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Introduction: Research on factors associated with late-life cognitive performance in diverse racial/ethnic groups is increasingly important due to the growing size and racial diversity of the elder population. Methods: Using data on American Indians (AIs) from the Strong Heart Study, we measured associations between mid-life physical activity (PA), assessed by a questionnaire or pedometer, and performance on tests of general cognitive function, phonemic fluency, verbal learning and memory, and processing speed. Cognitive tests were administered 7–21 years after PA measurements. To estimate associations, we used regression models with and without inverse-probability weights to account for potential attrition bias in the cohort. Results: Questionnaire and pedometer measures of PA were positively associated with cognitive function. Participants in the top quartile of questionnaire-based PA had Modified Mini-Mental State examination scores 3.2 (95% CI: 1.5–4.9) points higher than participants in the lowest quartile. Phonemic fluency scores also trended higher for participants in the top compared to the bottom categories for both PA measures: top questionnaire quartile = 2.7 (95% CI: 0.6–4.8) points higher and top pedometry tertile = 6.7 (95% CI: 2.7–10.7) points higher. We observed no associations between PA and tests assessing verbal learning and memory, or processing speed. Weighted model results were similar, but less precise. Conclusions: In this cohort of AIs with relatively low levels of PA, positive associations between mid-life PA and late-life cognitive performance were dose-dependent and of modest clinical significance. [ABSTRACT FROM AUTHOR]

BACKGROUND American Indians have excess risk of depression, which can contribute to cerebrovascular and cognitive disability, with effects on memory, processing speed, executive function, and visuospatial ability. However, studies examining depression and cognition in American Indians are limited; this study aims to report associations of depression with general cognition, verbal fluency and memory, and processing speed. DESIGN Cohort study. SETTING The Cerebrovascular Disease and its Consequences in American Indians study was an ancillary examination of Strong Heart Study participants from 3 U.S. regions. PARTICIPANTS All eligible were included in this analysis (N=818). MEASUREMENTS Participants completed evaluations for depressive symptomology, cognition, and physical function—including Center for Epidemiologic Studies Depression (CESD), Modified Mini‐Mental State Examination (3MSE), Wechsler Adult Intelligence Scale‐Fourth Edition coding (WAIS), Controlled Oral Word Association (COWA), California Verbal and Learning Test, Halstead finger tapping, grip strength, and Short Physical Performance Battery (SPPB) tests. Linear mixed models were adjusted for site, age, sex, education, income, marital status, alcohol, smoking, diabetes, hypertension, obesity, cholesterol, stroke, infarct, and hemorrhage. RESULTS: Symptoms of depression were common, with 20% (N=138) endorsing CES‐D scores of 16+. More depressive symptoms were associated with older age, female sex, lower education, lower income, non‐married status, not using alcohol, not smoking, hypertension, diabetes, and stroke. In adjusted analyses, processing speed (WAIS: β −0.13, 95%CI −0.25, −0.03), general cognition (3MSE: β −0.10, 95%CI −0.17, −0.03), verbal fluency (COWA: β −0.10, 95%CI −0.19, −0.01), and motor function (SPPB: β −0.05, 95%CI −0.07, −0.03) were significantly associated with more symptoms of depression. CONCLUSION: These findings maybe informative for health disparities populations, especially those with depressive risk. Clinicians may require particular training in cultural humility. Future studies should validate use of the CES‐D scale in this population; longitudinal studies may focus on causal mechanisms and potential secondary prevention, such as social support. J Am Geriatr Soc 68:1739‐1747, 2020. [ABSTRACT FROM AUTHOR]

Objective: American Indians experience substantial health disparities relative to the US population, including vascular brain aging. Poorer cognitive test performance has been associated with cranial magnetic resonance imaging findings in aging community populations, but no study has investigated these associations in elderly American Indians. Methods: We examined 786 American Indians aged 64 years and older from the Cerebrovascular Disease and its Consequences in American Indians study (2010–2013). Cranial magnetic resonance images were scored for cortical and subcortical infarcts, hemorrhages, severity of white matter disease, sulcal widening, ventricle enlargement, and volumetric estimates for white matter hyperintensities (WMHs), hippocampus, and brain. Participants completed demographic, medical history, and neuropsychological assessments including testing for general cognitive functioning, verbal learning and memory, processing speed, phonemic fluency, and executive function. Results: Processing speed was independently associated with the presence of any infarcts, white matter disease, and hippocampal and brain volumes, independent of socioeconomic, language, education, and clinical factors. Other significant associations included general cognitive functioning with hippocampal volume. Nonsignificant, marginal associations included general cognition with WMH and brain volume; verbal memory with hippocampal volume; verbal fluency and executive function with brain volume; and processing speed with ventricle enlargement. Conclusions: Brain-cognition associations found in this study of elderly American Indians are similar to those found in other racial/ethnic populations, with processing speed comprising an especially strong correlate of cerebrovascular disease. These findings may assist future efforts to define opportunities for disease prevention, to conduct research on diagnostic and normative standards, and to guide clinical evaluation of this underserved and overburdened population. [ABSTRACT FROM AUTHOR]

Objectives: Insulin resistance is a substantial health issue for American Indians, with type 2 diabetes overrepresented in this population as compared with non-Hispanic whites. Insulin resistance and its related conditions in turn increase risk for dementia and cognitive impairment. The aim of the current study was to determine whether type 2 diabetes and insulin resistance at midlife was associated with later-life cognitive testing in a large sample of older American Indians, aged 65 and older.Methods: American Indian participants who underwent both fasting blood draw as part of the Strong Heart Study and had subsequent cognitive testing as part of the later adjunct Cerebrovascular Disease and its Consequences in American Indians study were included (n = 790). Regression models examined type 2 diabetes and impaired fasting glucose and subsequent cognitive test performance as part of a longitudinal study design. The relationship between a continuous measure of insulin resistance and later cognitive test performance was assessed using generalized estimating equations.Results: Controlling for demographic and clinical factors, verbal fluency and processing speed/working memory were significantly negatively associated with having type 2 diabetes and with insulin resistance, but not with impaired fasting glucose.Conclusion: In this sample of American Indians, type 2 diabetes at midlife was associated with subsequent lower performance on measures of executive function. These results may have important implications for future implementation of diagnostic and intervention services in this population. [ABSTRACT FROM AUTHOR]