Stressors in Midlife and Risk of Dementia: The Role of Race and Education

Is the Health of Older Americans With a GED Equivalent to Their Peers With a High School Diploma?

The aim of this study was to identify differences in the prevalence and odds of cognitive impairment, hearing impairment, vision impairment, limitations in activities of daily living (ADLs), and ambulation limitations among three groups of older American adults: high school dropouts, General Educational Development (GED) recipients, and high school graduates. This study used secondary analysis of the nationally representative 2017 American Community Survey. The sample included 20,489 GED recipients, 154,892 high school graduates, and 49,912 high school dropouts. Our findings indicate that there is a gradient in health outcomes among older Americans, with the highest prevalence and odds of cognitive impairment, hearing impairment, vision impairment, ADL limitations, and ambulation limitations among high school dropouts, followed by GED recipients, and the lowest among high school graduates. Although GED recipients have better health outcomes than high school dropouts, there is still a significant disparity in health status between GED recipients and high school graduates.

Empirically derived psychosocial-behavioral phenotypes in Black/African American and Hispanic/Latino older adults enrolled in HABS-HD: Associations with AD biomarkers and cognitive outcomes

INTRODUCTION

Identification of psychosocial-behavioral phenotypes to understand within-group heterogeneity in risk and resiliency to Alzheimer's disease (AD) within Black/African American and Hispanic/Latino older adults is essential for the implementation of precision health approaches.

METHODS

A cluster analysis was performed on baseline measures of socioeconomic resources (annual income, social support, occupational complexity) and psychiatric distress (chronic stress, depression, anxiety) for 1220 racially/ethnically minoritized adults enrolled in the Health and Aging Brain Study-Health Disparities (HABS-HD). Analyses of covariance adjusting for sociodemographic factors examined phenotype differences in cognition and plasma AD biomarkers.

RESULTS

The cluster analysis identified (1) Low Resource/High Distress (n = 256); (2) High Resource/Low Distress (n = 485); and (3) Low Resource/Low Distress (n = 479) phenotypes. The Low Resource/High Distress phenotype displayed poorer cognition and higher plasma neurofilament light chain; differences between the High Resource/Low Distress and Low Resource/Low Distress phenotypes were minimal.

DISCUSSION

The identification of psychosocial-behavioral phenotypes within racially/ethnically minoritized older adults is crucial to the development of targeted AD prevention and intervention efforts.

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.

Is Stress an Overlooked Risk Factor for Dementia? A Systematic Review from a Lifespan Developmental Perspective

Stress exposure and stress reactivity may be potent factors associated with increased risk of dementia. The 2017 Lancet Commission on Dementia and its 2020 update reviewed modifiable risk factors associated with dementia, but stress was not addressed directly. The present study provides a focused review of the association between stress and dementia across the lifespan, with measures of stress including stress exposure, psychological stress, posttraumatic stress disorder (PTSD), and biological markers of stress. Published research articles were identified in the American Psychological Association PsycINFO database (1887-2021), Web of Science database, and Google Scholar. A total of 53 samples from 40 studies published from 1985 to 2020 met inclusion criteria. Results suggest that stressful life events that occur earlier in the lifespan, such as loss of a parent, psychological stress experienced in midlife, and extreme stress responses, i.e., PTSD, correlate with higher risk of dementia. Although results generally are mixed, a consistent theme is that stress experienced earlier in the lifespan and chronic stress portend the greatest risk of dementia. Reducing stress exposure and improving stress management when stress exposure cannot be changed are thus relevant strategies in dementia risk reduction.

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.

Health Disparities in Dementia

PURPOSE OF REVIEW

Causes of health disparities in Alzheimer disease and related dementias (ADRD) in the United States are multifactorial. This article contextualizes health disparities as they relate to the neurodegenerative processes of ADRD.

RECENT FINDINGS

Older adults' life expectancy has increased such that a 65-year-old is expected to live 19 or more years and an 85-year-old can expect to live, on average, 6 to 7 years longer. Individuals of certain ethnoracial groups (Black, Hispanic/Latino, American Indian/Alaska Native, and Native Hawaiian/Pacific Islander) may be at a higher risk of incident ADRD compared to non-Hispanic/Latino White people. These differences in a higher risk of ADRD across ethnoracial groups persist despite no statistically significant differences in the rate of cognitive decline over time. The intersectionality of social determinants of health, experiences with discrimination and oppression, and access to care are related to the issue of justice and the risk for and expression of ADRD. The theoretical frameworks of various health disparities provide organized approaches to tracking the progression of health disparities for diverse patients.

SUMMARY

ADRD health disparities are complex. Neurologists and their care teams must consider the main reasons for clinical ADRD evaluations of members of ethnoracial groups and the factors that may impact patient adherence and compliance with diagnostic and management recommendations.

A Multimodal Risk Network Predicts Executive Function Trajectories in Non-demented Aging

Background: Multiple modalities of Alzheimer's disease (AD) risk factors may operate through interacting networks to predict differential cognitive trajectories in asymptomatic aging. We test such a network in a series of three analytic steps. First, we test independent associations between three risk scores (functional-health, lifestyle-reserve, and a combined multimodal risk score) and cognitive [executive function (EF)] trajectories. Second, we test whether all three associations are moderated by the most penetrant AD genetic risk [Apolipoprotein E (APOE) ε4+ allele]. Third, we test whether a non-APOE AD genetic risk score further moderates these APOE × multimodal risk score associations. Methods: We assembled a longitudinal data set (spanning a 40-year band of aging, 53-95 years) with non-demented older adults (baseline n = 602; Mage = 70.63(8.70) years; 66% female) from the Victoria Longitudinal Study (VLS). The measures included for each modifiable risk score were: (1) functional-health [pulse pressure (PP), grip strength, and body mass index], (2) lifestyle-reserve (physical, social, cognitive-integrative, cognitive-novel activities, and education), and (3) the combination of functional-health and lifestyle-reserve risk scores. Two AD genetic risk markers included (1) APOE and (2) a combined AD-genetic risk score (AD-GRS) comprised of three single nucleotide polymorphisms (SNPs; Clusterin[rs11136000], Complement receptor 1[rs6656401], Phosphatidylinositol binding clathrin assembly protein[rs3851179]). The analytics included confirmatory factor analysis (CFA), longitudinal invariance testing, and latent growth curve modeling. Structural path analyses were deployed to test and compare prediction models for EF performance and change. Results: First, separate analyses showed that higher functional-health risk scores, lifestyle-reserve risk scores, and the combined score, predicted poorer EF performance and steeper decline. Second, APOE and AD-GRS moderated the association between functional-health risk score and the combined risk score, on EF performance and change. Specifically, only older adults in the APOEε4- group showed steeper EF decline with high risk scores on both functional-health and combined risk score. Both associations were further magnified for adults with high AD-GRS. Conclusion: The present multimodal AD risk network approach incorporated both modifiable and genetic risk scores to predict EF trajectories. The results add an additional degree of precision to risk profile calculations for asymptomatic aging populations.

Associations between education and dementia in the Caribbean and the United States: An international comparison

INTRODUCTION

Despite high dementia prevalence in Hispanic populations globally, especially Caribbean Hispanics, no study has comparatively examined the association between education and dementia among Hispanics living in the Caribbean Islands and older adults in the United States.

METHODS

We used data on 6107 respondents aged 65 and older in the baseline wave of the population-based and harmonized 10/66 survey from Cuba, the Dominican Republic, and Puerto Rico, collected between 2003 and 2008, and 11,032 respondents aged 65 and older from the U.S.-based Health and Retirement Study data in 2014, a total of 17,139 individuals. We estimated multivariable logistic regression models examining the association between education and dementia, adjusted for age, income, assets, and occupation. The models were estimated separately for the Caribbean population (pooled and by setting) and the U.S. population by race/ethnicity (Hispanic, Black, and White), followed by pooled models across all populations.

RESULTS

In the Caribbean population, the relative risk of dementia among low versus high educated adults was 1.45 for women (95% confidence interval [CI] 1.17, 1.74) and 1.92 (95% CI 1.35, 2.49) for men, smaller compared to those in the United States, especially among non-Hispanic Whites (women: 2.78, 95% CI 1.94, 3.61; men: 5.98, 95% CI 4.02, 7.95).

DISCUSSION

The differential associations between education and dementia across the Caribbean and US settings may be explained by greater disparities in social conditions in the United States compared to the Caribbean, such as access to health care, healthy behaviors, and social stressors, which serve as potentially important mediators.

Association of Stress with Risk of Dementia and Mild Cognitive Impairment: A Systematic Review and Meta-Analysis

BACKGROUND

Although many studies have investigated the association between stress and risk of dementia, findings are inconsistent due to the variation in the measures used to assess stress.

OBJECTIVE

We conducted a systematic review and meta-analysis to investigate the association between psychological stress (including neuroticism, stressful life events, and perceived stress) and the risk of incident dementia and mild cognitive impairment in adults.

METHODS

PsycINFO, Embase, and MEDLINE were searched to October 2020 for eligible observational, prospective studies. Of the 1,607 studies screened, 26 (24 unique cohorts) were included in the qualitative analysis and 16 (15 unique cohorts) were included in the quantitative analysis.

RESULTS

Across studies, higher perceived stress was significantly associated with an increased risk of mild cognitive impairment (Cases/Total N = 207/860: hazard ratio [HR] = 1.19, 95% confidence interval [CI] = 1.03-1.38) and all-cause dementia (Cases/Total N = 203/1,882: HR = 1.44, 95% CI = 1.07-1.95). Exposure to two or more stressful life events (versus none) was significantly associated with an increased risk of all-cause dementia (Cases/Total N = 3,354/11,597: HR = 1.72, 95% CI = 1.14-2.60), while one or more stressful life events was not. Higher neuroticism was significantly associated with an increased risk of Alzheimer's disease dementia (Cases/Total N = 497/4,771: HR = 1.07, 95% CI = 1.01-1.12), but not all-cause dementia.

CONCLUSION

This review suggests that psychological stress in adulthood is associated with an increased risk of dementia. Further research is needed to clarify the mechanisms underlying these associations.

Alzheimer's Disease and Alzheimer's Disease-Related Dementias in Older African American and White Veterans

BACKGROUND

Racial disparity in the epidemiology of Alzheimer's disease and Alzheimer's disease-related dementias (AD/ADRD) has been reported. However, less is known about this disparity among Veterans.

OBJECTIVE

To estimate the racial disparity in AD/ADRD among the Veterans.

METHODS

Of the 5,413,418 Veterans≥65 years receiving care at the Veterans Health Administration (1999-2016), 4,045,269 were free of prevalent AD/ADRD, schizophrenia, or bipolar disorder at baseline. Of these, 432,469 were African American. Race was self-identified and incident AD/ADRD during 20 (median 6.7) years of follow-up was ascertained using International Classification of Diseases codes.

RESULTS

Patients had a mean age of 70.4 (±6.6) years and 97.8% were men. Age-sex-adjusted incidence of AD/ADRD per 1,000 person-year was 19.3 and 10.8 for African American and white Veterans, respectively (age-sex-adjusted hazard ratio associated with African American race, 1.77; 95% confidence interval, 1.75-1.79; p < 0.0001). This association remained essentially unchanged after multivariable adjustment (hazard ratio, 1.67; 95% confidence interval, 1.65-1.69; p < 0.0001). Among the key baseline characteristics that were significant predictors of AD/ADRD in both races, stroke was a significantly stronger predictor among African Americans, and Hispanic ethnicity and depression among whites (p-value for all interaction,<0.0001).

CONCLUSION

The findings of a higher incidence of AD/ADRD among African American Veterans is consistent with the findings in the general population reported in the literature, although the overall incidence appears to be lower than that in the general population. Future studies need to examine this disparity in incidence as well as the between-race heterogeneity in AD/ADRD risk.

African Americans Have Differences in CSF Soluble TREM2 and Associated Genetic Variants

Objective

To evaluate for racial differences in triggering receptor expressed on myeloid cells 2 (TREM2), a key immune mediator in Alzheimer disease, the levels of CSF soluble TREM2 (sTREM2), and the frequency of associated genetic variants were compared in groups of individuals who self-reported their race as African American (AA) or non-Hispanic White (NHW).

Methods

Community-dwelling older research participants underwent measurement of CSF sTREM2 concentrations and genetic analyses.

Results

The primary cohort included 91 AAs and 868 NHWs. CSF sTREM2 levels were lower in the AA compared with the NHW group (1,336 ± 470 vs 1,856 ± 624 pg/mL, p < 0.0001). AAs were more likely to carry TREM2 coding variants (15% vs 3%, p < 0.0001), which were associated with lower CSF sTREM2. AAs were less likely to carry the rs1582763 minor allele (8% vs 37%, p < 0.0001), located near MS4A4A, which was associated with higher CSF sTREM2. These findings were replicated in an independent cohort of 23 AAs and 917 NHWs: CSF sTREM2 levels were lower in the AA group (p = 0.03), AAs were more likely to carry coding TREM2 variants (22% vs 4%, p = 0.002), and AAs were less likely to carry the rs1582763 minor allele (16% vs 37%, p = 0.003).

Conclusions

On average, AAs had lower CSF sTREM2 levels compared with NHWs, potentially because AAs are more likely to carry genetic variants associated with lower CSF sTREM2 levels. Importantly, CSF sTREM2 reflects TREM2-mediated microglial activity, a critical step in the immune response to amyloid plaques. These findings suggest that race may be associated with risk for genetic variants that influence Alzheimer disease–related inflammation.

Race, genetic admixture and cognitive performance in the Cuban population

BACKGROUND

Population aging will lead to a dramatic increase in dementia prevalence, which will disproportionally affect racial minorities. The presence of racial differences in dementia prevalence has been widely reported in United States, but there are no relevant studies on this topic in low-middle income countries (LMIC).

METHODS

In a cross-sectional survey, 2,944 older Cubans were recruited at a community-based level aimed to identify the effects of self-identified race and genetic admixture on cognitive performance. Dementia diagnosis was established using 10/66 Dementia and DSM-IV criteria. APOE-ε4 genotype was determined in 2,511 (85%) and genetic admixture was completed for all dementia cases and in a randomly selected sample of cognitive healthy participants (218 dementia cases and 367 participants without dementia).

RESULTS

The overall prevalence of dementia was 8.7%, without large or statistically significant differences on dementia prevalence (p=0.12) by self-identified race. Mean cognitive scores were similar across racial groups (p=0.46). After controlling for age, sex and education, greater proportion of African ancestry was not associated with cognitive performance (p=0.17).

CONCLUSIONS

We found no evidence of an independent effect of self-identified race and/or population ancestry on dementia prevalence or cognitive performance. This suggests that observed differences in dementia prevalence among diverse populations may be driven primarily by social determinants of health.

Design and overview of the Origins of Alzheimer's Disease Across the Life course (ORACLE) study

Brain development and deterioration across the lifespan are integral to the etiology of late-life neurodegenerative disease. Factors that influence the health of the adult brain remain to be elucidated and include risk factors, protective factors, and factors related to cognitive and brain reserve. To address this knowledge gap we designed a life-course study on brain health, which received funding through the EU ERC Programme under the name Origins of Alzheimer’s Disease Across the Life course (ORACLE) Study. The ORACLE Study is embedded within Generation R, a prospective population-based cohort study of children and their parents, and links this with the Rotterdam Study, a population-based study in middle-aged and elderly persons. The studies are based in Rotterdam, the Netherlands. Generation R focuses on child health from fetal life until adolescence with repeated in-person examinations, but has also included data collection on the children’s parents. The ORACLE Study aims to extend the parental data collection in nearly 2000 parents with extensive measures on brain health, including neuroimaging, cognitive testing and motor testing. Additionally, questionnaires on migraine, depressive symptoms, sleep, and neurological family history were completed. These data allow for the investigation of longitudinal influences on adult brain health as well as intergenerational designs involving children and parents. As a secondary focus, the sampling is enriched by mothers (n = 356) that suffered from hypertensive disorders during pregnancy in order to study brain health in this high-risk population. This article provides an overview of the rationale and the design of the ORACLE Study.

Women's Work-Family Histories and Cognitive Performance in Later Life

Long-term exposures to the stress and stimulation of different work, parenting, and partnership combinations might influence later life cognition. We investigated the relationship between women's work-family life histories and cognitive functioning in later life. Analyses were based on data from women born between 1930 and 1957 in 14 European countries, from the Survey of Health, Ageing and Retirement in Europe (2004-2009) (n = 11,908). Multichannel sequence analysis identified 5 distinct work-family typologies based on women's work, partnership, and childrearing statuses between ages 12 and 50 years. Multilevel regressions were used to test the association between work-family histories and later-life cognition. Partnered mothers who mainly worked part-time had the best cognitive function in later life, scoring approximately 0.63 (95% confidence interval (CI): 0.18, 1.07) points higher than mothers who worked full-time on a 19-point scale. Partnered mothers who were mainly unpaid caregivers or who did other unpaid activities had cognitive scores that were 1.19 (95% CI: 0.49, 1.89) and 0.93 (95% CI: 0.20, 1.66) points lower than full-time working mothers. The findings are robust to adjustment for childhood advantage and educational credentials. This study provides new evidence that long-term exposures to certain social role combinations after childhood and schooling are linked to later-life cognition.

Physiological and pathological functions of beta-amyloid in the brain and alzheimer's disease: A review

Alzheimer's disease is a major health problem all over the world. The role of beta-amyloid (Aβ) is at the center of investigations trying to discover the disease pathogenesis and to develop drugs for treatment or prevention on Alzheimer's disease. This review summarizes both physiological and pathological functions of Aβ and factors that may participate in the disease development. Known genetic factors are trisomy of chromosome 21, mutations of presenilin 1 and 2, and apolipoprotein E4. Lifetime stresses that increase the risk of development of Alzheimer's disease are described. Another important factor is the level of education, especially of linguistic ability. Lifestyle factors include mental and physical exercise, head injury, social contacts, and diet. All these factors might potentiate the effect of aging on the brain to increase the risk of development of pathological changes. The review summarizes pathological features of Alzheimer brain, Aβ plaques, neurofibrillary tangles composed of hyperphosphorylated tau, and brain atrophy. Consequences of Alzheimer's disease that are reviewed include cognitive deficit, loss of function, and neuropsychiatric symptoms. Because there is no effective treatment, many persons with Alzheimer's disease survive to severe and terminal stages which they may fear. Alzheimer's disease at this stage should be considered a terminal disease for which palliative care is indicated. Importance of advance directives, promoting previous wishes of the person who was developing dementia and who subsequently lost decision-making capacity, and limitations of these directives are discussed. Information in this review is based on author's knowledge and clinical experience that were updated by searches of PubMed.

An Agenda for Addressing Multimorbidity and Racial and Ethnic Disparities in Alzheimer's Disease and Related Dementia

Advancements in Alzheimer's disease and related dementias (ADRD) research on the U.S. population acknowledge the importance of the high burden of ADRD on segments of the population and yet-to-be characterized risks attributable to the burden of multiple chronic diseases (multimorbidity). These realizations suggest successful strategies in caring for people with ADRD and their caregivers will rely not only on clinical treatments but also on more refined and comprehensive models of ADRD that take its broad effects on the whole-person and the whole of society into consideration. To this end, it is critical to characterize and address the relationship between ADRD and multimorbidity combinations that complicate care and lead to poor outcomes, particularly with regard to racial and ethnic disparities in the occurrence, course, and effects of ADRD. Several research and policy recommendations are presented to address the intersection of ADRD, multimorbidity, and underrepresented populations most at risk for adverse outcomes.

Polymorphisms of Proinflammatory Cytokines in Relation to APOE Epsilon 4 and Risk of Alzheimer's Disease in the Lithuanian Population

Background and objective: Neuroinflammation is one of the pathological pathways of Alzheimer's disease (AD), mediating the progression of neurodegeneration. Polymorphisms of proinflammatory cytokines have been linked to increased AD risk. Identification of certain combinations of polymorphisms could help predict disease in its preclinical stage. The aim of the study was to evaluate differences in the prevalence of TNFα -850T (rs1799724), IL1A -889T (rs1800587), and IL6 -174C (rs1800795, Intron type) polymorphisms between AD patients and healthy controls (HC) and determine the impact of these SNPs in combination with the APOEε4 allele on AD risk. Materials and Methods: The study population is comprised of 107 patients with sporadic AD (AD group) and age- and gender-matched 110 persons without impaired cognitive functions (control group). TNFα -850C > T polymorphism was revealed by a PCR and restriction fragment length polymorphism (RFLP) method. Real time PCR was used for IL1A and IL6 SNP genotyping. APOEε genotyping was done via hybridization method. Results: The frequencies of TNFα -850T, IL1A -889T, IL6 -174C allele and genotype did not differ between the AD and HC groups (p > 0.05). IL6 -174C was not in HWE, and it was not analysed further. APOEε4 allele (p = 0.001) and 3/4 and 4/4 genotypes (p = 0.005) were more prevalent in AD patients. APOEε4 carriage increased the risk of AD (OR 2.65, p = 0.001), while TNFα -850T and IL1A -889T polymorphisms were not found as significant independent risk factors for AD. The presence of at least one IL1A -889T allele in combination with APOEε4+ was associated with a lower risk of AD (OR 2.24, p = 0.047) than the carriage of APOEε4+ alone (OR 2.70, p = 0.015). Conclusions: No significant differences of TNFα -850, IL1A -889, and IL6 -174 polymorphisms frequencies were found between AD and control groups. In APOEε4 carriers IL1A -889T polymorphism was found to reduce the AD risk determined by APOEε4 alone.