Subjective Sleep Quality and Trajectories of Interleukin-6 in Older Adults

Background: We aimed to identify trajectories of inflammation in older adults at elevated risk for syndromal depression and anxiety and to determine whether baseline physical, cognitive, and psychosocial factors could distinguish 15-month longitudinal trajectories. Methods: Older adults (N = 195, mean age (±SD) = 74.4 years (9.0) participating in three depression and anxiety prevention protocols completed a comprehensive battery of psychosocial assessments and provided blood samples for analysis of interleukin-6 (IL-6) every 3 months over a maximum of 15 months. Group-based trajectory modeling identified trajectories. Adjusted logistic regression examined associations between baseline factors and trajectory groups. Results: Two 15-month trajectories were identified: stable lower IL-6 levels (84%; mean (±SD) = 3.2 (2.1) pg/mL); and consistently higher IL-6 levels (16%; mean = 9.5 (7.4) pg/mL). Poor sleep quality predicted consistently higher levels of IL-6 (OR = 1.9, 95% CI = 1.03–3.55). Conclusion: Poor sleep quality may represent a therapeutic target to reduce inflammation.