Long sleep duration, independent of frailty and chronic Inflammation, was associated with higher mortality: A national population-based study

Aim: There is a complex interrelationship between long sleep duration, frailty, chronic inflammation and mortality among the community-dwelling middle-aged and elderly population, which remains unclear and deserves to be investigated. The current study intended to explore these associations by using a prospective population-based cohort study. Methods: A total of 937 community-dwelling middle-aged and elderly people were enrolled. Sleep patterns of the study participants were categorized as short (<6 h), average or long (>8 h). Sleep disturbance was defined by daytime dysfunction defined by the Pittsburg Sleep Quality Index. Frailty was defined as three or more phenotypes of Fried's Frailty. Results: During an average of 4.7 years follow up, 72 (7.7%) study participants died. The adjusted hazard ratio (HR) for death of long sleepers was 2.42 (95% confidence interval [CL11.38-4.27), HR of long sleepers plus frailty was 2.37 (95% Cl 1.35-4.19) and FIR of long sleepers plus log interleukin-6 was 2.11 (95% CI 1..19-3.76). Adjusted FIR of daytime dysfunction was 1.79 (95% CI 1.09-2.94). The association between daytime dysfunction and mortality became statistical insignificant after further adjustment for frailty. Conclusions: Long sleep duration, independent of frailty and interleukin-6, was associated with 5-year mortality in older adults. The relationship between daytime dysfunction and death diminished after adjusting for frailty.