To the Editor A recent propensity-matched cohort study of more than 350 000 veterans with and without traumatic brain injury (TBI) by Barnes et al1 found that mild TBI was associated with more than a 2-fold increase in the risk of dementia, yielding implications for long-term neurodegenerative consequences following TBI. This longitudinal study allowed for the power to detect associations and to adjust for a range of potential confounders, including other medical and psychiatric comorbidities. While we applaud the authors and feel the findings are important, we note a discrepancy in their report of comorbidities, specifically “sleep disorders” (ie, sleep apnea, insomnia, hypersomnia, parasomnia, and circadian rhythm disorders).