The potential contribution of APOE ε4 to cancer was also considered; though APOE ε4 alleles are significantly different between diagnostic groups as noted in the demographics table, individuals with APOE ε4 alleles were not more likely to have cancer history than those without at least one APOE ε4 allele, and this factor was also covaried for in all neuroimaging analyses to account for its impact on neurodegenerative processes in AD. Here, APOE is linked to Alzheimer disease.