ACE and Alzheimer disease: Further, the interaction between ApoE4 carrier status and central ACE inhibitor use (OR = 0.44, 95% CI = 0.33, 0.60, p < 0.0001) and the interaction between ApoE4 status and peripheral ACE inhibitor use (OR = 0.27, 95% CI = 0.16, 0.44, p < 0.0001) were associated with decreased risk of AD (Model III).