Relationships between cerebrovascular events, APOE polymorphism and Alzheimer's disease in a community sample

To investigate whether the APOE*4 allele modified the relationship between cerebrovascular events and Alzheimer's disease (AD), we collected evidence of previous stroke or transient ischemic attack (TIA) and determined APOE genotype among 102 subjects with AD and 375 nondemented subjects in a community-based study of dementia. Subjects with a history of stroke or TIA were twice as likely to have AD as subjects without such a history. However, APOE*4 carriers with a history of stroke/TIA were 5 times more likely than APOE*4 carriers without such a history to have AD (odds ratio = 5.3, 95% confidence interval = 1.4-20.9). History of stroke/TIA had little effect on the likelihood of having AD in subjects without an APOE*4 allele.