Gender differences in the prospective associations of self-reported sleep quality with biomarkers of systemic inflammation and coagulation: Findings from the Heart and Soul Study

Systemic inflammation is proposed as a putative mechanism underlying the link between poor sleep and cardiovascular disease. The aim of present study was to investigate the cross-sectional and prospective associations of self-reported sleep quality with biomarkers of inflammation and coagulation implicated in coronary heart disease (CHD) and to explore whether these associations differed between men and women. To this end, measures of sleep quality and markers of inflammation, including circulating levels of interleukin-6 (IL-6), high-sensitivity C-reactive protein (CRP), and fibrinogen were assessed at baseline in 980 participants with established CHD and 626 at 5-year follow-up. In the sample as a whole, subjective sleep quality was unrelated to inflammatory markers in cross-sectional and prospective analyses. However, in gender stratified analyses, adjusting for age, ethnicity, education, body mass index, and regular snoring, poorer subjective sleep quality at baseline was prospectively associated with 5-year increases in IL-6 (b = 0.14, SE = 0.05, p = 0.003), CRP (b = 0.21, SE = 0.09, p = 0.02), and fibrinogen (b = 18.02, SE = 7.62, p = 0.02) in women but not men. These associations remained independent of lifestyle/psychosocial factors, medical comorbidities, medication use, and cardiac function. Women who reported baseline sleep disturbances characterized by a tendency to wake up too early in the morning also showed significant 5-year increases in circulating IL-6 that withstood covariate adjustment. Further research is necessary to elucidate the pathways that underlie gender-specific associations between subjective sleep quality and markers of inflammation and coagulation as this may help clarify gender disparities in CHD. (C) 2013 Elsevier Ltd. All rights reserved.