Diagnostic Assessment & Prognosis Mild cognitive impairment and dementia prevalence: The Atherosclerosis Risk in Communities Neurocognitive Study

Introduction: We examined prevalence of mild cognitive impairment (MCI) and dementiain the Atherosclerosis Riskin Communities(ARIC) Neurocognitive study. Methods: Beginning in June, 2011, we invited all surviving ARIC participants to undergo cognitive, neurologic, and brain imaging assessments to diagnose MCI or dementiaand assign an etiologyfor the cognitive disorder. Results: Of 10,713 surviving ARIC participants (age range, 69–88 years), we ascertained cognitive diagnoses in 6471 in person, 1966 by telephone interviews(participant or informant), and the remainder by medical record review. The prevalence of dementiawas 9.0% and MCI 21%. Alzheimer’s disease (AD) was the primary or secondary etiologyin 76% of dementiaand 75% of MCIparticipants. Cerebrovascular diseasewasthe primary or secondaryetiology in 46% of dementiaand 32% of MCI participants. Discussion: MCI and dementiawere common among survivors from the original ARIC cohort. Nearly 30% of the ARIC cohort received diagnoses of either dementiaor MCI, and for the majority of these individuals, the etiologicbasis was attributed to AD. 2016 The Authors. Published by Elsevier Inc. on behalf of the Alzheimer’s Association. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).