The report, titled “Traumatic brain injury may not increase the risk of Alzheimer disease” cites three large, well-powered, and carefully conducted studies that cast substantial doubt on the association between TBI exposure and AD outcomes, both overall and among men and carriers of APOE4 alleles (Gardner et al., 2015; Crane et al., 2016; Weiner et al., 2017b). This evidence concerns the gene APOE and Alzheimer disease.