Are lower naturally occurring total cholesterol levels associated with poorer cognitive performance in adults free of dementia and stroke?
Lower naturally occurring total cholesterol levels are associated with poorer performance on cognitive measures involving abstract reasoning, attention, and executive functioning.
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 (there exists 240 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.
Elias et al. (2005) studied this question.