Serum cholesterol and cognitive performance in the Framingham Heart Study

Objective: The objective of this study was to examine the relationship between total cholesterol (TC) and cognitive performance within the context of the Framingham Heart Study, a large, community-based, prospective investigation of cardiovascular risk factors. Methods: Participants were 789 men and 1105 women from the Framingham Heart Study original cohort who were free of dementia and stroke and who received biennial TC determinations over a 16- to 18-year surveillance period. Cognitive tests were administered 4 to 6 years subsequent to the surveillance period and consisted of measures of learning, memory, attention/concentration, abstract reasoning, concept formation, and organizational abilities. Statistical models were adjusted for multiple demographic and biological covariates. Results: There was a significant positive linear association between TC and measures of verbal fluency, attention/concentration, abstract reasoning, and a composite score measuring multiple cognitive domains. Performance levels for three clinically defined groups were examined. Participants with "desirable" TC levels (<200 mg/dL) performed less well than participants with borderline-high TC levels (200-239 mg/dL) and participants with high TC levels (1240 mg/dL). Conclusions: Lower naturally occurring TC levels are associated with poorer performance on cognitive measures, which place high demands on abstract reasoning, attention/concentration, word fluency, and executive functioning.