Many Forms of Mind: Exploring Heterogeneity in Indigenous Older Adults' Cognitive Health

Background and Purpose: The number of Indigenous Older Adults (IOAs) living with Alzheimer’s Disease and Related Dementias (ADRDs) is expected to rise. Given the high costs of caring for those with ADRDs, a growth in the population of IOAs living with cognitive impairments will bring new challenges to many Indigenous communities where preventative and long-term care services for elders are chronically underfunded. The relationship between chronic stress and cognitive health represents a modifiable, and unexplored, pathway between social environments and cognitive impairment among IOAs. Moreover, the limited knowledge about the cognitive health of IOAs represents a crisis of health equity research.

Methods: This study used data from the Health and Retirement Study data to investigate cognitive health trajectories among IOAs in the United States over a 14-year period (2006-2020). Guided by minority stress theory, we modeled a robust set of psychosocial (e.g. educational quality, perceived everyday discrimination experiences), behavioral (e.g. substance use, exercise), and physiological (e.g. diabetes, hypertension, obesity) risk factors associated with cognition trajectories among 186 IOAs using mixed growth curves.

Results: O A third of IOAs reported experiencing everyday discrimination at least once per month,. They also reported high rates of other risk factors for cognitive impairment: low education, socio-economic status, physical inactivity, depression and chronic health conditions. Longitudinal analysis found that everyday discrimination was negatively associated with total cognition among IOAs but that this relationship had a modest effect size (p<0.01). As expected, we also found that higher levels of educational attainment and physical activity were positively associated with total cognition trajectories. Multiple risk factors (hypertension, diabetes, obesity, depression, and substance use) yielded significant negative associations with these quadratic models (p<0.001). Interestingly, we found that unlike the general population, men were at significantly higher risk of accelerated cognitive decline than women among this sample of IOAs (p<0.01).

Conclusions and Implications: This study has important implications for the integration of stress as a mechanism for cognitive decline and the health equity of Indigenous older adults. These findings confirmed aspects of critical race and minority stress theories. Not only have IOAs been traditionally underrepresented in cognitive health research, but few longitudinal analyses have sought to unpack the heterogeneity of global cognitive function among IOAs. These findings serve as a model not only for the integration of IOAs into future longitudinal cognitive health research, but also highlight novel risk factors among IOAs for ADRDs in later life including high-levels of everyday discrimination experiences and multiple chronic health conditions.