Abstract
Abstract only Introduction: Apolipoprotein E4 (ApoE4) allele is linked to increased LDL-Cholesterol, one of the main risk factors for intracranial large artery stenosis (ICAS). Evidence shows that in diabetic men, intima-media thickness is significantly higher in those with ApoE4 than those with ApoE3. While the link between ApoE4 and extracranial atherosclerosis and vascular risk factors is established, the association of these vascular factors with ICAS is unknown. This study investigates the relationship between ApoE4 carrier status and ICAS and whether vascular risk factors influence this relationship. Methods: We rated intracranial large arteries on MR-angiography for their degree of stenosis as 0=no stenosis, 1=<50% stenosis, 2=50-69%, 3=70% or flow gap. We added the score of each of the 11 intracranial arteries to reflect a composite measure of the severity of ICAS. We then related ApoE4 carrier status to the ICAS score using generalized linear models with a Poisson link, adjusting for demographics, vascular risk factors, and cohort. We ran pre-specified interaction models with demographics and vascular risk factors. Results: 4099 individuals from six cohorts were included; 58% were women, the prevalence of hypertension was 76%, diabetes 31%, dyslipidemia 64%, and current smoking 13% (Table). There was no association between ApoE4 carrier and ICAS score (B= 0.08+0.06, p=0.19), but we found statistical interactions between ApoE4 carrier and male sex (p=<0.001), current smoking (p=0.05), and hypertension (p=0.003). ApoE4 carrier status was associated with higher ICAS score among hypertensive men (B=0.52±0.11, P=<0.001) and hypertensive people who smoke (B=0.58±0.20, p=0.01. Conclusion: ApoE4 carrier status was not associated with ICAS overall, but there were associations in subgroups defined by sex, hypertension, and smoking. Whether these interactions influence the risk of stroke and dementia should be further investigated.