Incidence of Mild Cognitive Impairment in the CHS Cognition Study (S24.001)

Abstract

Objective: To examine the incidence of mild cognitive impairment (MCI) in the Cardiovascular Health Study-Cognition Study. Background Older subjects with MCI have an increased risk of developing dementia. Design/Methods: We examined the incidence of MCI and patterns of progression from incident MCI to dementia in 285 normal subjects (mean age: 78.9) participating in the CHS-CS from 1998-99 to 2010-2011. Results: 200 (70%) of the participants progressed to MCI; the age-adjusted incidence of MCI was 112.09 (95% CI: 88.1 – 142.95) per/1000 persons-years. 110 (55%) of the incident MCI subjects progressed to dementia. The mean time to MCI was 5.9 + 2.7 years and from the MCI to dementia 2.8 + 1.8 years. 40 (20%) of the incident MCI cases had an “unstable” course: 19 (9.5%) converted to MCI and later returned to normal, 10 (5%) converted to MCI to normal and later went back to MCI, 7 (3.5%) converted to MCI to normal to MCI and later to dementia, and 4 (2%) converted to MCI to normal and later to dementia. Conclusions: The majority of the subjects older than age 80 developed an MCI syndrome and half progressed to dementia. Progression from normal to MCI or from normal to MCI to dementia is not always linear; 20% of the subjects had a fluctuating course. Subjects who developed MCI and later returned to normal can progress to dementia during follow-up. Importantly, once the MCI syndrome is present, the symptoms of dementia appear within 2-3 years. This suggests that the window to detect symptomatic pre-dementia cases is narrow in this age group, which has important implications for the development of prevention therapies. Supported by: The research reported in this article was supported by contracts N01-HC-85079 through N01-HC-85086, N01-HC-35129, and N01-HC-15103 from the National Heart, Lung, and Blood Institute, and grants AG15928 and AG20098 from the National Institute on Aging. Disclosure: Dr. Lopez has received personal compensation for activities with Lundbeck and Johnson & Johnson as a consultant. Dr. Becker has nothing to disclose. Dr. Chang has nothing to disclose. Dr. Sweet has nothing to disclose. Dr. DeKosky has received personal compensation in an editorial capacity for Up-to-Date, Inc. Dr. Gach has nothing to disclose. Dr. Carmichael has nothing to disclose. Dr. McDade has nothing to disclose. Dr. Kuller has nothing to disclose.