APOE and Alzheimer disease: Several studies4,5,6,32 have described APOE ε4 risk alleles and sex as risk factors for neuropathologic outcomes in people with TBI and showed that the associations of TBI with dementia or AD-related pathologic outcomes are greater in people with APOE ε4 risk alleles than in non–APOE ε4 carriers and in men than in women,23 whereas some studies12,33 have found no differences.