B – 43 Effects of TBI and Sleep Apnea on Clinical Outcomes in Veterans: A VA Million Veteran Program Study

Objective Traumatic brain injury (TBI) and obstructive sleep apnea (OSA) are significant health concerns and highly prevalent in Veteran populations. Both conditions have been independently linked to a range of adverse clinical outcomes, specifically impaired cognitive and emotional functioning. We aimed to explore the interplay between TBI and OSA in relation to cognitive and mental health difficulties within a sample of Iraq/Afghanistan-era Veterans. Method This study included 16,452 Veterans (76% male, age: M=43.3 years [SD=11.0]) who enrolled in the VA Million Veteran Program and completed the TBI Clinical Reminder Screen and a comprehensive health history survey to assess probable history of TBI and OSA, respectively. The primary outcomes included: the Medical Outcomes Study Cognitive Functioning Scale-Revised (MOS-Cog-R) for cognitive symptoms and the Patient Health Questionnaire-4 (PHQ-4) for anxiety/depression symptoms. Results The sample included 5,656 with a probable TBI history (TBI+) and 10,796 without (TBI-), and 4,911 with probable OSA (OSA+) and 11,541 without (OSA-). Two-way analyses of covariance revealed significant main effects and interactions of TBI and OSA with subjective cognition; while OSA+ was associated with worse cognitive symptoms in both TBI groups, this pattern was more pronounced in the TBI+ group (p<.001, ηp2< 0.001). We also found similar effects with self-reported mental health symptoms; the OSA+ group was associated with increased anxiety/depression symptoms, particularly in the TBI+ group (p=.009, ηp2< 0.001). Conclusion Our findings underscore a potential interaction between TBI and OSA leading to worse cognitive and mental health outcomes, suggesting that monitoring and addressing OSA may be crucial for Veterans with a TBI history.