Abstract WMP115: The Metabolic Syndrome Components and Cognitive Decline: The Atherosclerosis Risk in Communities (ARIC) Study

Abstract

Background: Midlife obesity is associated with dementia in later life, but how the metabolic syndrome (MetS) relates to cognitive change is less understood. We hypothesized that MetS would be more predictive of 6-year cognitive decline than its individual components in a large biethnic cohort (the ARIC study) and that combinations of risk factors would further increase likelihood of change. Methods: The MetS was defined in 1987-89 on 10,687 participants with two cognitive assessments at two time points. In subjects aged 44 to 66, obesity measures included body mass index (BMI) and waist-to-hip ratio (WTHR). The main outcome measure was change in 1990-92 to 96-99 of three cognitive tests: Delayed Word Recall (DWR), Digit Symbol Substitution Test (DSST), and Word Fluency Test (WFT). Linear and logistic regressions were all adjusted for age, combined race-center, sex, education, smoking, drinking, coronary artery disease and prior stroke. Change was measured as the difference divided by the number of years between visits. Results: At baseline, the prevalence of MetS was 22% (mean age 54 years, 27% black, 55% female, and 28% BMI>30 kg/m2). Subjects with MetS performed in the lowest test quintile (adjusted ORs: DWR 1.3 95% CI 1.1-1.4) in 1996-99, and much of this effect size was explained by an elevated WTHR (DWR OR 1.3 CI 1.1-1.5) and diabetes (DWR OR 1.4 CI 1.2-1.7). MetS was not associated with annual cognitive change, and diabetes was the only significant component associated with change (adjusted beta: DWR 0.03 p=.01, DSST 0.2 p<.001, WFT 0.09 p=.01). Conclusion: MetS at ages 44 to 66 was associated with worse cognitive function at follow-up, but not with annual cognitive decline over several years. Elevated WTHR and diabetes explained most of the association of MetS with cognitive function measures, and diabetes with cognitive decline. Until we have a definition of the MetS more based on pathophysiology, the components of the MetS should be the focus of analysis in future studies.