Association of Racial Residential Segregation Throughout Young Adulthood and Cognitive Performance in Middle-aged Participants in the CARDIA Study

Neighborhood Racial and Ethnic Segregation and the Risk of Dementia in Older Adults Living with Kidney Failure

Key Points

Background

Dementia disproportionately affects older minoritized adults with kidney failure. To better understand the mechanism of this disparity, we studied the role of racial and ethnic segregation (segregation hereafter), i.e., a form of structural racism recently identified as a mechanism in numerous other health disparities.

Methods

We identified 901,065 older adults (aged ≥55 years) with kidney failure from 2003 to 2019 using the United States Renal Data System. We quantified dementia risk across tertiles of residential neighborhood segregation score using cause-specific hazard models, adjusting for individual- and neighborhood-level factors. We included an interaction term to quantify the differential effect of segregation on dementia diagnosis by race and ethnicity.

Results

We identified 79,851 older adults with kidney failure diagnosed with dementia between 2003 and 2019 (median follow-up: 2.2 years). Compared with those in low-segregation neighborhoods, older adults with kidney failure in high-segregation neighborhoods had a 1.63-fold (95% confidence interval [CI], 1.60 to 1.66) higher risk of dementia diagnosis, an association that differed by race and ethnicity (Asian: adjusted hazard ratio [aHR] = 1.26, 95% CI, 1.15 to 1.38; Black: aHR = 1.66, 95% CI, 1.61 to 1.71; Hispanic: aHR = 2.05, 95% CI, 1.93 to 2.18; White: aHR = 1.59, 95% CI, 1.55 to 1.64; P interaction < 0.001). Notably, older Asian (aHR = 1.76; 95% CI, 1.64 to 1.89), Black (aHR = 2.65; 95% CI, 2.54 to 2.77), Hispanic (aHR = 2.15; 95% CI, 2.04 to 2.26), and White (aHR = 2.20; 95% CI, 2.09 to 2.31) adults with kidney failure residing in minority-predominant high-segregation neighborhoods had a higher risk of dementia diagnosis compared with older White adults with kidney failure in White-predominant high-segregation neighborhoods. Moreover, older adults with kidney failure receiving care at dialysis facilities located in high-segregation neighborhoods also experienced a higher risk of dementia diagnosis (aHR = 1.53; 95% CI, 1.50 to 1.56); this association differed by race and ethnicity (P interaction < 0.001).

Conclusions

Residing in or receiving care at dialysis facilities located in high-segregation neighborhoods was associated with a higher risk of dementia diagnosis among older individuals with kidney failure, particularly minoritized individuals.

African American patients have a higher probability of cognitive impairment after incident stroke: An analysis of national electronic health record data

BACKGROUND

Cognitive impairment (CI) and stroke are diseases with significant disparities in race and geography. Post stroke cognitive impairment (PSCI) can be as high as 15-70 % but few studies have utilized large administrative or electronic health records (EHR) to evaluate trends in PSCI. We utilized an EHR database to evaluate for disparities in PSCI in a large sample of patients after first recorded stroke to evaluate for disparities in race.

METHODS

This is a retrospective cohort analysis of Cerner Health Facts® EHR database, which is comprised of EHR data from hundreds of hospitals/clinics in the US from 2009-2018. We evaluated patients ≥40 years of age with a first time ischemic stroke (IS) diagnosis for PSCI using ICD9/10 codes for both conditions. Patients with first stroke in the Cerner database and no pre-existing cognitive impairment were included, we compared hazard ratios for developing PSCI for patient characteristics RESULTS: A total of 150,142 IS patients with follow-up data and no pre-existing evidence of CI were evaluated. Traditional risk factors of age, female sex, kidney injury, hypertension, and hyperlipidemia were associated with PSCI. Only African American stroke survivors had a higher probability of developing PSCI compared to White survivors (HR 1.347, 95 % CI (1.270, 1.428)) and this difference was most prominent in the South. Among those to develop PSCI, median time to documentation was 1.8 years in African American survivors.

CONCLUSION

In a large national database, African American stroke survivors had a higher probability of PSCI five years after stroke than White survivors.

2024 Alzheimer's disease facts and figures

This article describes the public health impact of Alzheimer's disease (AD), including prevalence and incidence, mortality and morbidity, use and costs of care and the ramifications of AD for family caregivers, the dementia workforce and society. The Special Report discusses the larger health care system for older adults with cognitive issues, focusing on the role of caregivers and non-physician health care professionals. An estimated 6.9 million Americans age 65 and older are living with Alzheimer's dementia today. This number could grow to 13.8 million by 2060, barring the development of medical breakthroughs to prevent or cure AD. Official AD death certificates recorded 119,399 deaths from AD in 2021. In 2020 and 2021, when COVID-19 entered the ranks of the top ten causes of death, Alzheimer's was the seventh-leading cause of death in the United States. Official counts for more recent years are still being compiled. Alzheimer's remains the fifth-leading cause of death among Americans age 65 and older. Between 2000 and 2021, deaths from stroke, heart disease and HIV decreased, whereas reported deaths from AD increased more than 140%. More than 11 million family members and other unpaid caregivers provided an estimated 18.4 billion hours of care to people with Alzheimer's or other dementias in 2023. These figures reflect a decline in the number of caregivers compared with a decade earlier, as well as an increase in the amount of care provided by each remaining caregiver. Unpaid dementia caregiving was valued at $346.6 billion in 2023. Its costs, however, extend to unpaid caregivers' increased risk for emotional distress and negative mental and physical health outcomes. Members of the paid health care and broader community-based workforce are involved in diagnosing, treating and caring for people with dementia. However, the United States faces growing shortages across different segments of the dementia care workforce due to a combination of factors, including the absolute increase in the number of people living with dementia. Therefore, targeted programs and care delivery models will be needed to attract, better train and effectively deploy health care and community-based workers to provide dementia care. Average per-person Medicare payments for services to beneficiaries age 65 and older with AD or other dementias are almost three times as great as payments for beneficiaries without these conditions, and Medicaid payments are more than 22 times as great. Total payments in 2024 for health care, long-term care and hospice services for people age 65 and older with dementia are estimated to be $360 billion. The Special Report investigates how caregivers of older adults with cognitive issues interact with the health care system and examines the role non-physician health care professionals play in facilitating clinical care and access to community-based services and supports. It includes surveys of caregivers and health care workers, focusing on their experiences, challenges, awareness and perceptions of dementia care navigation.

Large-scale Deep Proteomic Analysis in Alzheimer's Disease Brain Regions Across Race and Ethnicity

Introduction

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease, yet our comprehension predominantly relies on studies within the non-Hispanic White (NHW) population. Here we aimed to provide comprehensive insights into the proteomic landscape of AD across diverse racial and ethnic groups.

Methods

Dorsolateral prefrontal cortex (DLPFC) and superior temporal gyrus (STG) brain tissues were donated from multiple centers (Mayo Clinic, Emory University, Rush University, Mt. Sinai School of Medicine) and were harmonized through neuropathological evaluation, specifically adhering to the Braak staging and CERAD criteria. Among 1105 DLPFC tissue samples (998 unique individuals), 333 were from African American donors, 223 from Latino Americans, 529 from NHW donors, and the rest were from a mixed or unknown racial background. Among 280 STG tissue samples (244 unique individuals), 86 were African American, 76 Latino American, 116 NHW and the rest were mixed or unknown ethnicity. All tissues were uniformly homogenized and analyzed by tandem mass tag mass spectrometry (TMT-MS).

Results

As a Quality control (QC) measure, proteins with more than 50% missing values were removed and iterative principal component analysis was conducted to remove outliers within brain regions. After QC, 9,180 and 9,734 proteins remained in the DLPC and STG proteome, respectively, of which approximately 9,000 proteins were shared between regions. Protein levels of microtubule-associated protein tau (MAPT) and amyloid-precursor protein (APP) demonstrated AD-related elevations in DLPFC tissues with a strong association with CERAD and Braak across racial groups. APOE4 protein levels in brain were highly concordant with APOE genotype of the individuals.

Discussion

This comprehensive region resolved large-scale proteomic dataset provides a resource for the understanding of ethnoracial-specific protein differences in AD brain.

"Hang Ups, Let Downs, Bad Breaks, Setbacks": Impact of Structural Socioeconomic Racism and Resilience on Cognitive Change Over Time for Persons Racialized as Black

Introduction

Older adults racialized as Black experience higher rates of dementia than those racialized as White. Structural racism produces socioeconomic challenges, described by artist Marvin Gaye as "hang ups, let downs, bad breaks, setbacks" that likely contribute to dementia disparities. Robust dementia literature suggests socioeconomic factors may also be key resiliencies.

Methods

We linked state-level data reflecting the racialized landscape of economic opportunity across the 20th Century from the U.S. Census (1930-2010) with individual-level data on cognitive outcomes from the U.S. Health and Retirement Study participants racialized as Black. A purposive sample of participants born after the Brown v. Board ruling (born 1954-59) were selected who completed the modified Telephone Interview for Cognitive Status between 2010 and 2020 (N=1381). We tested associations of exposure to structural racism and resilience before birth, and during childhood, young-adulthood, and midlife with cognitive trajectories in mid-late life using mixed-effects regression models.

Results

Older adults born in places with higher state-level structural socioeconomic racism experienced a more rapid cognitive decline in later life compared to those with lower levels of exposure. In addition, participants born in places with higher levels of state-level structural socioeconomic resilience experienced slower cognitive change over time than their counterparts.

Discussion

These findings reveal the impact of racist U.S. policies enacted in the past that influence cognitive health over time and dementia risk later in life.

Promoting diverse perspectives: Addressing health disparities related to Alzheimer's and all dementias

Dementia research lacks appropriate representation of diverse groups who often face substantial adversity and greater risk of dementia. Current research participants are primarily well-resourced, non-Hispanic White, cisgender adults who live close to academic medical centers where much of the research is based. Consequently, the field faces a knowledge gap about Alzheimer's-related risk factors in those other groups. The Alzheimer's Association hosted a virtual conference on June 14-16, 2021, supported in part by the National Institute on Aging (R13 AG072859-01), focused on health disparities. The conference was held entirely online and consisted of 2 days of core programming and a day of focused meetings centered on American Indian and Alaska Natives and on LGBTQIA+ populations. Over 1300 registrants attended discussions focused on the structural and systemic inequities experienced across diverse groups, as well as ways to investigate and address these inequities.

Systematic Review of Longitudinal Evidence and Methodologies for Research on Neighborhood Characteristics and Brain Health

Objective: Synthesize longitudinal research evaluating neighborhood environments and cognition to identify methodological approaches, findings, and gaps. Methods: Included studies evaluated associations between neighborhood and cognition longitudinally among adults >45 years (or mean age of 65 years) living in developed nations. We extracted data on sample characteristics, exposures, outcomes, methods, overall findings, and assessment of disparities. Results: Forty studies met our inclusion criteria. Most (65%) measured exposure only once and a majority focused on green space and/or blue space (water), neighborhood socioeconomic status, and recreation/physical activity facilities. Similarly, over half studied incident impairment, cognitive function or decline (70%), with one examining MRI (2.5%) or Alzheimer's disease (7.5%). While most studies used repeated measures analysis to evaluate changes in the brain health outcome (51%), many studies did not account for any type of correlation within neighborhoods (35%). Less than half evaluated effect modification by race/ethnicity, socioeconomic status, and/or sex/gender. Evidence was mixed and dependent on exposure or outcome assessed. Conclusion: Although longitudinal research evaluating neighborhood and cognitive decline has expanded, gaps remain in types of exposures, outcomes, analytic approaches, and sample diversity.

A Scoping Review of Neighborhoods and Cognitive Health Disparities Among US Midlife and Older Adults

Objectives: The neighborhood environment may be an important determinant of racial/ethnic disparities in cognitive function. To understand how neighborhoods are linked to cognition across racial/ethnic groups, this scoping review organizes research investigating relationships between multiple neighborhood domains and cognitive function in diverse samples of US midlife and older adults. Methods: PubMed/MEDLINE, Web of Science, and CAHL were used to extract quantitative disparities-focused studies (n = 17) that included US adults ages 50+, racial/ethnic minoritized populations, cognitive dependent variable(s), and neighborhood-level independent variable(s) published from January 2010 to October 2021. Results: Studies demonstrate variation within and between racial/ethnic groups in how neighborhood factors are associated with cognition. Economically and socially advantaged neighborhoods were associated with better cognition. Findings were mixed for built and neighborhood composition measures. Discussion: More research with greater racial/ethnic representation is needed to disentangle which aspects of the neighborhood are most salient for specific cognitive function domains across diverse populations.

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.

Building towards an adolescent neural urbanome: Expanding environmental measures using linked external data (LED) in the ABCD study

Many recent studies have demonstrated that environmental contexts, both social and physical, have an important impact on child and adolescent neural and behavioral development. The adoption of geospatial methods, such as in the Adolescent Brain Cognitive Development (ABCD) Study, has facilitated the exploration of many environmental contexts surrounding participants' residential locations without creating additional burdens for research participants (i.e., youth and families) in neuroscience studies. However, as the number of linked databases increases, developing a framework that considers the various domains related to child and adolescent environments external to their home becomes crucial. Such a framework needs to identify structural contextual factors that may yield inequalities in children's built and natural environments; these differences may, in turn, result in downstream negative effects on children from historically minoritized groups. In this paper, we develop such a framework - which we describe as the "adolescent neural urbanome" - and use it to categorize newly geocoded information incorporated into the ABCD Study by the Linked External Data (LED) Environment & Policy Working Group. We also highlight important relationships between the linked measures and describe possible applications of the Adolescent Neural Urbanome. Finally, we provide a number of recommendations and considerations regarding the responsible use and communication of these data, highlighting the potential harm to historically minoritized groups through their misuse.

Integrative blood-based characterization of oxidative mitochondrial DNA damage variants implicates Mexican American's metabolic risk for developing Alzheimer's disease

Alzheimer's Disease (AD) continues to be a leading cause of death in the US. As the US aging population (ages 65 +) expands, the impact will disproportionately affect vulnerable populations, e.g., Hispanic/Latino population, due to their AD-related health disparities. Age-related regression in mitochondrial activity and ethnic-specific differences in metabolic burden could potentially explain in part the racial/ethnic distinctions in etiology that exist for AD. Oxidation of guanine (G) to 8-oxo-guanine (8oxoG) is a prevalent lesion and an indicator of oxidative stress and mitochondrial dysfunction. Damaged mtDNA (8oxoG) can serve as an important marker of age-related systemic metabolic dysfunction and upon release into peripheral circulation may exacerbate pathophysiology contributing to AD development and/or progression. Analyzing blood samples from Mexican American (MA) and non-Hispanic White (NHW) participants enrolled in the Texas Alzheimer's Research & Care Consortium, we used blood-based measurements of 8oxoG from both buffy coat PBMCs and plasma to determine associations with population, sex, type-2 diabetes, and AD risk. Our results show that 8oxoG levels in both buffy coat and plasma were significantly associated with population, sex, years of education, and reveal a potential association with AD. Furthermore, MAs are significantly burdened by mtDNA oxidative damage in both blood fractions, which may contribute to their metabolic vulnerability to developing AD.

Recommendations on Social Determinants of Health in Neurologic Disease

Social determinants of health (SDOH) are increasingly recognized as important drivers of inequities in neurologic disease and outcomes. However, our understanding of the biopsychosocial mechanisms by which SDOH affect neurologic disease remains in its infancy. The most robust epidemiologic research has been on the associations between education, schooling, and place-based social determinants on cognition, dementia, and cerebrovascular disease later in life. Further research is needed to more deeply understand the complex interplay of SDOH on neurologic disease. Few SDOH screening tools have been validated in populations with neurologic disease. In addition, comparison across studies and populations is hampered by lack of standardized common data elements. Experiences of populations historically underrepresented in research should be centered in future research studies, and changes should be made in recruitment expectations and measurement choices. For research on inequities, it is critical to support and incentivize institutional infrastructure to foster meaningful engagement with populations affected by research. Finally, it remains to be seen whether individual-level health or behavioral interventions or place-level, systemic or policy interventions to reduce population burden will be most effective in reducing inequities in neurologic disease and outcomes. Although numerous clinical trials have focused on addressing downstream SDOH such as health literacy and health behaviors (e.g., medication adherence, physical activity, diet), few have addressed upstream, structural determinants which may have a more profound impact on addressing inequities in neurologic disease. Ultimately, further research is needed to determine which specific SDOH should be targeted and how, when, and by whom they should be addressed to improve neurologic outcomes.

Self-reported experiences of discrimination and incident dementia

INTRODUCTION

Discrimination negatively impacts health and may contribute to racial/ethnic disparities in dementia risk.

METHODS

Experiences of lifetime and everyday discrimination were assessed among 6509 Multi-Ethnic Study of Atherosclerosis (MESA) participants. We assessed the association of discrimination with incidence of dementia including adjustment for important risk factors, cohort attrition, and we assessed for effect modification by race/ethnicity.

RESULTS

Prevalence of any lifetime discrimination in MESA was 42%, highest among Black adults (72%). Over a median 15.7 years of follow-up, there were 466 incident cases of dementia. Lifetime discrimination, but not everyday discrimination, was associated with incident dementia (Wald p = 0.03). Individuals reporting lifetime discrimination in ≥2 domains (compared to none) had greater risk for dementia (hazard ratio: 1.40; 95%: 1.08, 1.82) after adjustment for sociodemographic, clinical, and behavioral risk factors. Associations did not differ by race/ethnicity.

CONCLUSIONS

These findings demonstrate an association of greater experiences of lifetime discrimination with incident dementia.

Decomposing interaction and mediating effects of race/ethnicity and circulating blood levels of cystatin C on cognitive status in the United States health and retirement study

Background and objectives

Elevated circulating cystatin C is associated with cognitive impairment in non-Hispanic Whites, but its role in racial disparities in dementia is understudied. In a nationally representative sample of older non-Hispanic White, non-Hispanic Black, and Hispanic adults in the United States, we use mediation-interaction analysis to understand how racial disparities in the cystatin C physiological pathway may contribute to racial disparities in prevalent dementia.

Methods

In a pooled cross-sectional sample of the Health and Retirement Study (n = 9,923), we employed Poisson regression to estimate prevalence ratios and to test the relationship between elevated cystatin C (>1.24 vs. ≤1.24 mg/L) and impaired cognition, adjusted for demographics, behavioral risk factors, other biomarkers, and chronic conditions. Self-reported racialized social categories were a proxy measure for exposure to racism. We calculated additive interaction measures and conducted four-way mediation-interaction decomposition analysis to test the moderating effect of race/ethnicity and mediating effect of cystatin C on the racial disparity.

Results

Overall, elevated cystatin C was associated with dementia (prevalence ratio [PR] = 1.2; 95% CI: 1.0, 1.5). Among non-Hispanic Black relative to non-Hispanic White participants, the relative excess risk due to interaction was 0.7 (95% CI: -0.1, 2.4), the attributable proportion was 0.1 (95% CI: -0.2, 0.4), and the synergy index was 1.1 (95% CI: 0.8, 1.8) in a fully adjusted model. Elevated cystatin C was estimated to account for 2% (95% CI: -0, 4%) for the racial disparity in prevalent dementia, and the interaction accounted for 8% (95% CI: -5, 22%). Analyses for Hispanic relative to non-white participants suggested moderation by race/ethnicity, but not mediation.

Discussion

Elevated cystatin C was associated with dementia prevalence. Our mediation-interaction decomposition analysis suggested that the effect of elevated cystatin C on the racial disparity might be moderated by race/ethnicity, which indicates that the racialization process affects not only the distribution of circulating cystatin C across minoritized racial groups, but also the strength of association between the biomarker and dementia prevalence. These results provide evidence that cystatin C is associated with adverse brain health and this effect is larger than expected for individuals racialized as minorities had they been racialized and treated as non-Hispanic White.

Design of the think PHRESH longitudinal cohort study: Neighborhood disadvantage, cognitive aging, and alzheimer's disease risk in disinvested, black neighborhoods

BACKGROUND

Black Americans have disproportionately higher rates and earlier onset of Alzheimer's disease and related dementias (ADRD) relative to White Americans. We currently lack a comprehensive understanding of how the lived experience and broader societal factors, including cumulative exposure to structural racism and the mechanisms underlying the risks, may contribute to elevated ADRD risk in Black Americans.

METHODS

The Think PHRESH study builds on existing, community-based research infrastructure, from the ongoing Pittsburgh Hill/Homewood Research on Neighborhood Change and Health (PHRESH) studies, to examine the contributions of dynamic neighborhood socioeconomic conditions across the lifecourse to cognitive outcomes in mid- and late-life adults living in two historically disinvested, predominantly Black communities (anticipated n = 1133). This longitudinal, mixed-methods study rests on the premise that neighborhood racial segregation and subsequent disinvestment contributes to poor cognitive outcomes via factors including (a) low access to educational opportunities and (b) high exposure to race- and socioeconomically-relevant stressors, such as discrimination, trauma, and adverse childhood events. In turn, these cumulative exposures foster psychological vigilance in residents, leading to cardiometabolic dysregulation and sleep disruption, which may mediate associations between neighborhood disadvantage and ADRD risk. This premise recognizes the importance of potential protective factors that may promote cognitive health, including neighborhood social cohesion, safety, and satisfaction. The proposed study will leverage our existing longitudinal data on risk/protective factors and biobehavioral mediators and will include: (1) up to three waves of cognitive assessments in participants ages 50 years + and one assessment in participants ages 35-49 years; clinical adjudication of ADRD will be completed in participants who are 50+, (2) extensive surveys of risk and protective factors, (3) two assessments of blood pressure and objectively measured sleep, (4) a comprehensive assessment of life and residential history; and (5) two rounds of in-depth qualitative interviews to reveal lifecourse opportunities and barriers experienced by Black Americans in achieving optimal cognitive health in late life.

DISCUSSION

Understanding how structural racism has influenced the lived experience of Black Americans, including dynamic changes in neighborhood conditions over time, is critical to inform multi-level intervention and policy efforts to reduce pervasive racial and socioeconomic disparities in ADRD.

Racial Differences in Employment and Poverty Histories and Health in Older Age

INTRODUCTION

Black Americans encounter more barriers in the job market and earn less than White Americans. However, the extent to which racial disparities in employment and poverty histories impact health is not fully understood. This study characterized employment‒poverty histories for Black and White middle-aged adults and examined their association with health.

METHODS

Respondents born in 1948-1953 and enrolled in the 2004 Health and Retirement Study (N_Black=555, N_White=2,209) were included. Sequence analysis grouped respondents with similar employment‒poverty trajectories from 2004 to 2016, and confounder-adjusted regression analyses estimated the associations between these trajectories and health in 2018. Analyses were conducted in 2021-2022.

RESULTS

More than 23% of Black respondents experienced both employment and poverty fluctuations, including bouts of extreme poverty (<50% of the federal poverty threshold), whereas no trajectory for White respondents included extreme poverty. Adversities in employment‒poverty were associated with worse health. For example, among Black respondents, those who experienced both employment and poverty fluctuations had worse cognition than those employed and not poor (β= -0.55 standardized units, 95% CI= -0.81, -0.30). Similarly, among White respondents, those who experienced employment fluctuations had worse cognition than those employed (β= -0.35, 95% CI= -0.46, -0.24). Notably, the employed and not poor trajectory was associated with worse survival among Black respondents than among White respondents.

CONCLUSIONS

Employment fluctuations were associated with worse health, especially cognitive function, where the association was stronger among Black Americans who experienced both employment fluctuations and poverty. Findings highlight the importance of enhancing employment stability and of antipoverty programs, especially for Black Americans.

Associations of Religious Service Attendance With Cognitive Function in Midlife: Findings From The CARDIA Study

OBJECTIVES

Growing evidence suggests that religiosity is an important social determinant of health, including cognitive health. Yet most prior work focused on older adults or was conducted in racially and denominationally homogeneous regional samples. This study investigates the association of religious service attendance in midlife with cognitive function later in midlife.

METHODS

Using data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, a racially and geographically diverse prospective cohort study, we explored the association of religious service attendance in midlife with cognitive function 5 years later. Cognitive function was measured using four cognitive tests administered by CARDIA technicians. Multivariable linear regression was used for analyses. Primary analyses controlled for sociodemographics, physical health, depression, and prior religious involvement. Sensitivity analyses additionally controlled for baseline cognition and social support.

RESULTS

Our study population included 2,716 participants (57.2% female, 44.9% Black, and mean age 50). In primary analyses, attending services more than weekly (compared to never) in midlife was associated with better global cognition (β = 0.14 standard deviations, 95% [confidence interval] CI = 0.02, 0.26) and verbal memory (β = 0.17 standard deviations, 95% CI = 0.04, 0.30), but not with processing speed (β = 0.04 standard deviations, 95% CI = -0.08, 0.16). A reverse association was observed with executive function (β = -0.16 standard deviations, 95% CI = -0.30, -0.02). Most findings persisted in analyses accounting for loss to follow-up via inverse probability weighting.

DISCUSSION

Our findings suggest that frequent involvement in religious services at midlife is associated with better global cognition and verbal memory but worse executive function. There was no association with processing speed.

Neighborhood segregation and cognitive change: Multi-Ethnic Study of Atherosclerosis

INTRODUCTION

We investigated associations between neighborhood racial/ethnic segregation and cognitive change.

METHODS

We used data (n = 1712) from the Multi-Ethnic Study of Atherosclerosis. Racial/ethnic segregation was assessed using Getis-Ord (Gi*) z-scores based on American Community Survey Census tract data (higher Gi* = greater spatial clustering of participant's race/ethnicity). Global cognition and processing speed were assessed twice, 6 years apart. Adjusted multilevel linear regression tested associations between Gi* z-scores and cognition. Effect modification by race/ethnicity, income, education, neighborhood socioeconomic status, and neighborhood social support was tested.

RESULTS

Participants were on average 67 years old; 43% were White, 11% Chinese, 29% African American/Black, 17% Hispanic; 40% had high neighborhood segregation (Gi* > 1.96). African American/Black participants with greater neighborhood segregation had greater processing speed decline in stratified analyses, but no interactions were significant.

DISCUSSION

Segregation was associated with greater processing speed declines among African American/Black participants. Additional follow-ups and comprehensive cognitive batteries may further elucidate these findings.

HIGHLIGHTS

A study of neighborhood racial/ethnic segregation and change in cognition. Study was based on a racially and geographically diverse, population-based cohort of older adults. Racial/ethnic segregation (clustering) was measured by the Getis-ord (Gi*) statistic. We saw faster processing speed decline among Black individuals in segregated neighborhoods.

2023 Alzheimer's disease facts and figures

This article describes the public health impact of Alzheimer's disease, including prevalence and incidence, mortality and morbidity, use and costs of care, and the overall impact on family caregivers, the dementia workforce and society. The Special Report examines the patient journey from awareness of cognitive changes to potential treatment with drugs that change the underlying biology of Alzheimer's. An estimated 6.7 million Americans age 65 and older are living with Alzheimer's dementia today. This number could grow to 13.8 million by 2060 barring the development of medical breakthroughs to prevent, slow or cure AD. Official death certificates recorded 121,499 deaths from AD in 2019, and Alzheimer's disease was officially listed as the sixth-leading cause of death in the United States. In 2020 and 2021, when COVID-19 entered the ranks of the top ten causes of death, Alzheimer's was the seventh-leading cause of death. Alzheimer's remains the fifth-leading cause of death among Americans age 65 and older. Between 2000 and 2019, deaths from stroke, heart disease and HIV decreased, whereas reported deaths from AD increased more than 145%. This trajectory of deaths from AD was likely exacerbated by the COVID-19 pandemic in 2020 and 2021. More than 11 million family members and other unpaid caregivers provided an estimated 18 billion hours of care to people with Alzheimer's or other dementias in 2022. These figures reflect a decline in the number of caregivers compared with a decade earlier, as well as an increase in the amount of care provided by each remaining caregiver. Unpaid dementia caregiving was valued at $339.5 billion in 2022. Its costs, however, extend to family caregivers' increased risk for emotional distress and negative mental and physical health outcomes - costs that have been aggravated by COVID-19. Members of the paid health care workforce are involved in diagnosing, treating and caring for people with dementia. In recent years, however, a shortage of such workers has developed in the United States. This shortage - brought about, in part, by COVID-19 - has occurred at a time when more members of the dementia care workforce are needed. Therefore, programs will be needed to attract workers and better train health care teams. Average per-person Medicare payments for services to beneficiaries age 65 and older with AD or other dementias are almost three times as great as payments for beneficiaries without these conditions, and Medicaid payments are more than 22 times as great. Total payments in 2023 for health care, long-term care and hospice services for people age 65 and older with dementia are estimated to be $345 billion. The Special Report examines whether there will be sufficient numbers of physician specialists to provide Alzheimer's care and treatment now that two drugs are available that change the underlying biology of Alzheimer's disease.

Spatial Decomposition of Air Pollution Concentrations Highlights Historical Causes for Current Exposure Disparities in the United States

Racial-ethnic disparities in exposure to air pollution in the United States (US) are well documented. Studies on the causes of these disparities highlight unequal systems of power and longstanding systemic racism-for example, redlining, white flight, and racial covenants-which reinforced racial segregation and wealth gaps and which concentrated polluting land uses in communities of color. Our analysis is based on empirical estimates of ambient concentrations for two important pollutants (NO2 and PM2.5). We show that spatially decomposed concentrations can be used to infer and quantify types of root causes for local- to national-scale disparities. Urban-scale segregation is important yet reflects less than half of the overall national disparities. Other historical causes of national exposure disparities include those that led current populations of Black, Asian, and Hispanic Americans to live in larger cities; those outcomes are consistent with, for example, greater economic opportunity in large cities, land-takings from non-White farmers, and racism in homesteading and between-state migration. Our results suggest that contemporary national exposure disparities in the US reflect a broad set of historical local- to national-scale mechanisms-including racist laws and actions that include, but also extend beyond, urban-scale aspects-and offer a first attempt to quantify their relative importance.

Neighborhood segregation, socioeconomic status, and cognitive function among older Chinese immigrants

BACKGROUND

The fast-growing population of older Chinese immigrants and their segregated residences highlight the importance of understanding the role of neighborhood context in cognitive health. The segregation-cognition association is equivocal based on a limited number of studies among Hispanic and Asian Americans. To close the knowledge gap, this study examined the associations of neighborhood segregation and socioeconomic status (NSES) with cognitive functioning among older Chinese immigrants.

METHODS

Four waves of cognitive performance tests were conducted in the Population Study of Chinese Elderly in Chicago (2011-2019) and linked to the 2010 to 2014 American Community Survey estimates of neighborhood contexts. NSES was a summary z-score of six census variables of education, income/wealth, and occupation. Neighborhood segregation was measured by the Index of Concentrations at the Extremes (ICE), which simultaneously assesses Chinese and English language use within a given census tract. There were 170 census tracts in the present sample of 2044 participants. Latent growth curve models with adjusted cluster robust standard errors were estimated.

RESULTS

On average, cognitive functioning declined over time (B = -0.07, p < 0.001). After adjusting for individual-level predictors, living in high-NSES neighborhoods was associated with slower cognitive decline (B = 0.003, p = 0.04). ICE was not associated with cognitive functioning, but boosted the protective effect of high NSES on cognitive decline (B = 0.006, p = 0.05).

CONCLUSIONS

Neighborhood socioeconomic advantage was related to slower cognitive decline among older Chinese immigrants, especially among those living in neighborhoods with more English speakers or less segregation. This finding suggests complex associations between neighborhood context and cognitive health among Chinese immigrants.

Neighborhood socioeconomic status and segregation linked to cognitive decline

Introduction

Few longitudinal studies have examined the joint impact of neighborhood segregation and neighborhood socioeconomic status (NSES) in cognitive decline over time.

Methods

This study included non-Hispanic White (NHW, n = 209) and Black participants (n = 118) whose cognition was evaluated as part of an ongoing longitudinal study. Four distinct categories of segregation and NSES were evaluated for their association with cognitive outcomes (episodic memory, semantic memory, executive function, and spatial ability) using race-specific mixed-effects models.

Results

Compared to Black participants living in higher segregation-lower NSES areas, Black participants living in lower segregation-lower NSES areas or higher segregation-higher NSES areas experienced slower decline in episodic memory over time. Compared to NHW participants living in higher segregation-lower NSES areas, NHWs living in lower segregation-higher NSES areas experienced faster decline in spatial ability.

Discussion

Segregation and NSES are differentially associated with cognition depending on participant race. Further research is needed to replicate study results.

Epidemiology and Risk Factors for Dementia

In this article, the authors discuss primarily what is known about the epidemiology of all-cause dementia. Dementia is caused by a complex interplay of genetics, comorbidities, and lifestyle factors, and drug development has been challenging. However, evidence from large, prospective, observational studies has identified a variety of factors that may prevent or delay the onset of dementia. Several of these factors are modifiable and lend themselves to well to treatments currently available. The authors discuss the state of current evidence on dementia risk factors, the most promising avenues, and future directions for dementia prevention and management.

Associations between Homelessness and Alzheimer's Disease and Related Dementia: A Systematic Review

The homeless population in the United States is rapidly aging, with a parallel increase in Alzheimer's disease and related dementia (ADRD). During an evolving pandemic that jeopardizes employment and housing, assessing the relationship between ADRD and homelessness is critical since the latter is potentially intervenable. The objective of this study is to review the literature and determine whether there is an association between homelessness and dementia risk. A systematic review of existing studies was conducted through PubMED, SCOPUS, and EMBASE among others. Of the 228 results found, nine met inclusion criteria. Homeless studies mainly centered on veteran populations (n = 6/9). There is a complex relationship suggesting homelessness as a risk for and consequence of ADRD but also co-occurrence with psychiatric disorders, substance abuse, and traumatic injuries. Future studies should employ enumeration surveys with modular longitudinal tracking and measure social determinants of health, discrimination, chronic stress, and mood disorders.

The association of residential racial segregation with health among U.S. children: A nationwide longitudinal study

Residential racial segregation in the U.S. has been hypothesized as a fundamental cause driving health disparities across racial groups. Potential mechanisms include economic and social marginalization, subsequent constrained opportunities, and high stress. Yet evidence on residential segregation's association with health among Black and White children—particularly longitudinally—is sparse. This study aims to address this gap. We used data from the Panel Study of Income Dynamics (PSID), a national longitudinal study of U.S. households, analyzing information on 1,251 Black and 1,427 White children who participated in the Child Development Supplement (CDS) at least twice (survey waves 1997, 2002, 2007, 2014). We fit individual fixed-effects models to estimate the within-person association of neighborhood-level residential segregation, measured with local Getis-Ord G* statistics, with three outcomes (general health, weight status, and behavioral problems). We examined heterogeneous effects by age and sex. We also examined associations between health and childhood segregation trajectories, i.e., the pattern of children's residential segregation exposures from birth through when their health outcomes were measured, providing additional insight on dynamic experiences of segregation. In fixed effects models, among Black children, higher segregation was associated with worse self-rated health, especially for Black children who were older (aged 11–17 years). In trajectory models, among White children, moving out of highly segregated neighborhoods was associated with a lower probability of poor self-rated health, while moving into those neighborhoods or back and forth between neighborhood types were both associated with increased behavioral problems. Our findings highlight the importance of early-life residential segregation in shaping persistent racial health disparities, as well as the costs of segregation for all children living in highly segregated neighborhoods.

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We used a national longitudinal data set with rich health and residential history data observed throughout childhood.

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We employed fixed effects models and trajectory models.

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Living in segregated neighborhoods was associated with poorer self-rated health among Black and White children.

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Moving into segregated neighborhoods was associated with more behavioral problems among White children.

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Interventions are needed to reduce segregation and improve health-promoting resources for children in segregated communities.

The long shadow of residential racial segregation: Associations between childhood residential segregation trajectories and young adult health among Black US Americans

Residential racial segregation is a key manifestation of anti-Black structural racism, thought to be a fundamental cause of poor health; evidence has shown that it yields neighborhood disinvestment, institutional discrimination, and targeting of unhealthy products like tobacco and alcohol. Yet research on the long-term impacts of childhood exposure to residential racial segregation is limited. Here, we analyzed data on 1823 Black participants in the Panel Study of Income Dynamics, estimating associations between childhood segregation trajectories and young adult health. Black young adults who consistently lived in high-segregation neighborhoods throughout childhood experienced unhealthier smoking and drinking behaviors and higher odds of obesity compared to other trajectory groups, including children who moved into or out of high-segregation neighborhoods. Results were robust to controls for neighborhood and family poverty. Findings underscore that for Black children who grow up in segregated neighborhoods, the roots of structurally-determined health inequities are established early in life.

Methodological approaches for studying structural racism and its biopsychosocial impact on health

BACKGROUND

Structural racism is a powerful determinant of health that drives health disparities, morbidity, and mortality across racialized and minoritized groups.

PURPOSE

This article discusses approaches for measuring structural racism and its resultant network of negative biopsychosocial consequences for health and well-being.

METHODS

We draw on prevailing theoretical models and approaches to characterize both the nature of structural racism and integrated methods for assessing its consequences across mental and physical health.

DISCUSSION

This article will serve to guide researchers in health-related disciplines to accurately assess the biopsychosocial consequences of structural racism in key populations.

Elevated blood pressure is associated with advanced brain aging in mid-life: A 30-year follow-up of The CARDIA Study

BACKGROUND

High blood pressure (BP) is a risk factor for late-life brain health; however, the association of elevated BP with brain health in mid-life is unclear.

METHODS

We identified 661 participants from the Coronary Artery Risk Development in Young Adults Study (age 18-30 at baseline) with 30 years of follow-up and brain magnetic resonance imaging at year 30. Cumulative exposure of BP was estimated by time-weighted averages (TWA). Ideal cardiovascular health was defined as systolic BP < 120 mm Hg, diastolic BP < 80 mm Hg. Brain age was calculated using previously validated high dimensional machine learning pattern analyses.

RESULTS

Every 5 mmHg increment in TWA systolic BP was associated with approximately 1-year greater brain age (95% confidence interval [CI]: 0.50-1.36) Participants with TWA systolic or diastolic BP over the recommended guidelines for ideal cardiovascular health, had on average 3-year greater brain age (95% CI: 1.00-4.67; 95% CI: 1.45-5.13, respectively).

CONCLUSION

Elevated BP from early to mid adulthood, even below clinical cut-offs, is associated with advanced brain aging in mid-life.

School Racial Segregation and the Health of Black Children

OBJECTIVES

Few researchers have evaluated whether school racial segregation, a key manifestation of structural racism, affects child health, despite its potential impacts on school quality, social networks, and stress from discrimination. We investigated whether school racial segregation affects Black children's health and health behaviors.

METHODS

We estimated the association of school segregation with child health, leveraging a natural experiment in which school districts in recent years experienced increased school segregation. School segregation was operationalized as the Black-White dissimilarity index. We used ordinary least squares models as well as quasi-experimental instrumental variables analysis, which can reduce bias from unobserved confounders. Data from the Child Development Supplement of the Panel Study of Income Dynamics (1997-2014, n = 1248 Black children) were linked with district-level school segregation measures. Multivariable regressions were adjusted for individual-, neighborhood-, and district-level covariates. We also performed subgroup analyses by child sex and age.

RESULTS

In instrumental variables models, a one standard deviation increase in school segregation was associated with increased behavioral problems (2.53 points on a 27-point scale; 95% CI, 0.26 to 4.80), probability of having ever drunk alcohol (0.23; 95% CI, 0.049 to 0.42), and drinking at least monthly (0.20; 95% CI, 0.053 to 0.35). School segregation was more strongly associated with drinking behaviors among girls.

CONCLUSIONS

School segregation was associated with worse outcomes on several measures of well-being among Black children, which may contribute to health inequities across the life span. These results highlight the need to promote school racial integration and support Black youth attending segregated schools.

Racial Residential Segregation in Young Adulthood and Brain Integrity in Middle Age: Can We Learn From Small Samples?

Racial residential segregation is associated with multiple adverse health outcomes in Black individuals. Yet, the influence of structural racism and racial residential segregation on brain aging is less understood. In this study, we investigated the association between cumulative exposure to racial residential segregation over 25 years (1985-2010) in young adulthood, as measured by the Getis-Ord Gi* statistic, and year 25 measures of brain volume (cerebral, gray matter, white matter, and hippocampal volumes) in midlife. We studied 290 Black participants with available brain imaging data who were enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA) Study, a prospective cohort study. CARDIA investigators originally recruited 2,637 Black participants aged 18-30 years from 4 field centers across the United States. We conducted analyses using marginal structural models, incorporating inverse probability of treatment weighting and inverse probability of censoring weighting. We found that compared with low/medium segregation, greater cumulative exposure to a high level of racial residential segregation throughout young adulthood was associated with smaller brain volumes in general (e.g., for cerebral volume, β = -0.08, 95% confidence interval: -0.15, -0.02) and with a more pronounced reduction in hippocampal volume, though results were not statistically significant. Our findings suggest that exposure to segregated neighborhoods may be associated with worse brain aging.

2022 Alzheimer's disease facts and figures

This article describes the public health impact of Alzheimer's disease (AD), including incidence and prevalence, mortality and morbidity, use and costs of care, and the overall impact on family caregivers, the dementia workforce and society. The Special Report discusses consumers' and primary care physicians' perspectives on awareness, diagnosis and treatment of mild cognitive impairment (MCI), including MCI due to Alzheimer's disease. An estimated 6.5 million Americans age 65 and older are living with Alzheimer's dementia today. This number could grow to 13.8 million by 2060 barring the development of medical breakthroughs to prevent, slow or cure AD. Official death certificates recorded 121,499 deaths from AD in 2019, the latest year for which data are available. Alzheimer's disease was officially listed as the sixth-leading cause of death in the United States in 2019 and the seventh-leading cause of death in 2020 and 2021, when COVID-19 entered the ranks of the top ten causes of death. Alzheimer's remains the fifth-leading cause of death among Americans age 65 and older. Between 2000 and 2019, deaths from stroke, heart disease and HIV decreased, whereas reported deaths from AD increased more than 145%. More than 11 million family members and other unpaid caregivers provided an estimated 16 billion hours of care to people with Alzheimer's or other dementias in 2021. These figures reflect a decline in the number of caregivers compared with a decade earlier, as well as an increase in the amount of care provided by each remaining caregiver. Unpaid dementia caregiving was valued at $271.6 billion in 2021. Its costs, however, extend to family caregivers' increased risk for emotional distress and negative mental and physical health outcomes - costs that have been aggravated by COVID-19. Members of the dementia care workforce have also been affected by COVID-19. As essential care workers, some have opted to change jobs to protect their own health and the health of their families. However, this occurs at a time when more members of the dementia care workforce are needed. Average per-person Medicare payments for services to beneficiaries age 65 and older with AD or other dementias are almost three times as great as payments for beneficiaries without these conditions, and Medicaid payments are more than 22 times as great. Total payments in 2022 for health care, long-term care and hospice services for people age 65 and older with dementia are estimated to be $321 billion. A recent survey commissioned by the Alzheimer's Association revealed several barriers to consumers' understanding of MCI. The survey showed low awareness of MCI among Americans, a reluctance among Americans to see their doctor after noticing MCI symptoms, and persistent challenges for primary care physicians in diagnosing MCI. Survey results indicate the need to improve MCI awareness and diagnosis, especially in underserved communities, and to encourage greater participation in MCI-related clinical trials.

Alzheimer disease in African American individuals: increased incidence or not enough data?

Research on racial differences in Alzheimer disease (AD) dementia has increased in recent years. Older African American individuals bear a disproportionate burden of AD and cognitive impairment compared with non-Latino white individuals. Tremendous progress has been made over the past two decades in our understanding of the neurobiological substrates of AD. However, owing to well-documented challenges of study participant recruitment and a persistent lack of biological data in the African American population, knowledge of the drivers of these racial disparities has lagged behind. Therapeutic targets and effective interventions for AD are increasingly sought, but without a better understanding of the disease in African American individuals, any identified treatments and/or cures will evade this rapidly growing at-risk population. In this Perspective, I introduce three key obstacles to progress in understanding racial differences in AD: uncertainty about diagnostic criteria, disparate cross-sectional and longitudinal findings; and a dearth of neuropathological data. I also highlight evidence-informed strategies to move the field forward.

In this Perspective, Barnes introduces three key obstacles to progress in our understanding of racial differences in Alzheimer disease and highlights evidence-informed strategies that can move the field forward.

Relationship between Residential Segregation, Later-Life Cognition, and Incident Dementia across Race/Ethnicity

Systemic racism leads to racial/ethnic residential segregation, which can result in health inequities. We examined if the associations between residential segregation and later-life cognition and dementia differed based on segregation measure and by participant race/ethnicity. Tests of memory (n = 4616), language (n = 4333), visuospatial abilities (n = 4557), and incident dementia (n = 4556) were analyzed in older residents of Northern Manhattan, New York (mean age: 75.7 years). Segregation was measured at the block group-level using three indices: dissimilarity, isolation, and interaction. We fit multilevel linear or Cox proportional hazards models and included a race/ethnicity × segregation term to test for differential associations, adjusting for socioeconomic and health factors. Living in block groups with higher proportions of minoritized people was associated with -0.05 SD lower language scores. Living in block groups with higher potential contact between racial/ethnic groups was associated with 0.06-0.1 SD higher language scores. The findings were less pronounced for other cognitive domains and for incident dementia. Non-Hispanic Black adults were most likely to experience negative effects of neighborhood segregation on cognition (language and memory) and dementia. All indices partly capture downstream effects of structural racism (i.e., unequal distributions of wealth/resources) on cognition. Therefore, desegregation and equitable access to resources have the potential to improve later-life cognitive health.

Neighborhood racial/ethnic segregation and cognitive decline in older adults

Social determinants of health, including neighborhood factors, play a key role in the health of diverse older adults. However, few longitudinal studies have examined the role of neighborhood racial/ethnic segregation on cognitive decline in diverse samples. We examined older non-Hispanic White (NHW), Black, and Latino participants evaluated at an Alzheimer's Disease Research Center. Neighborhood racial/ethnic segregation was measured using the Getis-Ord Gi* statistic, a spatial measure of clustering that was created for Latino and Black clustering separately. Cognitive outcomes included episodic memory, semantic memory, and executive function. We used mixed effects multivariable regression models to evaluate associations between segregation and cognitive function and decline. We had 452 individuals: 46% NHW, 26% Black, and 21% Latino in 309 census tracts with an average of 5.2 years of follow-up data (range 0.6-15.0). In analyses that adjusted for a variety of covariates (including neighborhood SES), individuals in neighborhoods with a higher clustering of Latino residents (higher Gi* statistic) had slower declines over time on semantic memory and those in neighborhoods with a higher clustering of Black residents had slower declines over time on episodic memory. In race/ethnicity-stratified adjusted analyses: for Black participants, the association between clustering and cognition was present for episodic memory and executive function, showing lower baseline scores in highly clustered Black and Latino neighborhoods, respectively. There was no association with cognitive change. Among Latino participants, highly clustered Latino neighborhoods were associated with lower baseline scores in semantic memory, but slower declines in episodic memory; Latinos living in neighborhoods with a greater clustering of Black residents also had slower declines in episodic memory. Among NHWs, residing in neighborhoods with a higher clustering of Latino residents was associated with slower declines over time on semantic memory. Segregated neighborhoods may be differentially associated with cognitive outcomes depending on individual race/ethnicity.

Racial/Ethnic Disparities in Alzheimer's Disease Risk: Role of Exposure to Ambient Fine Particles

BACKGROUND

Whether racial/ethnic disparities in Alzheimer's disease (AD) risk may be explained by ambient fine particles (PM2.5) has not been studied.

METHOD

We conducted a prospective, population-based study on a cohort of Black (n = 481) and White (n = 6 004) older women (aged 65-79) without dementia at enrollment (1995-1998). Cox models accounting for competing risk were used to estimate the hazard ratio (HR) for racial/ethnic disparities in AD (1996-2010) defined by Diagnostic and Statistical Manual of Mental Disorders, 4th edition and the association with time-varying annual average PM2.5 (1999-2010) estimated by spatiotemporal model.

RESULTS

Over an average follow-up of 8.3 (±3.5) years with 158 incident cases (21 in Black women), the racial disparities in AD risk (range of adjusted HRBlack women = 1.85-2.41) observed in various models could not be explained by geographic region, age, socioeconomic characteristics, lifestyle factors, cardiovascular risk factors, and hormone therapy assignment. Estimated PM2.5 exposure was higher in Black (14.38 ± 2.21 µg/m3) than in White (12.55 ± 2.76 µg/m3) women, and further adjustment for the association between PM2.5 and AD (adjusted HRPM2.5 = 1.18-1.28) slightly reduced the racial disparities by 2%-6% (HRBlack women = 1.81-2.26). The observed association between PM2.5 and AD risk was ~2 times greater in Black (HRPM2.5 = 2.10-2.60) than in White (HRPM2.5 = 1.07-1.15) women (range of interaction ps: <.01-.01). We found similar results after further adjusting for social engagement (social strain, social support, social activity, living alone), stressful life events, Women's Health Initiative's clinic sites, and neighborhood socioeconomic characteristics.

CONCLUSIONS

PM2.5 may contribute to racial/ethnic disparities in AD risk and its associated increase in AD risk was stronger among Black women.

Developing methods to detect and diagnose chronic traumatic encephalopathy during life: rationale, design, and methodology for the DIAGNOSE CTE Research Project

BACKGROUND

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease that has been neuropathologically diagnosed in brain donors exposed to repetitive head impacts, including boxers and American football, soccer, ice hockey, and rugby players. CTE cannot yet be diagnosed during life. In December 2015, the National Institute of Neurological Disorders and Stroke awarded a seven-year grant (U01NS093334) to fund the "Diagnostics, Imaging, and Genetics Network for the Objective Study and Evaluation of Chronic Traumatic Encephalopathy (DIAGNOSE CTE) Research Project." The objectives of this multicenter project are to: develop in vivo fluid and neuroimaging biomarkers for CTE; characterize its clinical presentation; refine and validate clinical research diagnostic criteria (i.e., traumatic encephalopathy syndrome [TES]); examine repetitive head impact exposure, genetic, and other risk factors; and provide shared resources of anonymized data and biological samples to the research community. In this paper, we provide a detailed overview of the rationale, design, and methods for the DIAGNOSE CTE Research Project.

METHODS

The targeted sample and sample size was 240 male participants, ages 45-74, including 120 former professional football players, 60 former collegiate football players, and 60 asymptomatic participants without a history of head trauma or participation in organized contact sports. Participants were evaluated at one of four U.S. sites and underwent the following baseline procedures: neurological and neuropsychological examinations; tau and amyloid positron emission tomography; magnetic resonance imaging and spectroscopy; lumbar puncture; blood and saliva collection; and standardized self-report measures of neuropsychiatric, cognitive, and daily functioning. Study partners completed similar informant-report measures. Follow-up evaluations were intended to be in-person and at 3 years post-baseline. Multidisciplinary diagnostic consensus conferences are held, and the reliability and validity of TES diagnostic criteria are examined.

RESULTS

Participant enrollment and all baseline evaluations were completed in February 2020. Three-year follow-up evaluations began in October 2019. However, in-person evaluation ceased with the COVID-19 pandemic, and resumed as remote, 4-year follow-up evaluations (including telephone-, online-, and videoconference-based cognitive, neuropsychiatric, and neurologic examinations, as well as in-home blood draw) in February 2021.

CONCLUSIONS

Findings from the DIAGNOSE CTE Research Project should facilitate detection and diagnosis of CTE during life, and thereby accelerate research on risk factors, mechanisms, epidemiology, treatment, and prevention of CTE.

TRIAL REGISTRATION

NCT02798185.

Human Brain Resilience: A Call to Action

At present, resilience refers to a highly heterogeneous concept with ill-defined determinants, mechanisms, and outcomes. This call for action argues for the need to define resilience as a person-centered multidimensional metric, informed by a dynamic lifespan perspective and combining observational and interventional experimental studies to identify specific neural markers and correlated behavioral measures. The coronavirus disease 2019 (COVID-19) pandemic highlights the urgent need of such an effort with the ultimate goal of defining a new vital sign, an individual index of resilience, as a life-long metric with the capacity to predict an individual's risk for disability in the face of a stressor, insult, injury, or disease. ANN NEUROL 2021.

Racial segregation and cognitive function among older adults in the United States: Findings from the REasons for Geographic and Racial Differences in Stroke (REGARDS) study

OBJECTIVES

Residential segregation is one of the fundamental features of health disparities in the United States. Yet little research has examined how living in segregated metropolitan areas is related to cognitive function and cognitive decline with age. We examined the association between segregation at the Metropolitan Statistical Area (MSA) level and trajectories of age-related cognitive function.

METHOD

Using data from Black and White older adults in the REasons for Geographic and Racial Differences in Stroke (REGARDS) study (n=18,913), we employed linear growth curve models to examine how living in racially segregated MSAs at baseline, measured by the degree of Non-Hispanic Black [NHB] isolation and NHB dissimilarity, was associated with trajectories of age-related cognitive function and how the associations varied by race and education.

RESULTS

Living in MSAs with greater levels of isolation was associated with lower cognitive function (b=-0.093, p<0.05) but was not associated with rates of change in cognitive decline with age. No effects of living in isolated MSAs were found for those with at least a high school education, but older adults with less than a high school education had lower cognitive function in MSAs with greater isolation (b=-0.274, p<0.05). The degree of dissimilarity was not associated with cognitive function. The association between segregation and cognitive function did not vary by race.

DISCUSSION

Metropolitan segregation was associated with lower cognitive function among older adults, especially for those with lower education living in racially isolated MSAs. This suggests complex associations between individual socioeconomic status, place, and cognitive health.

Methods to Address Self-Selection and Reverse Causation in Studies of Neighborhood Environments and Brain Health

Preliminary evidence suggests that neighborhood environments, such as socioeconomic disadvantage, pedestrian and physical activity infrastructure, and availability of neighborhood destinations (e.g., parks), may be associated with late-life cognitive functioning and risk of Alzheimer’s disease and related disorders (ADRD). The supposition is that these neighborhood characteristics are associated with factors such as mental health, environmental exposures, health behaviors, and social determinants of health that in turn promote or diminish cognitive reserve and resilience in later life. However, observed associations may be biased by self-selection or reverse causation, such as when individuals with better cognition move to denser neighborhoods because they prefer many destinations within walking distance of home, or when individuals with deteriorating health choose residences offering health services in neighborhoods in rural or suburban areas (e.g., assisted living). Research on neighborhood environments and ADRD has typically focused on late-life brain health outcomes, which makes it difficult to disentangle true associations from associations that result from reverse causality. In this paper, we review study designs and methods to help reduce bias due to reverse causality and self-selection, while drawing attention to the unique aspects of these approaches when conducting research on neighborhoods and brain aging.

Educational Benefits and Cognitive Health Life Expectancies: Racial/Ethnic, Nativity, and Gender Disparities

BACKGROUND AND OBJECTIVES

To examine racial/ethnic, nativity, and gender differences in the benefits of educational attainment on cognitive health life expectancies among older adults in the United States.

RESEARCH DESIGN AND METHODS

We used data from the Health and Retirement Study (1998-2014) to estimate Sullivan-based life tables of cognitively healthy, cognitively impaired/no dementia, and dementia life expectancies by gender for older White, Black, U.S.-born Hispanic, and foreign-born Hispanic adults with less than high school, high school, and some college or more.

RESULTS

White respondents lived a greater percentage of their remaining lives cognitively healthy than their minority Black or Hispanic counterparts, regardless of level of education. Among respondents with some college or more, versus less than high school, Black and U.S.-born Hispanic women exhibited the greatest increase (both 37 percentage points higher) in the proportion of total life expectancy spent cognitively healthy; whereas White women had the smallest increase (17 percentage points higher). For men, the difference between respondents with some college or more, versus less than high school, was greatest for Black men (35 percentage points higher) and was lowest for U.S.-born Hispanic men (21 percentage points higher).

DISCUSSION AND IMPLICATIONS

Our results provide evidence that the benefits of education on cognitive health life expectancies are largest for Black men and women and U.S.-born Hispanic women. The combination of extended longevity and rising prevalence of Alzheimer's disease points to the need for understanding why certain individuals spend an extended period of their lives with poor cognitive health.

2021 Alzheimer's disease facts and figures

This article describes the public health impact of Alzheimer's disease (AD), including incidence and prevalence, mortality and morbidity, use and costs of care, and the overall impact on caregivers and society. The Special Report discusses the challenges of providing equitable health care for people with dementia in the United States. An estimated 6.2 million Americans age 65 and older are living with Alzheimer's dementia today. This number could grow to 13.8 million by 2060 barring the development of medical breakthroughs to prevent, slow or cure AD. Official death certificates recorded 121,499 deaths from AD in 2019, the latest year for which data are available, making Alzheimer's the sixth-leading cause of death in the United States and the fifth-leading cause of death among Americans age 65 and older. Between 2000 and 2019, deaths from stroke, heart disease and HIV decreased, whereas reported deaths from AD increased more than 145%. This trajectory of deaths from AD was likely exacerbated in 2020 by the COVID-19 pandemic. More than 11 million family members and other unpaid caregivers provided an estimated 15.3 billion hours of care to people with Alzheimer's or other dementias in 2020. These figures reflect a decline in the number of caregivers compared with a decade earlier, as well as an increase in the amount of care provided by each remaining caregiver. Unpaid dementia caregiving was valued at $256.7 billion in 2020. Its costs, however, extend to family caregivers' increased risk for emotional distress and negative mental and physical health outcomes - costs that have been aggravated by COVID-19. Average per-person Medicare payments for services to beneficiaries age 65 and older with AD or other dementias are more than three times as great as payments for beneficiaries without these conditions, and Medicaid payments are more than 23 times as great. Total payments in 2021 for health care, long-term care and hospice services for people age 65 and older with dementia are estimated to be $355 billion. Despite years of efforts to make health care more equitable in the United States, racial and ethnic disparities remain - both in terms of health disparities, which involve differences in the burden of illness, and health care disparities, which involve differences in the ability to use health care services. Blacks, Hispanics, Asian Americans and Native Americans continue to have a higher burden of illness and lower access to health care compared with Whites. Such disparities, which have become more apparent during COVID-19, extend to dementia care. Surveys commissioned by the Alzheimer's Association recently shed new light on the role of discrimination in dementia care, the varying levels of trust between racial and ethnic groups in medical research, and the differences between groups in their levels of concern about and awareness of Alzheimer's disease. These findings emphasize the need to increase racial and ethnic diversity in both the dementia care workforce and in Alzheimer's clinical trials.