30. Secondary Analysis of Sleep Functioning and Interleukin-6 Levels Between Controls and Athletes Following Sport-related Concussion

Abstract

Interleukin 6 (IL 6) is an inflammatory cytokine that may be acutely elevated within the acute phase following sport related concussion. IL-6 has been an area of interest as a peripheral blood-based biomarker; however, few studies have examined IL-6 in relation to sleep functioning. We hypothesized there would be differences in sleep functioning and IL-6 levels reflected in immunoassay between concussed and control athletes. Data were obtained from a prospective, observational cohort study conducted on athletes at an academic institution to conduct a secondary post-hoc analysis. Participants comprised of 41 athletes diagnosed with SRC and 55 health controls for a total of 96 participants. ANCOVA was utilized to identify group differences in sleep functioning and IL-6 levels, while linear regression was used to assess the relationship between IL-6 and sleep functioning. Demographics, recovery data (i.e., time to clearance), and concussion-related symptoms were gathered via the Sport Concussion Assessment Tool - 5 (SCAT-5) No differences in IL-6 were observed between concussed and control athletes. IL-6 levels did not predict sleep symptoms. However, there were statistically significant differences in total symptoms, overall symptom severity, and emotional, somatic, cognitive, and sleep symptoms (all p<0.001). Group differences in symptom burden within the sleep domain of the SCAT-5 were observed, as well as all other domains captured within the SCAT-5. An absence of differences in IL-6 levels may be attributable to small sample size or immunoassay protocol. Future research should examine this phenomenon in a larger sample and include additional biomarkers to explore other neurobiological implications for sleep architecture.