Sleep Duration and Inflammation
Methods: A total of 614 individuals from the Cleveland Family Study completed questionnaires about sleep habits and underwent polysomnography. A morning fasting blood sample was assayed for 5 inflammatory cytokines.
Results: In this cohort, mean (SD) habitual sleep duration based on self-report was 7.6 (1.6) h and mean sleep duration by polysomnography (PSG) on the night prior to blood sampling was 6.2 (1.3) h. After adjusting for obesity and apnea severity, each additional hour of habitual sleep duration was associated with an 8% increase in C-reactive protein (CRP) levels (p = 0.004) and 7% increase in interleukin-6 (IL-6) levels (p = 0.0003). These associations were independent of self-reported sleepiness. In contrast, PSG sleep duration was inversely associated with tumor necrosis factor alpha (TNFα) levels. For each hour reduction in sleep, TNFα levels increased by 8% on average (p = 0.02). Sleep duration was not associated with IL-1 or IL-10.
Conclusions: Increases inhabitual sleep durations are associated with elevations in CRP and IL-6 while reduced PSG sleep duration is associated with elevated TNFα levels. Activation of pro-inflammatory pathways may represent a mechanism by which extreme sleep habits affect health.
Sanjay R. Patel, Xiaobei Zhu, Amy Storfer-Isser, Reena Mehra, Nancy S. Jenny, Russell Tracy, Susan Redline.
Sleep Duration and Biomarkers of Inflammation
Division of Pulmonary, Critical Care and Sleep Medicine, University Hospital Case Medical Center and Case Western Reserve University.