Date of Award

Summer 8-18-2017

Level of Access Assigned by Author

Open-Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Psychology

Advisor

Merrill F. Elias

Second Committee Member

Michael A. Robbins

Third Committee Member

Adam Davey

Additional Committee Members

Alan M. Rosenwasser

Lenard W. Kaye

Abstract

The association of cardiovascular risk factors including hypertension, diabetes, cholesterol, kidney function, and arterial stiffness with cognitive impairment in older adults is a well-studied phenomenon. However, there is considerably less evidence relating cardiovascular health specifically to a diagnosis of Mild Cognitive Impairment (MCI). As a precursor state of dementia, MCI is characterized by a decline in cognitive function from previous level, but not to the degree that activities of daily living are impaired. Not everyone who is diagnosed with MCI will eventually transition to dementia, but the transition rates are much higher compared to the general population (5-15% per year compared to 1-2%). The primary aim of the current investigation is to examine the relationship between individual cardiovascular risk factors and 5-year incident MCI risk and to investigate whether these relationships are moderated by apolipoprotein E genotype (APOE). An additional primary aim was to investigate whether an aggregation count of cardiovascular risk factors (MSLS-CVRFS) and two common cardiovascular risk factor profiles (FRS and ASCVD risk score) were related to 5-year incident MCI risk. Following exclusions for dementia, the study sample included 625 (Average baseline age: 61.98, 61% female) participants from the 6th and 7th waves of the Maine-Syracuse Longitudinal Study (MSLS). MCI diagnosis was made by a team of three investigators applying established MCI diagnostic criteria, with 96 participants diagnosed with possible MCI. Multiple logistic regression analysis was used to examine the association between individual baseline cardiovascular risk factors (SBP, TC, HDL, LDL, TRIG, GFR, THCY, Diabetes, PWV) and MCI with adjustment for basic demographic covariates including age, sex, years of education, and ethnicity. The same method was used for determining APOE interaction effects and relating cardiovascular risk factor scores (CVRFS, FRS, ASCVD) with MCI risk. Among individual risk factors, higher GFR and HDL were associated with lower MCI risk, while diabetes was associated with higher MCI risk. No APOE interaction effects were observed. All three of the cardiovascular risk factor scores tested were associated with higher MCI risk. These findings have clinical implications with regard to predicting MCI risk with a combination of cardiovascular risk factors. While these factors have previously been related to continuously distributed cognitive performance measures, it is critical that their relationship to a clinically defined binary outcome like MCI be investigated because treatment decisions are based on diagnosis.

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