was a moderate mediator of the sleep duration-diastolic blood pressure relationship.
CONCLUSIONS: Several factors related to inflammation, oxidative stress, and antioxidant status were found to lie on the casual pathway of the sleep duration-cardiometabolic health relationship. Further longitudinal studies are needed to confirm our results.