Here's a study from the Journal of the American College of Cardiology
, concluding that
Higher cardiovascular risk burden may predict decline in episodic memory, working memory, and perceptual speed and is associated with neurodegeneration and vascular lesions in the brain.
Here's a quote from the results section, that seems
to suggest ApoE4 doesn't have the same impact from cardiovascular risk:
It is well known that APOE ε4 is a strong predictor of cognitive decline and dementia. Former studies have reported that the APOE ε4 allele was significantly associated with faster cognitive decline (4,13). In the current study, we found that the association between FGCRS and cognitive decline differed between APOE ε4 carriers and noncarriers. Specifically, the relationship between increased FGCRS [Framingham General Cardiovascular Risk Score]and faster cognitive decline was present mainly among APOE ε4 noncarriers. However, the interaction between FGCRS and APOE ε4 status on cognitive decline was not significant. There might be several explanations for this finding. First, the smaller sample size of APOE ε4 carriers may lead to a lack of power. Second, because APOE ε4 carriers are more likely to develop dementia, they might have been excluded at baseline.[emphasis added]
One chart in the article seems to suggest that ApoE4 might already have a baked-in effect: Over time the scores of study participants with ApoE 4 decline more than non-ApoE4 carriers on Global Cognition, Semantic Memory and Processing Speed when risk tertiles are combined. Middling good news: Changes in Episodic Memory, Working Memory and Visual Spatial Memory over time are no better and no worse between ApoE 4 and non-ApoE4 individuals.
If I'm reading this correctly, the title could have been "Individuals without ApoE 4 show association between cardiovascular risk and risk of dementia; people with ApoE4 must have something else going on".