Sleep duration, sleep quality, and biomarkers of inflammation in a Taiwanese population.

PURPOSE: Short and long sleep duration and sleep quality are associated with health including all-cause mortality, cardiovascular disease, diabetes, and obesity. Inflammation may play a role in mediating these associations. METHODS: We examined associations between inflammation and self-reported sleep characteristics in 1020 respondents of the 2000 and 2006 Social Environment and Biomarkers of Aging Study, a nationally representative survey of Taiwanese adults ages 53 and over. Regression models were used to estimate cross-sectional relationships between inflammation (interleukin-6, C-reactive protein, fibrinogen, e-selectin, soluble intercellular adhesion molecule-1, albumin, and white blood cell count) and a modified Pittsburgh Sleep Quality Index, index subcomponents, and self-reported sleep duration. Change in inflammatory markers between 2000 and 2006 was also used to predict long or short sleep duration in 2006. RESULTS: Inflammation was not related to the overall index of sleep quality. However, longer sleep (>8 hr) was associated with higher levels of inflammation. These associations remained after adjustment for waist circumference, self-reported health decline, diabetes, arthritis/rheumatism, heart disease, and depressive symptoms. Increases in inflammation between 2000 and 2006 were associated with long but not short sleep duration in 2006 for several markers. CONCLUSIONS: Long sleep duration may be a marker of underlying inflammatory illness in older populations. Future studies should explore whether inflammation explains observed relationships between long sleep and mortality.