Mechanisms of Racial Disparities in Cognitive Aging: An Examination of Material and Psychosocial Well-Being

The Interplay of Race, Ethnicity, and Language in Caregiver Health: Insights from the National Social Life, Health, and Aging Project

Background

Recent socio-demographic shifts in the United States have underscored the growing importance of informal caregiving and raised concerns about caregivers' health and well-being. This study aims to deepen our understanding of the health dimensions of caregivers, considering their diverse backgrounds.

Objective

To examine five key health dimensions (physical, cognitive, mental, social, and sexual health) of caregivers, and to identify potential disparities based on ethnoracial and linguistic differences.

Methods

Using data from the National Social Life, Health, and Aging Project (NSHAP), this study explores the interconnections among the specified health dimensions of caregivers and their ethnoracial (Black, Hispanic, White, and others) and linguistic (Spanish, English) backgrounds, in addition to their social networks (N=1,309). Regression analysis was employed to discern the patterns and associations.

Results

The findings indicate that White caregivers generally report better physical, cognitive, and social health compared to their Black and Hispanic counterparts, but exhibit less favorable outcomes in sexual health than Hispanic caregivers. Spanish-speaking caregivers, while having lower cognitive and self-rated mental health than English-speaking caregivers, show stronger social health and greater relationship satisfaction. Notably, these correlations persist irrespective of the size of social networks, pointing to intrinsic links with health outcomes.

Conclusion

The study underscores the necessity of a comprehensive health evaluation for caregivers, acknowledging the intricate interplay between their health and various socio-demographic factors. It advocates for the development of targeted policies and interventions that address the complex health needs of caregivers, with an emphasis on their ethnoracial and linguistic contexts and social environments.

An overview of the hallmarks of cognitive aging

Although the notion of cognitive aging is commonly associated with decline in popular culture, a wealth of scientific literature shows that cognitive aging is more aptly characterized as multidirectional, such that trajectories of cognitive changes include areas of stability and growth (e.g., general knowledge) in addition to decline (e.g., episodic long-term memory). This article overviews these multidirectional trajectories, the heterogeneous factors that moderate the rate of change across individual trajectories, and the extensive literature that has investigated the most important factors, such as working memory, that constrain cognition across the adult lifespan. In light of the multidirectional nature of cognitive change, increasing research has considered methods to leverage the often-overlooked benefits of getting older to ameliorate cognitive deficits.

Race, community disadvantage, and cognitive decline: Findings from KHANDLE and STAR

INTRODUCTION

Community disadvantage is associated with late-life cognition. Few studies examine its contribution to racial disparities in cognition/cognitive change.

METHODS

Inverse probability weighted models estimated expected mean differences in cognition/cognitive change attributed to residing in less advantaged communities, defined as cohort top quintile of Area Deprivation Indices (ADI): childhood 66-100; adulthood ADI 5-99). Interactions by race tested.

RESULTS

More Black participants resided in less advantaged communities. Semantic memory would be lower if all participants had resided in less advantaged childhood (b = -0.16, 95% confidence interval [CI] = -0.30, -0.03) or adulthood (b = -0.14, 95% CI = -0.22, -0.04) communities. Race interactions indicated that, among Black participants, less advantaged childhood communities were associated with higher verbal episodic memory (interaction p-value = 0.007) and less advantaged adulthood communities were associated with lower semantic memory (interaction p-value = 0.002).

DISCUSSION

Examining racial differences in levels of community advantage and late-life cognitive decline is a critical step toward unpacking community effects on cognitive disparities.

Epigenetic age and socioeconomic status contribute to racial disparities in cognitive and functional aging between Black and White older Americans

Epigenetic age, a biological aging marker measured by DNA methylation, is a potential mechanism by which social factors drive disparities in age-related health. Epigenetic age gap is the residual between epigenetic age measures and chronological age. Previous studies showed associations between epigenetic age gap and age-related outcomes including cognitive capacity and performance on some functional measures, but whether epigenetic age gap contributes to disparities in these outcomes is unknown. We use data from the Health and Retirement Study to examine the role of epigenetic age gap in racial disparities in cognitive and functional outcomes and consider the role of socioeconomic status (SES). Epigenetic age measures are GrimAge or Dunedin Pace of Aging methylation (DPoAm). Cognitive outcomes are cross-sectional score and two-year change in Telephone Interview for Cognitive Status (TICS). Functional outcomes are prevalence and incidence of limitations performing Instrumental Activities of Daily Living (IADLs). We find, relative to White participants, Black participants have lower scores and greater decline in TICS, higher prevalence and incidence rates of IADL limitations, and higher epigenetic age gap. Age- and gender-adjusted analyses reveal that higher GrimAge and DPoAm gap are both associated with worse cognitive and functional outcomes and mediate 6-11% of racial disparities in cognitive outcomes and 19-39% of disparities in functional outcomes. Adjusting for SES attenuates most DPoAm associations and most mediation effects. These results support that epigenetic age gap contributes to racial disparities in cognition and functioning and may be an important mechanism linking social factors to disparities in health outcomes.

Evaluating interpersonal discrimination and depressive symptoms as partial mediators of the effects of education on cognition: Evidence from the Study of Healthy Aging in African Americans (STAR)

INTRODUCTION

Education is correlated with positive health outcomes, but associations are sometimes weaker among African Americans. The extent to which exposure to discrimination and depressive symptoms attenuates the education-cognition link has not been investigated.

METHODS

Study of Healthy Aging in African Americans (STAR) participants (n = 764; average age 69 years) completed the Spanish and English Neuropsychological Assessment Scales. We assessed everyday and major lifetime discrimination and depressive symptoms as mediators of education effects on cognition using G-estimation with measurement error corrections.

RESULTS

Education was correlated with greater major lifetime and everyday discrimination but lower depressive symptoms. Accounting for discrimination and depressive symptoms slightly reduced the estimated effect of education on cognition. The estimated total effect of graduate education (vs 

DISCUSSION

Education has robust effects on later-life cognition after controlling multiple mediating pathways and offsetting mechanisms.

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Key Words

• African Americans
• cognition
• depression
• discrimination
• education
• psychosocial stress

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MESH Headings

• Aged
• Humans
• Black or African American
• Cognition
• Depression/psychology
• Educational Status
• Healthy Aging
• Racism/ethnology
• Racism/psychology

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Grants

• R01 AG066132 NIA NIH HHS
• R01 AG050782 NIA NIH HHS
• RF1 AG050782 NIA NIH HHS
• P30 AG072972 NIA NIH HHS
• R00 AG073457 NIA NIH HHS

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Affiliation(s)

Dakota W. Cintron Center for Health and Community, University of California, San Francisco, San Francisco, CA Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA
Camilla Calmasini Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA
Lisa L. Barnes Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL, USA Department of Neurology, Rush University Medical Center, Chicago, IL, USA
Dan M. Mungas Department of Neurology, University of California Davis Health, Sacramento, CA, USA
Rachel A. Whitmer Department of Public Health Sciences, University of California Davis, Davis, CA, USA Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA
Chloe W. Eng Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA
Paola Gilsanz Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA
Kristen M. George Department of Neurology, University of California Davis Health, Sacramento, CA, USA Department of Public Health Sciences, University of California Davis, Davis, CA, USA
Rachel Peterson Department of Neurology, University of California Davis Health, Sacramento, CA, USA Department of Public Health Sciences, University of California Davis, Davis, CA, USA
M. Maria Glymour Center for Health and Community, University of California, San Francisco, San Francisco, CA Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA

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Expanding the scope of health disparities research in Alzheimer's disease and related dementias: Recommendations from the "Leveraging Existing Data and Analytic Methods for Health Disparities Research Related to Aging and Alzheimer's Disease and Related Dementias" Workshop Series

Topics discussed at the "Leveraging Existing Data and Analytic Methods for Health Disparities Research Related to Aging and Alzheimer's Disease and Related Dementias" workshop, held by Duke University and the Alzheimer's Association with support from the National Institute on Aging, are summarized.  Ways in which existing data resources paired with innovative applications of both novel and well-known methodologies can be used to identify the effects of multi-level societal, community, and individual determinants of race/ethnicity, sex, and geography-related health disparities in Alzheimer's disease and related dementia are proposed.  Current literature on the population analyses of these health disparities is summarized with a focus on identifying existing gaps in knowledge, and ways to mitigate these gaps using data/method combinations are discussed at the workshop.  Substantive and methodological directions of future research capable of advancing health disparities research related to aging are formulated.

Pathways explaining racial/ethnic and socio-economic disparities in incident all-cause dementia among older US adults across income groups

Differential racial and socioeconomic disparities in dementia incidence across income groups and their underlying mechanisms remain largely unknown. A retrospective cohort study examining all-cause dementia incidence across income groups was conducted linking third National Health and Nutrition Examination Surveys (NHANES III) to Centers for Medicare and Medicaid Services-Medicare data over ≤26 y of follow-up (1988-2014). Cox regression and generalized structural equations models (GSEM) were constructed among adults aged≥60 y at baseline (N = 4,592). Non-Hispanic Black versus White (NHW) adults had higher risk of dementia in age and sex-adjusted Cox regression models (HR = 1.34, 95%CI: 1.15-1.55, P < 0.001), an association that was attenuated in the SES-adjusted model (HR = 1.15, 95%CI: 1.01-1.34, P = 0.092). SES was inversely related to dementia risk overall (per Standard Deviation, HR = 0.80, 95% CI:0.69-0.92, P = 0.002, Model 2), mainly within the middle-income group. Within the lowest and middle-income groups and in socio-economic status (SES)-adjusted models, Mexican American participants were at lower all-cause dementia risk compared with their NHW counterparts. GSEM models further detected 3 pathways explaining >55% of the total effect of SES on dementia risk (Total effect = -0.160 ± 0.067, p = 0.022), namely SES→LIFESTYLE→DEMENTIA (Indirect effect (IE) = -0.041 ± 0.014, p = 0.004), SES→LIFESTYLE→COGN→DEMENTIA (IE = -0.006 ± 0.001, p < 0.001), SES→COGN→DEMENTIA(IE = -0.040 ± 0.008, p < 0.001), with the last two remaining significant or marginally significant in the uppermost income groups. Diet and social support were among key lifestyle factors involved in socio-economic disparities in dementia incidence. We provide evidence for modifiable risk factors that may delay dementia onset differentially across poverty-income ratio groups, underscoring their importance for future observational and intervention studies.

Satisfaction With Life and Risk of Dementia: Findings From the Korean Longitudinal Study of Aging

OBJECTIVES

Life satisfaction is increasingly viewed as an asset associated with better general health, but its association with cognitive health and risk of dementia is less examined. We tested the hypothesis that higher life satisfaction would be associated with lower risk of dementia.

METHODS

Participants were a nationally representative sample of adults (n = 8,021; age range: 45-93 years) from the Korean Longitudinal Study of Aging assessed every 2 years for up to 12 years. Multilevel modeling analysis examined whether life satisfaction is associated with cognitive functioning and decline. The primary analysis used Cox regression to examine the association between baseline life satisfaction and risk of incident dementia.

RESULTS

Between-person differences and within-person changes in life satisfaction were associated with cognitive functioning, but life satisfaction was unrelated to the rate of cognitive decline. Higher life satisfaction was also associated with lower risk of dementia, even after accounting for demographic factors, depressive symptoms, cardiovascular and functional risk factors, health behaviors, and social contact.

DISCUSSION

Satisfaction with life may function as a positive psychological resource for maintaining cognitive functioning and protecting against the risk of dementia.

Income, wealth, and Black-White disparities in cognition

We investigated the contributions of income and wealth (beyond education) to Black-White disparities in cognition and evaluated whether the role of socioeconomic status (SES) varies by age. Based on data from a national survey of Americans (aged 23-94), we used regression models to quantify the overall racial disparities in episodic memory, executive function, and overall cognition, adjusted for sex and age. Potential mediators (i.e., measures of childhood environment, educational attainment, marital status, occupation, income, and wealth) were added in subsequent models. The age- and sex-adjusted Black-White differential in overall cognitive function was around one standard deviation (SD) between ages 25 and 50, but declined to 0.6 SD by age 80. Executive function followed a similar pattern, but the racial disparity in episodic memory declined more rapidly between ages 35 (0.7 SD) and 80 (0.2 SD). Childhood environment and the respondent's educational attainment accounted for 20-25% of the racial disparities in overall cognition. The incremental contribution of household income was small (1-5%). Although wealth had only a small effect at younger ages, the contribution grew with age. Wealth was much more important than income in explaining Black-White disparities in cognition at older ages. Childhood environment, marital status, and SES (including wealth) accounted for one-third of the racial disparity in overall cognition at ages 35-65, but an even greater share at age 80. Our study is the first to demonstrate that, with increasing age, wealth explains more of the Black-White disparity in cognition. A widening racial gap in wealth and the disproportionate financial impact of the Great Recession and the COVID-19 pandemic on minorities do not bode well for Black-White differentials in cognition. Working-age Americans suffered the brunt of the economic impact of those events; the impact on cognition may increase as those cohorts grow older.

Race Inequity in School Attendance Across the Jim Crow South and Its Implications for Black-White Disparities in Trajectories of Cognitive Function Among Older Adults

OBJECTIVES

Although education is a key determinant of cognitive function, its role in determining Black-White disparities in cognitive function is unclear. This may be due, in part, to data limitations that have made it difficult to account for systemic educational inequities in the Jim Crow South experienced by older cohorts, including differences in the number of days Black students attended school compared to their White counterparts or Black peers in better-funded southern states. We determine if accounting for differential rates of school attendance across race, years, and states in the Jim Crow South better illuminates Black-White disparities in trajectories of cognitive function.

METHODS

We linked historical state-level data on school attendance from the 1919/1920 to 1953/1954 Biennial Surveys of Education to the Health and Retirement Study, a nationally representative, longitudinal study of U.S. adults older than age 50. We restricted our sample to Black and White older adults who attended school in the Jim Crow South and began primary school in/after 1919/1920 and completed primary/secondary school by 1953/1954 (n = 4,343). We used linear mixed models to estimate trajectories of total cognitive function, episodic memory, and working memory.

RESULTS

Self-reported years of schooling explained 28%-33% of the Black-White disparity in level of cognitive function, episodic memory, and working memory. Duration of school, a measure that accounted for differential rates of school attendance, explained 41%-55% of the Black-White disparity in these outcomes.

DISCUSSION

Our study highlights the importance of using a more refined measure of schooling for understanding the education-cognitive health relationship.

What Can Cognitive Science Do for People?

The critical question for cognitive scientists is what does cognitive science do, if anything, for people? Cognitive science is primarily concerned with human cognition but has fallen short in continuously and critically assessing the who in human cognition. This complacency in a world where white supremacist and patriarchal structures leave cognitive science in the unfortunate position of potentially supporting those structures. We take it that many cognitive scientists operate on the assumption that the study of human cognition is both interesting and important. We want to invoke that importance to note that cognitive scientists must continue to work to show how the field is useful to all of humanity and reflects a humanity that is not white by default. We wonder how much the field has done, and can do, to show that it is useful not only in the sense that we might make connections with researchers in other fields, win grants and write papers, even of the highest quality, but useful in some material way to the billions of non-cognitive scientists across the globe.

Does a Cancer Diagnosis in Mid-to-Later Life Modify Racial Disparities in Memory Aging?

BACKGROUND

It is unknown whether an incident cancer diagnosis differentially impacts acute and long-term memory aging between older White and Black Americans.

METHODS

Incident cancer diagnoses and memory (immediate and delayed recall, combined with proxy-reported memory) were assessed at biennial study interviews in the US Health and Retirement Study (N=14,235, 1998-2016). We used multivariable segmented linear mixed-effects models to evaluate the rate of change in standardized memory score (SD/decade) in the years before, acutely at the time of, and in the years following an incident cancer diagnosis, compared to cancer-free adults, by race.

RESULTS

Black participants experienced faster memory decline than White participants (cancer-free group: -1.211 vs. -1.077; P<0.0001). An incident cancer diagnosis was associated with an acute memory drop in White, but not Black participants (-0.065 vs. 0.024; P<0.0001). However, White cancer survivors experienced slower memory decline than cancer-free White adults before and after diagnosis, but this memory advantage was not observed among Black cancer survivors.

CONCLUSIONS

Racial disparities in memory aging are not modified by an incident cancer diagnosis. The acute cancer-related memory decline and long-term memory advantage experienced by White, but not Black, cancer survivors relative to cancer-free older adults, requires further investigation.