Sleep restoration is associated with reduced plasma C-reactive protein and depression symptoms in military personnel with sleep disturbance after deployment

Background: Deployed military personnel are vulnerable to chronic sleep disturbance, which is highly comorbid with post-traumatic stress disorder (PTSD) and depression, as well as declines in health-related quality of life (HRQOL). Inflammation is associated with HRQOL declines and sleep-related comorbidities; however, the impact of sleep changes on comorbid symptoms and inflammation in this population is unknown.

Methods: In this observational study, we examined the relationship between reported sleep changes and concentrations of inflammatory biomarkers, interleukin 6 (IL-6), and C-reactive protein (CRP) in peripheral blood. The sample was dichotomized into two groups: (1) decrease in Pittsburgh Sleep Quality Index (PSQI; restorative sleep) and (2) no change or increase in PSQI (no change). Mixed between-within subjects analysis of variance tests were used to determine group differences on changes of inflammation and comorbid symptoms.

Results: In our sample of 66 recently deployed military personnel with insomnia, 34 participants reported restorative sleep whereas 32 reported no sleep changes. The two groups did not differ in demographic or clinical characteristics, with the exception of PTSD diagnosis at baseline. The restorative sleep group had significant reductions in CRP concentrations and depression symptoms, as well as reduced fatigue and improvements in emotional well-being, social functioning, and physical functioning at follow-up.

Conclusions: Military personnel who report sleep restoration after deployment have reduced CRP concentrations, decreased severity of depression, and improved HRQOL. These findings suggest that treatment for sleep disturbances may be associated with improvements in mental and physical health, thereby supporting continued study in this line of research.