Objective: We aimed to examine the association of APOE e genotype with MRI markers of cerebrovascular disease (CVD): white matter hyperintensities, brain infarcts, and cerebral microbleeds.Methods: We performed a systematic review and meta-analysis of 42 cross-sectional or longitudinal studies identified in PubMed from 1966 to June 2012 (n 5 29,965). This included unpublished data from 3 population-based studies: 3C-Dijon, Framingham Heart Study, and Sydney Memory and Ageing Study. When necessary, authors were contacted to provide effect estimates for the meta-analysis. Conclusions: APOE e4 and APOE e2 were associated with increasing burden in MRI markers for both hemorrhagic and ischemic CVD. While the association of APOE e4 with an increased burden of CVD could be partly contributing to the relationship between APOE e4 and AD, APOE e2 was associated with MRI markers of CVD in the opposite direction compared to AD. The e4 allele of the APOE gene is a major risk factor for dementia and Alzheimer disease (AD).
Results
1-6The association of APOE with cerebrovascular disease (CVD) is more controversial.7 APOE e4 is a risk factor for cerebral amyloid angiopathy (CAA), a major determinant of intracerebral hemorrhage (ICH) in older individuals.1 Recent data from the International Stroke Genetics Consortium suggest an association of APOE e4 with an increased risk of ICH, mostly lobar, 8 and an association of the APOE e2 allele with an increased risk and size of lobar ICH. 8,9 Whether the epsilon polymorphism is also associated with an increased risk of ischemic stroke and MRI markers of CVD is unclear.7 MRI markers of CVD-white matter hyperintensities (WMH), brain infarcts (BI), and cerebral microbleeds (CMB)-are powerful predictors of stroke and dementia.10-13 They are highly prevalent in older community-dwelling persons, [14][15][16] and can be assessed noninvasively and quantitatively in large population-based samples. Dissecting the relationship between APOE and MRI