Relationship Between Type 2 Diabetes Mellitus and Cognitive Change in a Multiethnic Elderly Cohort.

OBJECTIVES: To examine the association between diabetes mellitus and cognitive functioning at baseline and cognitive change over time in a large, ethnically diverse sample of older adults. DESIGN: Prospective cohort study. SETTING: Washington Heights-Inwood Columbia Aging Project, a community-based, prospective study of risk factors for dementia in northern Manhattan, New York City. PARTICIPANTS: Hispanic, non-Hispanic black, and non-Hispanic white men and women aged 65 and older without dementia at baseline (N = 1,493). MEASUREMENTS: Participants underwent baseline and follow-up cognitive and health assessments approximately every 18 months. Generalized estimating equations were used to examine the longitudinal association between diabetes mellitus and cognition. RESULTS: Diabetes mellitus was associated with poorer baseline cognitive performance in memory, language, processing speed and executive functioning, and visuospatial abilities. After adjusting for age, education, sex, race and ethnicity, and apolipoprotein-ε4, participants with diabetes mellitus performed significantly worse at baseline than those without in language and visuospatial abilities. There were no differences between those with and without diabetes mellitus in terms of rate of cognitive change over a mean follow-up time of 6 years. CONCLUSION: The rate of cognitive change in elderly persons with and without diabetes mellitus is similar, although cognitive performance is poorer in persons with diabetes mellitus. These findings suggest that cognitive changes may occur early during the diabetes mellitus process and highlight the need for studies to follow participants beginning at least in midlife, before the typical later-life onset of dementia.

Association of vascular risk factors with cognition in a multiethnic sample.

OBJECTIVES: To examine the relationship between cardiovascular risk factors (CVRFs) and cognitive performance in a multiethnic sample of older adults. METHOD: We used longitudinal data from the Washington Heights-Inwood Columbia Aging Project. A composite score including smoking, stroke, heart disease, diabetes, hypertension, and central obesity represented CVRFs. Multiple group parallel process multivariate random effects regression models were used to model cognitive functioning and examine the contribution of CVRFs to baseline performance and change in general cognitive processing, memory, and executive functioning. RESULTS: Presence of each CVRF was associated with a 0.1 SD lower score in general cognitive processing, memory, and executive functioning in black and Hispanic participants relative to whites. Baseline CVRFs were associated with poorer baseline cognitive performances among black women and Hispanic men. CVRF increase was related to baseline cognitive performance only among Hispanics. CVRFs were not related to cognitive decline. After adjustment for medications, CVRFs were not associated with cognition in Hispanic participants. DISCUSSION: CVRFs are associated with poorer cognitive functioning, but not cognitive decline, among minority older adults. These relationships vary by gender and medication use. Consideration of unique racial, ethnic, and cultural factors is needed when examining relationships between CVRFs and cognition.