Using the longitudinal data from the National Alzheimer’s Coordinating Center (NACC) with ApoE genotyping and documentation of ACE inhibitors use, we found that in the absence of ApoE4, subjects who had been taking central ACE inhibitor use (χ2 test: 21% versus 27%, p = 0.0002) or peripheral ACE inhibitor use (χ2 test: 13% versus 27%, p < 0.0001) had lower incidence of AD compared with those who had not been taking an ACE inhibitor. This evidence concerns the gene APOE and Alzheimer disease.