Despite no significant association in APOE ε4 carriers that did not harbor the APOC1 insertion allele (χ2 = 1.11, OR = 0.86, 95% CI = 0.65–1.14, P = 0.29), and APOC1 insertion allele carriers that did not harbor APOE ε4 (χ2 = 1.04, OR = 1.13, 95% CI = 0.90–1.41, P = 0.31), APOE ε4 carriers harboring the APOC1 insertion allele, were more prevalent in AD patients than controls (χ2 = 119.46, OR = 2.79, 95% CI = 2.31–3.36, P<0.01). Here, APOE is linked to Alzheimer disease.