Lack of Association Between Apolipoprotein E Polymorphism and Vascular Dementia in Koreans

To investigate an association of vascular dementia (VD) with the apolipoprotein E (APOE) polymorphism, the APOE polymorphism of 100 VD patients, 100 age- and gender-matched Alzheimer disease (AD) patients, and 200 age- and gender-matched nondemented control (NC) subjects was genotyped. The distribution of APOE polymorphism was compared. Neither the APOE ε4 allele nor the APOE ε2 allele was more prevalent in the VD patients compared with the NC subjects (P > .1 by the χ 2 test), which was the case when both men and women were analyzed separately (P > .1 by the χ2 test) and when young patients (75 years old or less) and old patients (more than 75 years old) were analyzed separately (P > .1 by the χ2 test). The estimated statistical power was over 0.80 when the odds ratios (OR) for VD conferred to the APOE ε4 are assumed to be higher than 2.2 and the type I error probability is set at 0.05, which is much higher than the power of the previous studies on the VD/APOE association. In conclusion, the results suggested that APOE ε4 allele does not confer the risk for VD, and even if it does, it does so very modestly.