Date of Award

Summer 2020

Document Type

Open Access Dissertation

Department

Epidemiology and Biostatistics

First Advisor

Anwar T. Merchant

Abstract

Intracranial Atherosclerotic Stenosis (ICAS) is associated with 8 to 10% of all strokes in the U.S. Although there is some evidence that in the Asian population inflammation plays a role in asymptomatic ICAS, it has not been shown in the U.S. population. Prior studies have shown associations between diet and regulation of inflammation. Mediterranean dietary pattern has been associated with lower levels of inflammation and cardiovascular disease (CVD). In light of the important role of inflammation in intermediate stroke risk factors including atherosclerotic disease, and potential role of diet in modulating inflammation, understanding individuals’ diets according to their inflammatory properties could yield important information about the links between diet, inflammation, and ischemic stroke. Our objectives for this study were two-fold. First, we assessed if high sensitivity C-reactive protein (hs-CRP), a marker of inflammation is associated with asymptomatic ICAS. Second, we assessed if Mediterranean dietary adherence is associated with ICAS, and if this association is modified with individual’s inflammatory state.

Data came from the Atherosclerosis Risk in Communities Cohort, a community-based, prospective cohort total of 15,792 participants, aged 45 to 64 years recruited in1987 to 1989. We included 1,445 participants from this cohort who attended Visit 5 (2011-2013) and underwent high resolution MR angiography (MRA). MRA images were analyzed in a centralized lab to assess ICAS (outcome) and ICAS was graded as: no vi stenosis,3 mg/l) and ICAS. Further to assess Mediterranean dietary adherence we constructed an adapted Mediterranean Dietary Score (aMDS), that included the following 11 food components: non-refined cereals (whole grains), fruits, vegetables (excluding potatoes), nuts, legumes, fish, monounsaturated-to-saturated fat ratio (as an alternative for olive oil), red and processed meats, dairy products, poultry and alcohol. The aMDS ranged from 0 to 55, with higher values indicating greater adherence to the Mediterranean diet. Multinomial logistic regression models were used to assess the association between the Tertiles of the aMDS and ICAS.

Our findings strongly suggest participants with elevated hs-CRP over a period of 6 years had a strong association with both moderate and severe ICAS. Participants with increased hs-CRP over this 6 years period had increased odds for severe ICAS, however those with deceased hs-CRP did not. Further, when assessing association between Mediterranean diet and ICAS our results were somewhat suggestive of decreased burden of ICAS with Mediterranean diet adherence however, these findings were not statistically significant. Our findings also suggest inflammation (as measured by hs-CRP) may be an effect modifier for the association between Mediterranean diet and ICAS, with those with higher hs-CRP may benefit from Mediterranean diet adherence.

Available for download on Monday, August 15, 2022

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