CD34+CD133+ EPC proportion was associated with reduced risk of AD or all-cause dementia without adding covariates (Model 1), and remained significant after adjusting for covariates of age, sex, years of education (Model 2), and the addition of APOE ε4 and vascular diseases (Model 3), showing that a higher frequency of circulating CD34+CD133+ EPCs decreased AD risk (HR = 0.64, 95% CI = 0.44–0.94, P = 0.02) and all-cause dementia risk (HR = 0.63, 95% CI = 0.45–0.87, P = 0.006). Here, APOE is linked to Alzheimer disease.