Life-Course Individual and Neighborhood Socioeconomic Status and Risk of Dementia in the Atherosclerosis Risk in Communities Neurocognitive Study

Gaps in the usage and reporting of multiple imputation for incomplete data: findings from a scoping review of observational studies addressing causal questions

BACKGROUND

Missing data are common in observational studies and often occur in several of the variables required when estimating a causal effect, i.e. the exposure, outcome and/or variables used to control for confounding. Analyses involving multiple incomplete variables are not as straightforward as analyses with a single incomplete variable. For example, in the context of multivariable missingness, the standard missing data assumptions ("missing completely at random", "missing at random" [MAR], "missing not at random") are difficult to interpret and assess. It is not clear how the complexities that arise due to multivariable missingness are being addressed in practice. The aim of this study was to review how missing data are managed and reported in observational studies that use multiple imputation (MI) for causal effect estimation, with a particular focus on missing data summaries, missing data assumptions, primary and sensitivity analyses, and MI implementation.

METHODS

We searched five top general epidemiology journals for observational studies that aimed to answer a causal research question and used MI, published between January 2019 and December 2021. Article screening and data extraction were performed systematically.

RESULTS

Of the 130 studies included in this review, 108 (83%) derived an analysis sample by excluding individuals with missing data in specific variables (e.g., outcome) and 114 (88%) had multivariable missingness within the analysis sample. Forty-four (34%) studies provided a statement about missing data assumptions, 35 of which stated the MAR assumption, but only 11/44 (25%) studies provided a justification for these assumptions. The number of imputations, MI method and MI software were generally well-reported (71%, 75% and 88% of studies, respectively), while aspects of the imputation model specification were not clear for more than half of the studies. A secondary analysis that used a different approach to handle the missing data was conducted in 69/130 (53%) studies. Of these 69 studies, 68 (99%) lacked a clear justification for the secondary analysis.

CONCLUSION

Effort is needed to clarify the rationale for and improve the reporting of MI for estimation of causal effects from observational data. We encourage greater transparency in making and reporting analytical decisions related to missing data.

Neighborhood Socioeconomic Disadvantage Across the Life Course and Premature Mortality

Importance

There are consistent data demonstrating that socioeconomic disadvantage is associated with risk of premature mortality, but research on the relationship between neighborhood socioeconomic factors and premature mortality is limited. Most studies evaluating the association between neighborhood socioeconomic status (SES) and mortality have used a single assessment of SES during middle to older adulthood, thereby not considering the contribution of early life neighborhood SES.

Objective

To investigate the association of life course neighborhood SES and premature mortality.

Design, Setting, and Participants

This cohort study included Black and White participants of the multicenter Atherosclerosis Risk in Communities Study, a multicenter study conducted in 4 US communities: Washington County, Maryland; Forsyth County, North Carolina; Jackson, Mississippi; and the northwestern suburbs of Minneapolis, Minnesota. Participants were followed up for a mean (SD) of 18.8 (5.7) years (1996-2020). Statistical analysis was performed from March 2023 through May 2024.

Exposure

Participants' residential addresses during childhood, young adulthood, and middle adulthood were linked with US Census-based socioeconomic indicators to create summary neighborhood SES scores for each of these life epochs. Neighborhood SES scores were categorized into distribution-based tertiles.

Main Outcomes and Measures

Premature death was defined as all-cause mortality occurring before age 75 years. Multivariable-adjusted Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% CIs.

Results

Among 12 610 study participants, the mean (SD) age at baseline was 62.6 (5.6) years; 3181 (25.2%) were Black and 9429 (74.8%) were White; and 7222 (57.3%) were women. The lowest, compared with the highest tertile, of neighborhood SES score in middle adulthood was associated with higher risk of premature mortality (HR, 1.28; 95% CI, 1.07-1.54). Similar associations were observed for neighborhood SES in young adulthood among women (HR, 1.25; 95% CI, 1.00-1.56) and neighborhood SES in childhood among White participants (HR, 1.25; 95% CI, 1.01-1.56). Participants whose neighborhood SES remained low from young to middle adulthood had an increased premature mortality risk compared with those whose neighborhood SES remained high (HR, 1.25; 95% CI, 1.05-1.49).

Conclusions and Relevance

In this study, low neighborhood SES was associated with premature mortality. The risk of premature mortality was greatest among individuals experiencing persistently low neighborhood SES from young to middle adulthood. Place-based interventions that target neighborhood social determinants of health should be designed from a life course perspective that accounts for early-life socioeconomic inequality.

Structural and functional brain correlates of socioeconomic status across the life span: A systematic review

It is well-established that higher socioeconomic status (SES) is associated with improved brain health. However, the effects of SES across different life stages on brain structure and function is still equivocal. In this systematic review, we aimed to synthesise findings from life course neuroimaging studies that investigated the structural and functional brain correlates of SES across the life span. The results indicated that higher SES across different life stages were independently and cumulatively related to neural outcomes typically reflective of greater brain health (e.g., increased cortical thickness, grey matter volume, fractional anisotropy, and network segregation) in adult individuals. The results also demonstrated that the corticolimbic system was most commonly impacted by socioeconomic disadvantages across the life span. This review highlights the importance of taking into account SES across the life span when studying its effects on brain health. It also provides directions for future research including the need for longitudinal and multimodal research that can inform effective policy interventions tailored to specific life stages.

Antiviral Treatment and Response are Associated With Lower Risk of Dementia Among Hepatitis C Virus-Infected Patients

OBJECTIVE

Eradication of hepatitis C virus (HCV) infection has been linked with improvement in neurocognitive function, but few studies have evaluated the effect of antiviral treatment/ response on risk of dementia. Using data from the Chronic Hepatitis Cohort Study (CHeCS), we investigated how antiviral therapy impacts the risk of developing dementia among patients with HCV.

METHODS

A total of 17,485 HCV patients were followed until incidence of dementia, death, or last follow-up. We used an extended landmark modeling approach, which included time-varying covariates and propensity score justification for treatment selection bias, as well as generalized estimating equations (GEE) with a link function as multinominal distribution for a discrete time-to-event data. Death was considered a competing risk.

RESULTS

After 15 years of follow-up, 342 patients were diagnosed with incident dementia. Patients who achieved sustained virological response (SVR) had significantly decreased risk of dementia compared to untreated patients, with hazard ratios (HRs) of 0.32 (95% CI 0.22-0.46) among patients who received direct-acting antiviral (DAA) treatment and 0.41 (95% CI 0.26-0.60) for interferon-based (IFN) treatment. Risk reduction remained even when patients failed antiviral treatment (HR 0.38, 95% CI 0.38-0.51). Patients with cirrhosis, Black/African American patients, and those without private insurance were at significantly higher risk of dementia.

CONCLUSION

Antiviral treatment independently reduced the risk of dementia among HCV patients, regardless of cirrhosis. Our findings support the importance of initiation antiviral therapy in chronic HCV-infected patients.

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.

"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.

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 lifetime perspective on risk factors for cognitive decline with a special focus on early events

Both Alzheimer's disease and vascular dementia are the result of disease processes that typically develop over several decades. Population studies have estimated that more than half of the risk for dementia is preventable or at least modifiable through behavioral adaptations. The association between these lifestyle factors and the risk of dementia is most evident for exposure in midlife. However, habits formed in middle age often reflect a lifetime of behavior patterns and living conditions. Therefore, individuals who, for example, are able to maintain healthy diets and regular exercise during their middle years are likely to benefit from these cognition-protective habits they have practiced throughout their lives. For numerous adult diseases, significant risks can often be traced back to early childhood. Suboptimal conditions during the perinatal period, childhood and adolescence can increase the risk of adult diseases, including stroke, heart disease, insulin resistance, hypertension and dementia. This review aims at summarizing some of the evidence for dementia risks from a life-time perspective with the goal of raising awareness for early dementia prevention and successful aging.

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.

How Modifiable Are Modifiable Dementia Risk Factors? A Framework for Considering the Modifiability of Dementia Risk Factors

Many risk factors for dementia, identified from observational studies, are potentially modifiable. This raises the possibility that targeting key modifiable dementia risk factors may reduce the prevalence of dementia, which has led to the development of dementia risk reduction and prevention strategies, such as intervention trials or dementia prevention guidelines. However, what has rarely been considered in the studies that inform these strategies is the extent to which modifiable dementia risk factors can (1) be identified by individuals, and (2) be readily modified by individuals. Characteristics of modifiable dementia risk factors such as readiness of identification and targeting, as well as when they should be targeted, can influence the design, or success of strategies for reducing dementia risk. This review aims to develop a framework for classifying the degree of modifiability of dementia risk factors for research studies. The extent to which these modifiable dementia risk factors could be modified by an individual seeking to reduce their dementia risk is determined, as well as the resources that might be needed for both risk factor identification and modification, and whether modification may be optimal in early-life (aged <45 years), midlife (aged 45-65 years) or late-life (aged >65 years). Finally, barriers that could influence the ability of an individual to engage in risk factor modification and, ultimately, dementia risk reduction are discussed.

Investigating the Relationship Between Marital Status and Ethnicity on Neurocognitive Functioning in a Rural Older Population: A Project FRONTIER Study

OBJECTIVES

Research indicates being married is related to better physical and psychological health. Little is known regarding the relationship between marital status and neurocognitive functioning and whether it differs based on ethnicity (Hispanic vs non-Hispanic). This is the first study to examine this relationship in a sample of aging adults in rural Texas.

METHODS

Data from 1,864 participants (Mage = 59.68, standard deviation [SD]age = 12.21), who were mostly Hispanic (n = 1,053), women (n = 1,295), and married (n = 1,125) from Project Facing Rural Obstacles to Healthcare Now Through Intervention, Education, & Research were analyzed. Neuropsychological testing comprised Repeatable Battery for the Assessment of Neuropsychological Status, Trails Making Test, and Clock Drawing. Participants were dichotomized, married, and unmarried.

RESULTS

There was a significant interaction between Hispanic identity and marital status on overall neurocognitive functioning (F(1, 1,480) = 4.79, p < .05, ηp2 = 0.003). For non-Hispanic individuals, married individuals had higher overall neurocognitive functioning compared to unmarried individuals, whereas neurocognitive functioning for Hispanic individuals did not significantly differ between married and unmarried individuals. There were significant main effects as married individuals (M = 84.95, SD = 15.56) had greater overall neurocognitive functioning than unmarried individuals (M = 83.47, SD = 15.86; F(1, 1,480) = 14.67, p < .001, ηp2 = 0.01), Hispanic individuals (M = 78.02, SD = 14.25) had lower overall neurocognitive functioning than non-Hispanic individuals (M = 91.43, SD = 15.07; F(1, 1,480) = 284.99, p < .001, ηp2 = 0.16).

DISCUSSION

Hispanics living in rural areas experience additional stressors that could lead to worse neurocognitive functioning, which is supported by the Lifespan Biopsychosocial Model of Cumulative Vulnerability and Minority Health, which postulates that race/ethnicity/socioeconomic-status-related stressors exacerbate the impact of other life stressors. Reduction of stress on rural Hispanics should be a priority as it could positively affect their neurocognitive functioning.

"We adjusted for race": now what? A systematic review of utilization and reporting of race in American Journal of Epidemiology and Epidemiology, 2020-2021

Race is a social construct, commonly used in epidemiologic research to adjust for confounding. However, adjustment of race may mask racial disparities, thereby perpetuating structural racism. We conducted a systematic review of articles published in Epidemiology and American Journal of Epidemiology between 2020 and 2021 to (1) understand how race, ethnicity, and similar social constructs were operationalized, used, and reported; and (2) characterize good and poor practices of utilization and reporting of race data on the basis of the extent to which they reveal or mask systemic racism. Original research articles were considered for full review and data extraction if race data were used in the study analysis. We extracted how race was categorized, used-as a descriptor, confounder, or for effect measure modification (EMM)-and reported if the authors discussed racial disparities and systemic bias-related mechanisms responsible for perpetuating the disparities. Of the 561 articles, 299 had race data available and 192 (34.2%) used race data in analyses. Among the 160 US-based studies, 81 different racial categorizations were used. Race was most often used as a confounder (52%), followed by effect measure modifier (33%), and descriptive variable (12%). Fewer than 1 in 4 articles (22.9%) exhibited good practices (EMM along with discussing disparities and mechanisms), 63.5% of the articles exhibited poor practices (confounding only or not discussing mechanisms), and 13.5% were considered neither poor nor good practices. We discuss implications and provide 13 recommendations for operationalization, utilization, and reporting of race in epidemiologic and public health research.

Predictive ability of the clock drawing test to detect mild cognitive impairment and dementia over time: Results from the HELIAD study

Objective: We investigated the diagnostic accuracy of the Clock Drawing Test (CDT) in discriminating Mild Cognitive Impairment (MCI) and dementia from normal cognition. Additionally, its clinical utility in predicting the transition from normal cognition to MCI and dementia over the course of several years was explored. Method: In total, 1037 older adults (633 women) who completed the CDT in a baseline assessment were drawn from the population-based HELIAD cohort. Among these, 848 participants were identified as cognitively normal, 142 as having MCI and 47 with dementia during the baseline assessment. Of these individuals, 565 attended the follow-up assessment (mean interval: 3.21 years). ROC curve and binary logistic regression analyses were performed. Results: The CDT exhibited good diagnostic accuracy for the discrimination between dementia and normal cognition (AUC = .879, SN = .813, SP = .778, LR+ = 3.66, LR- = .240, < .001, d = 1.655) and acceptable diagnostic accuracy for the discrimination between dementia and MCI (AUC=.761, SN= .750, SP= .689, LR+ = 2.41, LR- = .362, p < .001, d = 1.003). We found limited diagnostic accuracy, however, for the discrimination between MCI and normal cognition (AUC = .686, SN = .764, SP = .502, LR+ = 1.53, LR- = .470, p < .001, d = .685). Moreover, the CDT significantly predicted the transition from normal cognition to dementia [Exp(B)= 1.257, p = .022], as well as the transition from MCI to normal cognition [Exp(B) = 1.334, p = .023] during the longitudinal investigation. Conclusions: The CDT is a neuropsychological test with acceptable diagnostic accuracy for the discrimination of dementia from MCI and normal cognition. Furthermore, it has an important predictive value for the transition from normal cognition to dementia and from MCI to normal cognition.

Socioeconomic position, modifiable dementia risk and cognitive decline: results of 12-year Maastricht Aging Study

OBJECTIVES

This study investigated whether the association between modifiable dementia risk and rate of cognitive decline differs across socioeconomic status (SES) strata.

DESIGN, SETTING AND PARTICIPANTS

Data were used from Maastricht Aging Study, a prospective cohort study with a 12-year follow-up. The baseline sample consisted of 1023 adults over 40 years old.

MEASUREMENTS

The "LIfestyle for BRAin health" (LIBRA) index was used to assess modifiable dementia risk. Cognitive performance was assessed at baseline, 6 and 12 years, and measured in the domains of information processing speed, executive functioning and verbal memory function. An SES score was calculated from equivalent income and educational level (tertiles). Linear mixed models were used to study the association between LIBRA, SES and their interaction on the rate of cognitive decline.

RESULTS

Participants in the lowest SES tertile displayed more decline in information processing speed (vs. middle SES: X2 = 7.08, P = 0.029; vs. high SES: X2 = 9.49, P = 0.009) and verbal memory (vs. middle SES: X2 = 9.28, P < 0.001; vs. high SES: X2 = 16.68, P < 0.001) over 6 years compared to their middle- and high-SES counterparts. Higher (unhealthier) LIBRA scores were associated with more decline in information processing speed (X2 = 12.66, P = 0.002) over 12 years and verbal memory (X2 = 4.63, P = 0.032) over 6 years. No consistent effect modification by SES on the association between LIBRA and cognition was found.

CONCLUSIONS

Results suggest that lifestyle is an important determinant of cognitive decline across SES groups. Yet, people with low SES had a more unfavorable modifiable risk score suggesting more potential for lifestyle-based interventions.

Dementia Risk and Disadvantaged Neighborhoods

Importance

Residence in a disadvantaged neighborhood may be associated with an increased risk for cognitive impairment and dementia but is understudied in nationally representative populations.

Objective

To investigate the association between the Area Deprivation Index (ADI) and dementia.

Design, Setting, and Participants

Retrospective cohort study within the US Veterans Health Administration from October 1, 1999, to September 30, 2021, with a national cohort of older veterans receiving care in the largest integrated health care system in the United States. For each fiscal year, a 5% random sample was selected from all patients (n = 2 398 659). Patients with missing ADI information (n = 492 721) or missing sex information (n = 6) and prevalent dementia cases (n = 25 379) were excluded. Participants had to have at least 1 follow-up visit (n = 1 662 863). The final analytic sample was 1 637 484.

Exposure

Neighborhoods were characterized with the ADI, which combines several sociodemographic indicators (eg, income, education, employment, and housing) into a census block group-level index of disadvantage. Participants were categorized into ADI rank quintiles by their census block group of residence (higher ADI rank quintile corresponds with more deprivation).

Main Outcome and Measures

Time to dementia diagnosis (using International Classification of Diseases, Ninth Revision and International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes) was estimated with Cox proportional hazards models with age as the time scale, and the sensitivity of the findings was evaluated with Fine-Gray proportional hazards models, accounting for competing risk of death.

Results

Among the 1 637 484 Veterans Health Administration patients, the mean (SD) age was 68.6 (7.7) years, and 1 604 677 (98.0%) were men. A total of 7318 patients were Asian (0.4%), 151 818 (9.3%) were Black, 10 591 were Hispanic (0.6%), 1 422 713 (86.9%) were White, and 45 044 (2.8%) were of other or unknown race and ethnicity. During a mean (SD) follow-up of 11.0 (4.8) years, 12.8% of veterans developed dementia. Compared with veterans in the least disadvantaged neighborhood quintile, those in greater disadvantage groups had an increased risk of dementia in models adjusted for sex, race and ethnicity, and psychiatric and medical comorbid conditions (first quintile = reference; second quintile adjusted hazard ratio [HR], 1.09 [95% CI, 1.07-1.10]; third quintile adjusted HR, 1.14 [95% CI, 1.12-1.15]; fourth quintile adjusted HR, 1.16 [95% CI, 1.14-1.18]; and fifth quintile adjusted HR, 1.22 [95% CI, 1.21-1.24]). Repeating the main analysis using competing risk for mortality led to similar results.

Conclusions and Relevance

Results of this study suggest that residence within more disadvantaged neighborhoods was associated with higher risk of dementia among older veterans integrated in a national health care system.

Racial, ethnic and neighborhood socioeconomic differences in incidence of dementia: A regional retrospective cohort study

BACKGROUND

Evidence on the effects of neighborhood socioeconomic disadvantage on dementia risk in racially and ethically diverse populations is limited. Our objective was to evaluate the relative extent to which neighborhood disadvantage accounts for racial/ethnic variation in dementia incidence rates. Secondarily, we evaluated the spatial relationship between neighborhood disadvantage and dementia risk.

METHODS

In this retrospective study using electronic health records (EHR) at two regional health systems in Northeast Ohio, participants included 253,421 patients aged >60 years who had an outpatient primary care visit between January 1, 2005 and December 31, 2015. The date of the first qualifying visit served as the study baseline. Cumulative incidence of composite dementia outcome, defined as EHR-documented dementia diagnosis or dementia-related death, stratified by neighborhood socioeconomic deprivation (as measured by Area Deprivation Index) was determined by competing-risk regression analysis, with non-dementia-related death as the competing risk. Fine-Gray sub-distribution hazard ratios were determined for neighborhood socioeconomic deprivation, race/ethnicity, and clinical risk factors. The degree to which neighborhood socioeconomic position accounted for racial/ethnic disparities in the incidence of composite dementia outcome was evaluated via mediation analysis with Poisson rate models.

RESULTS

Increasing neighborhood disadvantage was associated with increased risk of EHR-documented dementia diagnosis or dementia-related death (most vs. least disadvantaged ADI quintile HR = 1.76, 95% confidence interval = 1.69-1.84) after adjusting for age and sex. The effect of neighborhood disadvantage on this composite dementia outcome remained after accounting for known medical risk factors of dementia. Mediation analysis indicated that neighborhood disadvantage accounted for 34% and 29% of the elevated risk for composite dementia outcome in Hispanic and Black patients compared to White patients, respectively.

CONCLUSION

Neighborhood disadvantage is related to the risk of EHR-documented dementia diagnosis or dementia-related death and accounts for a portion of racial/ethnic differences in dementia burden, even after adjustment for clinically important confounders.

Association of Childhood and Midlife Neighborhood Socioeconomic Position With Cognitive Decline

Importance

Early-life socioeconomic adversity may be associated with poor cognitive health over the life course.

Objective

To examine the association of childhood and midlife neighborhood socioeconomic position (nSEP) with cognitive decline.

Design, Setting, and Participants

This cohort study included 5711 men and women enrolled in the community-based Atherosclerosis Risk in Communities (ARIC) Study with repeated cognitive data measured over a median 27.0 years (IQR, 26.0-27.9 years) (1990-2019). Statistical analysis was performed from December 2022 through March 2023.

Exposure

Residence addresses for ARIC Study cohort participants were obtained at midlife (1990-1993) and as recalled addresses at 10 years of age (childhood). A composite nSEP z score was created as a sum of z scores for US Census-based measures of median household income; median value of owner-occupied housing units; percentage of households receiving interest, dividend, or net rental income; percentage of adults with a high school degree; percentage of adults with a college degree; and percentage of adults in professional, managerial, or executive occupations. Childhood nSEP and midlife nSEP were modeled as continuous measures and discretized into tertiles.

Main Outcomes and Measures

A factor score for global cognition was derived from a battery of cognitive tests administered at 5 in-person visits from baseline to 2019. The rate of cognitive decline from 50 to 90 years of age was calculated by fitting mixed-effects linear regression models with age as the time scale and adjusted for race, sex, birth decade, educational level, and presence of the apolipoprotein E ε4 allele.

Results

Among 5711 ARIC Study participants (mean [SD] baseline age, 55.1 [4.7] years; 3372 women [59.0%]; and 1313 Black participants [23.0%]), the median rate of cognitive decline was -0.33 SDs (IQR, -0.49 to -0.20 SDs) per decade. In adjusted analyses, each 1-SD-higher childhood nSEP score was associated with a slower (β, -9.2%; 95% CI, -12.1% to -6.4%) rate of cognitive decline relative to the sample median. A comparable association was observed when comparing the highest tertile with the lowest tertile of childhood nSEP (β, -17.7%; 95% CI, -24.1% to -11.3%). Midlife nSEP was not associated with the rate of cognitive decline.

Conclusions and Relevance

In this cohort study of contextual factors associated with cognitive decline, childhood nSEP was inversely associated with trajectories of cognitive function throughout adulthood.

Polygenic Risk Scores for Alzheimer's Disease and General Cognitive Function Are Associated With Measures of Cognition in Older South Asians

Genome-wide association studies (GWAS) conducted in European ancestry (EA) have identified hundreds of single-nucleotide polymorphisms (SNPs) associated with general cognitive function and/or Alzheimer's disease (AD). The association between these SNPs and cognitive function has not been fully evaluated in populations with complex genetic substructure such as South Asians. This study investigated whether SNPs identified in EA GWAS, either individually or as polygenic risk scores (PRSs), were associated with general cognitive function and 5 broad cognitive domains in 932 South Asians from the Diagnostic Assessment of Dementia for the Longitudinal Aging Study in India (LASI-DAD). We found that SNPs identified from AD GWAS were more strongly associated with cognitive function in LASI-DAD than those from a GWAS of general cognitive function. PRSs for general cognitive function and AD explained up to 1.1% of the variability in LASI-DAD cognitive domain scores. Our study represents an important stepping stone toward better characterization of the genetic architecture of cognitive aging in the Indian/South Asian population and highlights the need for further research that may lead to the identification of new variants unique to this population.

Neighbourhood deprivation across eight decades and late-life cognitive function in the Lothian Birth Cohort 1936: a life-course study

INTRODUCTION

although neighbourhood may predict late-life cognitive function, studies mostly rely on measurements at a single time point, with few investigations applying a life-course approach. Furthermore, it is unclear whether the associations between neighbourhood and cognitive test scores relate to specific cognitive domains or general ability. This study explored how neighbourhood deprivation across eight decades contributed to late-life cognitive function.

METHODS

data were drawn from the Lothian Birth Cohort 1936 (n = 1,091) with cognitive function measured through 10 tests at ages 70, 73, 76, 79 and 82. Participants' residential history was gathered with 'lifegrid' questionnaires and linked to neighbourhood deprivation in childhood, young adulthood and mid-to-late adulthood. Associations were tested with latent growth curve models for levels and slopes of general (g) and domain-specific abilities (visuospatial ability, memory and processing speed), and life-course associations were explored with path analysis.

RESULTS

higher mid-to-late adulthood neighbourhood deprivation was associated with lower age 70 levels (β = -0.113, 95% confidence intervals [CI]: -0.205, -0.021) and faster decline of g over 12 years (β = -0.160, 95%CI: -0.290, -0.031). Initially apparent findings with domain-specific cognitive functions (e.g. processing speed) were due to their shared variance with g. Path analyses suggested that childhood neighbourhood disadvantage is indirectly linked to late-life cognitive function through lower education and selective residential mobility.

CONCLUSIONS

to our knowledge, we provide the most comprehensive assessment of the life-course neighbourhood deprivation and cognitive ageing relationship. Living in advantaged areas in mid-to-late adulthood may directly contribute to better cognitive function and slower decline, whereas an advantaged childhood neighbourhood likely affects functioning through cognitive reserves.

Associations Among Loneliness, Purpose in Life and Subjective Cognitive Decline in Ethnoracially Diverse Older Adults Living in the United States

Subjective cognitive decline (SCD), which precedes Mild Cognitive Impairment and dementia, may be affected by purpose in life (PiL) and loneliness in older adults. We investigated associations among PiL, loneliness, and SCD in US Latino (n = 126), Black (n = 74), Asian (n = 33), and White (n = 637) adults. Higher PiL predicted lower SCD in all groups (p-values < .012), except Black participants. Lower loneliness predicted lower SCD in Latino and White groups (p-values < .05), and PiL moderated this association in White adults. PiL and loneliness may play important roles in cognitive decline. Differential predictors of SCD suggest differential targets for preventing cognitive decline and dementia across ethnoracial groups.

Association of neighborhood socioeconomic disadvantage and cognitive impairment

INTRODUCTION

We investigated the association of the area deprivation index (ADI) with cognitive decline, mild cognitive impairment (MCI), and dementia in older adults (≥50 years old). ADI is a neighborhood socioeconomic disadvantage measure assessed at the census block group level.

METHODS

The study included 4699 participants, initially without dementia, with available ADI values for 2015 and at least one study visit in 2008 through 2018. Using logistic regression and Cox proportional hazards models with age as the time scale, we assessed the odds for MCI and the risk for dementia, respectively.

RESULTS

In cognitively unimpaired (CU) adults at baseline, the risk for progression to dementia increased for every decile increase in the ADI state ranking (hazard ratio = 1.06, 95% confidence interval (1.01-1.11), P = .01). Higher ADI values were associated with subtly faster cognitive decline.

DISCUSSION

In older CU adults, higher baseline neighborhood socioeconomic deprivation levels were associated with progression to dementia and slightly faster cognitive decline.

HIGHLIGHTS

The study used area deprivation index, a composite freely available neighborhood deprivation measure. Higher levels of neighborhood deprivation were associated with greater mild cognitive impairment odds. Higher neighborhood deprivation levels were associated with higher dementia risk.

Neighborhood disadvantage and dementia incidence in a cohort of Asian American and non-Latino White older adults in Northern California

INTRODUCTION

Some evidence suggests that neighborhood socioeconomic disadvantage is associated with dementia-related outcomes. However, prior research is predominantly among non-Latino Whites.

METHODS

We evaluated the association between neighborhood disadvantage (Area Deprivation Index [ADI]) and dementia incidence in Asian American (n = 18,103) and non-Latino White (n = 149,385) members of a Northern California integrated health care delivery system aged 60 to 89 at baseline. Race/ethnicity-specific Cox proportional hazards models adjusted for individual-level age, sex, socioeconomic measures, and block group population density estimated hazard ratios (HRs) for dementia.

RESULTS

Among non-Latino Whites, ADI was associated with dementia incidence (most vs. least disadvantaged ADI quintile HR = 1.09, 95% confidence interval [CI] = 1.02-1.15). Among Asian Americans, associations were close to null (e.g., most vs. least disadvantaged ADI quintile HR = 1.01, 95% CI = 0.85-1.21).

DISCUSSION

ADI was associated with dementia incidence among non-Latino Whites but not Asian Americans. Understanding the potentially different mechanisms driving dementia incidence in these groups could inform dementia prevention efforts.

Consideration of sex and gender in Alzheimer's disease and related disorders from a global perspective

Sex or gender differences in the risk of Alzheimer's disease and related dementias (ADRD) differ by world region, suggesting that there are potentially modifiable risk factors for intervention. However, few epidemiological or clinical ADRD studies examine sex differences; even fewer evaluate gender in the context of ADRD risk. The goals of this perspective are to: (1) provide definitions of gender, biologic sex, and sexual orientation. and the limitations of examining these as binary variables; (2) provide an overview of what is known with regard to sex and gender differences in the risk, prevention, and diagnosis of ADRD; and (3) discuss these sex and gender differences from a global, worldwide perspective. Identifying drivers of sex and gender differences in ADRD throughout the world is a first step in developing interventions unique to each geographical and sociocultural area to reduce these inequities and to ultimately reduce global ADRD risk. HIGHLIGHTS: The burden of dementia is unevenly distributed geographically and by sex and gender. Scientific advances in genetics and biomarkers challenge beliefs that sex is binary. Discrimination against women and sex and gender minority (SGM) populations contributes to cognitive decline. Sociocultural factors lead to gender inequities in Alzheimer's disease and related dementias (ADRD) worldwide.

Area Deprivation Index as a Surrogate of Resilience in Aging and Dementia

Area deprivation index (ADI), a tool used to capture the multidimensional neighborhood socioeconomic disadvantage across populations, is highly relevant to the field of aging and Alzheimer’s disease and Alzheimer’s disease related dementias (AD/ADRD). ADI is specifically relevant in the context of resilience, a broad term used to explain why some older adults have better cognitive outcomes than others. The goal of this mini-review is three-fold: (1) to summarize the current literature on ADI and its link to cognitive impairment outcomes; (2) suggest possible mechanisms through which ADI may have an impact on AD/ADRD outcomes, and (3) discuss important considerations when studying relations between ADI and cognitive as well as brain health. Though difficult to separate both the upstream factors that emerge from high (worse) ADI and all the mechanisms at play, ADI is an attractive proxy of resilience that captures multifactorial contributors to the risk of dementia. In addition, a life-course approach to studying ADI may allow us to capture resilience, which is a process developed over the lifespan. It might be easier to build, preserve or improve resilience in an environment that facilitates instead of hindering physical, social, and cognitively beneficial activities. Neighborhood disadvantage can adversely impact cognitive impairment risk but be at the same time a modifiable risk factor, amenable to policy changes that can affect communities.

Individual Life-Course Socioeconomic Position and Hearing Aid Use in the Atherosclerosis Risk in Communities Study

BACKGROUND

To measure the association between individual life-course socioeconomic position (SEP) and hearing aid use, we examined childhood and adulthood socioeconomic variables collected at the Atherosclerosis Risk in Communities (ARIC) study baseline visit (1987-1989)/Life Course Socioeconomic Status study (2001-2002) and hearing aid use data collected at visit 6 (2016-2017).

METHODS

ARIC is a prospective cohort study of older adults (45-64 years) recruited from 4 U.S. communities. This analysis included a subset of 2 470 participants with hearing loss at visit 6 (≥25 decibels hearing level [dB HL] better-ear) with complete hearing aid use data. Childhood SEP variables included parental education, parental occupation, and parental home ownership. Young and older adulthood SEP variables included income, education, occupation, and home ownership. Each life epoch was assigned a score ranging from 0 to 5 and then summed to calculate the individual cumulative SEP score. Multivariable-adjusted logistic regression was used to estimate the association between individual cumulative SEP and hearing aid use. Missing SEP scores were imputed for participants with incomplete socioeconomic data.

RESULTS

Of the 2 470 participants in the analytic cohort (median [interquartile interval] age 79.9 [76.7-84.0], 1 330 [53.8%] women, 450 [18.2%] Black), 685 (27.7%) participants reported hearing aid use. Higher cumulative SEP was positively associated with hearing aid use (odds ratio [OR] = 1.09, 95% confidence interval [CI]: 1.04-1.14), and slightly stronger for childhood (OR = 1.09, 95% CI: 1.00-1.20) than older adulthood SEP score (OR = 1.06, 95% CI: 0.95-1.18).

CONCLUSIONS

In this community-based cohort of older adults with hearing loss, higher individual life-course SEP was positively associated with hearing aid use.

Association of Neighborhood-Level Socioeconomic Measures With Cognition and Dementia Risk in Australian Adults

IMPORTANCE

Up to 40% of dementia cases are potentially preventable; therefore, it is important to identify high-risk groups to whom resources could be targeted for maximal impact in preventing late-life dementia. The association of neighborhood-level socioeconomic status (SES) with cognition and dementia risk is not well known, particularly in midlife when late-life dementia may still be preventable through established interventions, such as blood pressure management.

OBJECTIVE

To examine whether neighborhood-level SES is associated with differences in cognitive performance and dementia risk scores.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study analyzed data collected between November 17, 2016, and April 14, 2020, from 4656 participants in the longitudinal population-based Healthy Brain Project cohort. This large online cohort comprised community-dwelling individuals geographically dispersed across Australia. Participants were aged 40 to 70 years without dementia or other major neurological conditions.

EXPOSURES

Neighborhood-level SES was computed by matching participants' residential addresses to the Australian Bureau of Statistics Index of Relative Socio-economic Advantage and Disadvantage (IRSAD). Postcodes provided by each participant were used to derive an IRSAD score that ranked participants according to deciles of neighborhood-level SES (range, 1-10, with higher deciles indicating greater socioeconomic advantage); neighborhoods in deciles 1 to 7 were considered to have low or intermediate SES, and neighborhoods in deciles 8 to 10 were considered to have high SES.

MAIN OUTCOMES AND MEASURES

Dementia risk estimated using the dementia risk score from the Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) tool (n = 4656) and cognitive composite scores for memory and attention measured by the Cogstate Brief Battery (n = 2181).

RESULTS

Of 4656 participants (mean [SD] age, 56.1 [7.2] years; 3445 women [74.0%]), 2688 individuals (57.7%) lived in areas with high neighborhood-level SES (IRSAD decile ≥8), and 1968 (42.3%) lived in areas with low or intermediate neighborhood-level SES (IRSAD decile <8), with 1263 individuals (27.1%) residing in rural or regional areas. A total of 6 participants (0.1%) identified as African, 121 (2.6%) as Asian, 57 (1.2%) as Indigenous Australian, 24 (0.5%) as Latin American, 9 (0.2%) as Pacific Islander, 3671 (78.8%) as White or European, and 768 (16.5%) indicated other race (not specified). Each decile unit increase in neighborhood-level SES was associated with a lower CAIDE dementia risk score after adjustment for race and rurality (β [SE] = -0.070 [0.019]; P = .004). Each decile unit increase was also associated with better memory (β [SE] = 0.022 [0.006]; P = .006) but not with better attention (β [SE] = 0.009 [0.007]; P = .34), as measured by Cogstate Brief Battery composite z scores after adjustment for age, sex, race, years of education, and rurality. When comparing memory performance between individuals with IRSAD scores higher and lower than decile 8, neighborhood-level SES interacted with age (F1-2171 = 6.33; P = .02) and CAIDE dementia risk scores (F1-2173 = 4.02; P = .08). Differences in memory between neighborhood-level SES categories were larger among participants who were older and had a higher risk of dementia.

CONCLUSIONS AND RELEVANCE

In this study, higher neighborhood-level SES was associated with better memory and lower dementia risk scores. These results suggest that efforts to lower dementia risk factors in disadvantaged areas are needed to curtail the increasing burden of dementia and that inclusion of individuals living in areas with lower SES in research on dementia is warranted to improve understanding and potential interventions.

Current and future burdens of heat-related dementia hospital admissions in England

INTRODUCTION

The impacts of a changing climate on current and future dementia burdens have not been widely explored.

METHODS

Time-series negative binomial regression analysis was used to assess acute associations between daily ambient temperature and counts of emergency admissions for dementia in each Government region of England, adjusting for season and day-of-week. Using the latest climate and dementia projections data, we then estimate future heat-related dementia burdens under a high emission scenario (Representative Concentration Pathway (RCP8.5), where global greenhouse gas (GHG) emissions continue to rise, and a low emissions scenario (RCP2.6), where GHG emissions are sizeably reduced under a strong global mitigation policy.

RESULTS

A raised risk associated with high temperatures was observed in all regions. Nationally, a 4.5% (95% Confidence interval (CI) 2.9%-6.1%) increase in risk of dementia admission was observed for every 1 °C increase in temperature above 17 °C associated with current climate. Under a high emissions scenario, heat-related admissions are projected to increase by almost 300% by 2040 compared to baseline levels.

CONCLUSIONS

People living with dementia should be considered a high-risk group during hot weather. Our results support arguments for more stringent climate change mitigation policies.

Stroke Belt birth state and late-life cognition in the Study of Healthy Aging in African Americans (STAR)

PURPOSE

We examined the association of Stroke Belt birth state with late-life cognition in The Study of Healthy Aging in African Americans (STAR).

METHODS

STAR enrolled 764 Black Americans ages 50+ who were long-term Kaiser Permanente Northern California members. Participants completed Multiphasic Health Check-ups (MHC; 1964-1985) where early-life overweight/obesity, hypertension, diabetes, and hyperlipidemia were measured. At STAR (2018), birth state, self-reported early-life socioeconomic status (SES), and executive function, verbal episodic memory, and semantic memory scores were collected. We used linear regression to examine the association between Stroke Belt birth and late-life cognition adjusting for birth year, gender, and parental education. We evaluated early-life SES and cardiovascular risk factors (CVRF) as potential mechanisms.

RESULTS

Twenty-seven percent of participants were born in the Stroke Belt with a mean age of 69 (standard deviation = 9) at STAR. Stroke Belt birth was associated with worse late-life executive function (β [95% confidence interval]: -0.18 [-0.33, -0.02]) and semantic memory (-0.37 [-0.53, -0.21]), but not verbal episodic memory (-0.04 [-0.20, 0.12]). Adjustment for SES and CVRF attenuated associations of Stroke Belt birth with cognition (executive function [-0.05 {-0.25, 0.14}]; semantic memory [-0.28 {-0.49, -0.07}]).

CONCLUSIONS

Black Americans born in the Stroke Belt had worse late-life cognition than those born elsewhere, underscoring the importance of early-life exposures on brain health.

Dementia and disadvantage in the USA and England: population-based comparative study

OBJECTIVES

To compare dementia prevalence and how it varies by socioeconomic status (SES) across the USA and England.

DESIGN

Population-based comparative study.

SETTING

Non-Hispanic whites aged over 70 population in the USA and England.

PARTICIPANTS

Data from the Health and Retirement Study and the English Longitudinal Study of Ageing, which are harmonised, nationally representative panel studies. The sample includes 5330 and 3147 individuals in the USA and England, respectively.

MAIN OUTCOME MEASURES

Between country differences in age-gender standardised dementia prevalence, across the SES gradient. Dementia prevalence was estimated in each country using an algorithm based on an identical battery of demographic, cognitive and functional measures.

RESULTS

Dementia prevalence is higher among the disadvantaged in both countries, with the USA being more unequal according to four measures of SES. Overall prevalence was lower in England at 9.7% (95% CI 8.9% to 10.6%) than the USA at 11.2% (95% CI 10.6% to 11.8%), a difference of 1.4 percentage points (pp) (p=0.0055). Most of the between country difference is driven by the bottom of the SES distribution. In the lowest income decile individuals in the USA had 7.3 pp (p<0.0001) higher prevalence than in England. Once past health factors and education were controlled for, most of the within country inequalities disappeared; however, the cross-country difference in prevalence for those in lowest income decile remained disproportionately high.

CONCLUSIONS

There is inequality in dementia prevalence according to income, wealth and education in both the USA and England. England has lower dementia prevalence and a less steep SES gradient. Most of the cross-country difference is concentrated in the lowest SES group, which provides evidence that disadvantage in the USA is a disproportionately high risk factor for dementia.

Education and Cardiovascular Health as Effect Modifiers of APOE ε4 on Dementia: The Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Both education and cardiovascular risk factors are strongly associated with dementia risk. However, it is not clear whether these associations persist or vary among individuals with high genetic risk for Alzheimer's Disease. We examined the interactive relationship between lifestyle and genetic dementia risk factors in a prospective cohort study.

METHODS

Our data came from the Atherosclerosis Risk in Communities study participants (n=13,715; baseline age 45-64; 25% Black; 55% female), who were followed for incident dementia from 1987 through 2017. We used Cox proportional hazard models to estimate the risk of dementia (ascertained through in-person examination, telephone cognitive screeners, and/or hospital and death records) associated with baseline education and cardiovascular risk factors (measured using the American Heart Association's "Life Simple 7") among ε4 carriers and non-carriers separately. We also examined differences by race and sex.

RESULTS

2,226 incident dementia cases occurred over a median 25 years of follow-up. Lower educational attainment and poorer cardiovascular health were associated with greater risk of incident dementia. There was an education by APOE status interaction (p=0.005) whereby the association of education and dementia was weaker for ε4 carriers (HR college graduates vs. less than high school: 0.71 (0.59-0.84) than non-carriers (0.54 (0.47-0.63)). There was no interaction between APOE status and cardiovascular health on dementia risk. These relationships did not vary significantly by race or sex.

CONCLUSIONS

Education and cardiovascular health were associated with lower dementia risk regardless of APOE genotype, though the protective effects of education were somewhat diminished among ε4 carriers.

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.

Effect of Social Determinants of Health on Cognition and Risk of Alzheimer Disease and Related Dementias

Social determinants of health are the conditions in which people are born, work, live, and age and the wider set of forces and systems that shape the conditions of daily life. They affect every area of life, particularly health and health care. There is increasing focus on modifiable factors that affect cognition and risk of Alzheimer disease and related dementias (ADRDs). This article examines the impact of various social determinants of health, which are potentially reversible, on the incidence, prevalence, and risk of ADRDs and cognition. Various social determinants of health affect cognition and risk of ADRDs. Lower socioeconomic status (SES) and less education are associated with a higher incidence of ADRDs, whereas higher SES and education level appear to be protective, leading to a deceleration of time to diagnosis. In terms of employment, manual labor is associated with a higher risk of ADRDs. Higher body mass index in midlife and a decreasing body mass index in old age are associated with a higher risk of ADRDs. Furthermore, lower food security in early and late life is associated with a higher risk of ADRD diagnosis. Neighborhoods that are economically disadvantaged with fewer physical resources are associated with a higher risk of ADRDs. Higher levels of social engagement have a protective effect on diagnosis of ADRDs. Higher levels of stress are associated with a higher likelihood of developing ADRDs. Early-life adversity is associated with an increased risk of ADRDs, and further work in this area will be illuminating. Racial discrimination also leads to higher risk of ADRDs through the direct effect of discrimination and indirectly through lower SES, educational level, employment, and residential segregation. With an aim of reducing of ADRDs, future work in enhancing education, improving socioeconomic conditions, work, and neighborhood environments, and eliminating racial discrimination could potentially have a drastic impact.

Life Course Socioeconomic Status and Risk of Hospitalization for Heart Failure or Atrial Fibrillation in The Moli-Sani Study Cohort

We investigated the association of cumulative socioeconomic disadvantage (CSD) and socioeconomic (SES) trajectories across life course with the risk of first hospitalization for heart failure (HF) or atrial fibrillation (AF) and tested some biological mechanisms in explaining such associations. Longitudinal analysis on 21,756 HF- and AF-free subjects recruited in the Moli-sani Study (2005-2010; Italy) and followed up for 8.2 years. CSD was computed using childhood SES, education and adulthood SES indicators, and the same were used to define overall trajectories. High disadvantage across life course (CSD≥8) posed subjects at increased risk of HF (Hazard ratio [HR]=2.58; 95%CI 1.78, 3.74) or AF (HR=1.57;1.05,2.33), as compared to low CSD. All explanatory factors accounted for 18.5% and 24% of the excess of HF and AF risks, respectively, associated with CSD. For subjects with low childhood SES, advancements in education lowered risk of HF (HR=0.70;0.48, 1.02) or AF (HR=0.50;0.28, 0.89), whereas achievements of adulthood SES were unlikely to contribute to disease reduction. In conclusion, a life-course disadvantaged SES is an important predictor of first hospitalization for HF and AF; known risk factors partially explained the SES-disease gradient. Upwardly mobile groups are likely to mitigate the effect of poor childhood circumstances especially through educational advancement.

Genetically Predicted Telomere Length and Its Relationship With Alzheimer's Disease

Are shorter telomeres causal risk factors for Alzheimer’s disease (AD)? This study aimed to examine if shorter telomeres were causally associated with a higher risk of AD using Mendelian randomization (MR) analysis. Two-sample MR methods were applied to the summary effect sizes and standard errors from a genome-wide association study for AD. Twenty single nucleotide polymorphisms of genome-wide significance were selected as instrumental variables for leukocyte telomere length. The main analyses were performed primarily using the random-effects inverse-variance weighted method and complemented with the other three methods: weighted median approaches, MR-Egger regression, and weighted mode approach. The intercept of MR-Egger regression was used to assess horizontal pleiotropy. We found that longer telomeres were associated with lower risks of AD (odds ratio = 0.79, 95% confidence interval: 0.67, 0.93, P = 0.004). Comparable results were obtained using weighted median approaches, MR-Egger regression, and weighted mode approaches. The intercept of the MR-Egger regression was close to zero. This may show that there was not suggestive of horizontal pleiotropy. Our findings provided additional evidence regarding the putative causal association between shorter telomere length and the higher risk of AD.

Medical and Social Determinants of Brain Health and Dementia in a Multicultural Community Cohort of Older Adults

BACKGROUND

Socioeconomic status (SES), race, ethnicity, and medical comorbidities may contribute to Alzheimer's disease and related disorders (ADRD) health disparities.

OBJECTIVE

Analyze effects of social and medical determinants on cognition in 374 multicultural older adults participating in a community-based dementia screening program.

METHODS

We used the Montreal Cognitive Assessment (MoCA) and AD8 as measures of cognition, and a 3-way race/ethnicity variable (White, African American, Hispanic) and SES (Hollingshead index) as predictors. Potential contributors to health disparities included: age, sex, education, total medical comorbidities, health self-ratings, and depression. We applied K-means cluster analyses to study medical and social dimension effects on cognitive outcomes.

RESULTS

African Americans and Hispanics had lower SES status and cognitive performance compared with similarly aged Whites. We defined three clusters based on age and SES. Cluster #1 and #3 differed by SES but not age, while cluster #2 was younger with midlevel SES. Cluster #1 experienced the worse health outcomes while cluster #3 had the best health outcomes. Within each cluster, White participants had higher SES and better health outcomes, African Americans had the worst physical performance, and Hispanics had the most depressive symptoms. In cross-cluster comparisons, higher SES led to better health outcomes for all participants.

CONCLUSION

SES may contribute to disparities in access to healthcare services, while race and ethnicity may contribute to disparities in the quality and extent of services received. Our study highlights the need to critically address potential interactions between race, ethnicity, and SES which may better explain disparities in ADRD health outcomes.