Abstract 34: Association of Carotid Intima-Media Thickness and Other Carotid Ultrasound Features With Incident Dementia in The Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS)

Abstract

Background: Increased carotid intima-media thickness (cIMT), a measure of carotid artery thickness, and carotid plaque are predictors of cardiovascular disease and atherosclerosis. Likewise, increased interadventitial diameter (IAD), which references arterial remodeling, and lower carotid distensibility coefficient (DC), which indicates carotid stiffness, are also predictors. These indices likely relate to cerebrovascular disease, and thus may constitute a form of vascular contributions to dementia and Alzheimer’s disease and related dementias. Therefore, we assessed the relationship of carotid measures and distensibility with incident dementia in the Atherosclerosis Risk in Communities (ARIC) study. Methods: 12,459 ARIC participants who had carotid ultrasound measurements in 1990-92 were followed through 2017 for incident dementia. Dementia cases were identified using in-person and phone cognitive status and informant assessments, hospitalization discharge codes, and death certificate codes. Cox proportional hazards models were used to estimate the hazards ratios for incident dementia per 1-SD and per quintile increment in arterial index (cIMT, IAD, and DC) and for presence of carotid plaque. Results: Participants were aged 57±6 at baseline, 57% were female, and 23% were black. Over a median follow-up of 24 years, 2,224 dementia events were ascertained. After multivariable adjustments, the highest quintile of both cIMT and IAD in midlife were associated with increased risk of incident dementia (Table; HRs [95% CIs]: 1.33 [1.15, 1.54]; 1.24 [1.06, 1.46]), while presence of carotid plaque was not (HR [95% CI]: 1.06 [0.97, 1.15]). Additionally, higher distensibility was associated with lower risk of dementia (HR [95% CI] highest vs. lowest quintile: 0.73 [0.61, 0.88]). Conclusion: Increased cIMT, IAD, and lower carotid distensibility are associated with an increased risk of incident dementia. These findings suggest that both atherosclerosis and carotid stiffness may be implicated in dementia risk.