Abstract P052: History of High Cholesterol and Incidence of Dementia: The 90+ Study
Background: Hypercholesterolemia at midlife has been associated with increased dementia risk. However, some studies suggest that this relationship may change with age. It is not known if an association between cholesterol and dementia incidence persists in the oldest-old (people aged 90+) [[Unable to Display Character: –]] the most rapidly growing segment of the population. We examined whether a history of high cholesterol is associated with dementia incidence in The 90+ Study, a longitudinal population-based study of the oldest-old.
Methods: We analyzed data from 569 participants who were non-demented at baseline, had one or more follow-up visits, and provided self-reported history of high cholesterol. Participants were evaluated every six months, with dementia diagnosis (DSM-IV criteria) at follow-up determined in a hierarchal manner from: neurological exam, Mini-Mental Status Exam, informant questionnaires, and the Cognitive Abilities Screening Instrument (telephone short form). We used Cox regression to estimate the association between history of high cholesterol and incident dementia, using age as the time scale and adjusting for gender and education.
Results: Participants had a mean age of 93.3 years (range 90-103) at baseline and were primarily Caucasian (99%), women (69%), and with at least some college education (77%). 200 participants (35%) reported a history of high cholesterol. After a mean follow-up of 3.3 years (range 0.1-9.0), 224 individuals (39%) were diagnosed with dementia (68% from neurological exam). People who reported a history of high cholesterol at baseline were less likely to develop dementia compared to people without a history of high cholesterol (HR=0.76, 95% CI 0.57[[Unable to Display Character: –]]1.02, p=0.072).
Conclusions: Contrary to findings in younger ages, high cholesterol appears to be associated with lower dementia risk in the oldest-old. A potential mechanism could be that with advanced age a compensatory increase in cholesterol synthesis or uptake occurs in order to preserve function of the aging brain, as the cholesterol molecule has a variety of biological roles related to brain health. Further research is needed to analyze direct measurements of serum cholesterol, as well as to examine the effects of a variety of factors (such as use and duration of cholesterol-lowering medications, low cholesterol as a proxy for poor health and frailty, and duration of hypercholesterolemia) on the observed association. Our results imply that target cholesterol levels in the oldest-old may be different from those recommended in younger populations, at least in regards to cognitive health.
Author Disclosures: M.A. Evans: None. C.H. Kawas: None. M.M. Corrada: None.
- © 2014 by American Heart Association, Inc.