Measuring Cognitive Health in Ethnically Diverse Older Adults

Abstract

Objectives: Understanding racial/ethnic disparities in late-life cognitive health is a public health imperative. We used baseline data from the Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) study to examine how age, education, gender, and clinical diagnosis, a proxy for brain health, are associated with cross-sectional measures of cognition in diverse racial/ethnic groups.

Methods: Comprehensive measures of cognition were obtained using the Spanish and English Neuropsychological Assessment Scales and the National Institutes of Health Toolbox Cognitive Health Battery in a sample of 1,695 KHANDLE participants (Asians 24%, Blacks 26%, Latinos 20%, Whites 29%). A 25% random subsample was clinically evaluated and diagnosed with normal cognition, mild cognitive impairment (MCI), or dementia. Cognitive test scores were regressed on core demographic variables and diagnosis in the combined sample and in multiple group analyses stratified by racial/ethnic group.

Results: Race/ethnicity and education were variably associated with test scores with strongest associations with tests of vocabulary and semantic memory. Older age was associated with poorer performance on all measures, and gender differences varied across cognitive tests. Clinical diagnosis of MCI or dementia was associated with average decrements in test scores that ranged from -0.41 to -0.84 SD, with largest differences on tests of executive function and episodic memory. With few exceptions, associations of demographic variables and clinical diagnosis did not differ across racial/ethnic groups.

Discussion: The robust associations of cognitive test results with clinical diagnosis independent of core demographic variables and race/ethnicity support the validity of cognitive tests as indicators for brain health in diverse older adults.

Keywords: Cognition; Cross-cultural differences; Epidemiology; Neuropsychology.

Figure 1.

Associations of core demographic variables with SENAS and NIHTB cognition measures. Colored bars (with black 95% confidence interval bars) represent effect estimates for cognitive test scores regressed on age, education, and gender in the full sample. Effects for age and education show the average impact in standard deviation units of a 1 year increment in age or education. The effects for gender show how the average scores for males differ from those for females. Results are from models that included all core demographic variables as independent variables. NIHTB = NIH Toolbox; SENAS = Spanish and English Neuropsychological Assessment Scales.

Figure 2.

Associations of clinical diagnosis with cognitive test scores in Random Selection subgroup. Colored bars (with black 95% confidence interval bars) show the magnitude of average differences between cognitively impaired individuals (MCI or dementia) in comparison with cognitively normal individuals. Results are from models that included all core demographic variables and indicators for racial/ethnic group as independent variables. MCI = mild cognitive impairment; NIHTB = NIH Toolbox; SENAS = Spanish and English Neuropsychological Assessment Scales.