Effects of TBI history and sleep on subjective cognition in Veterans: A VA Million Veteran Program study

Traumatic brain injury (TBI) is a major public health issue often linked to cognitive dysfunction, with poor sleep further compounding these difficulties. While poor sleep has been shown to exacerbate post-TBI cognitive deficits, its role among Veterans remains understudied. This study examined the association between TBI history and poor sleep, as well as the interaction between TBI and sleep on subjective cognitive symptoms in a sample of 6959 Iraq/Afghanistan-era Veterans (77 % male) enrolled in the VA Million Veteran Program (MVP). Veterans completed the TBI Screening and Evaluation Program as well as a comprehensive health history survey from MVP including two items assessing sleep: sleep duration and sleep disturbance. Subjective cognitive symptoms were assessed using the Medical Outcomes Study Cognitive Functioning Scale - Revised (MOS-Cog-R) from the MVP survey. Chi-square analyses and two-way analyses of covariance revealed that Veterans screening positive for TBI reported poorer sleep (i.e., less duration and more sleep disturbance) compared to Veterans screening negative for TBI. Linear regressions examining associations between TBI, sleep, and subjective cognition showed significant main effects of TBI and sleep, as well as a significant interaction between TBI and sleep on subjective cognition. Specifically, reduced sleep duration and increased sleep disturbance were associated with worse cognitive symptoms, particularly for Veterans screening positive for TBI. Results highlight the complex interrelationships between TBI, sleep, and subjective cognition in a large Veteran population, and underscore the importance of assessing and addressing sleep problems in Veterans with a probable history of TBI, with implications for treatment and recovery.