Is poor self-rated sleep quality associated with elevated systemic inflammation in healthy older adults?

Objective: Examine subjective sleep quality and inflammation among healthy older adults participating in the Australian Research Council Longevity Intervention (ARCLI).

Methods: Data was taken from a sub-set of 232 participants aged between 60-70 years (M = 65.88 ± SD 4.08 years) who participated in the baseline assessment phase of the Australian Research Council Longevity Intervention (ARCLI) study. Subjective sleep was assessed via the Leeds Sleep Evaluation Questionnaire (LSEQ). Inflammatory markers (TNF-α, IL-1β, IL-6, IL-10, IL-2, IFN-γ, IL-4, hs-CRP) were derived from whole blood. Correlation and multiple regression analyses were used to examine associations between each of the four sleep outcome variables and inflammatory outcomes, examined as a group and following gender stratification.

Results: Difficulties getting to sleep were independently associated with higher IL-2 [F = 4.62, adjusted R = 0.02, p = 0.03] and IL-1β [F = 8.52, adjusted R = 0.05, p = 0.004] (whole group). Difficulties getting to sleep were associated with greater IL-1β [males: F = 7.36, adjusted R = 0.097 p = 0.009; females: F = 4.25, R = 0.038, p = 0.04], and negatively associated with hs-CRP (women) [F = 4.71, R = 0.028, p = 0.032].

Discussion: Subjective sleep-onset difficulties are associated with systemic inflammation.