Association of Demographic and Early-Life Socioeconomic Factors by Birth Cohort With Dementia Incidence Among US Adults Born Between 1893 and 1949

Cognitive impairment and dementia-Are they linked to childhood health and socioeconomic status? A systematic review

BACKGROUND

Dementia is a major public health concern, with its incidence rising as the population ages. Recent studies suggest links between childhood health, socioeconomic status, and later-life cognitive impairment and dementia, though findings remain inconclusive. This systematic review evaluates the influence of childhood health and socioeconomic status on cognitive impairment and dementia.

METHOD AND FINDINGS

A systematic search conducted in MEDLINE, CiNAHL, and PsycINFO in December 2024 identified 44 studies matching our inclusion criteria. Findings are presented under five key themes: (1) childhood health, (2) childhood educational attainment, (3) family socioeconomic and educational factors, (4) childhood experiences, and (5) childhood reading habits and social interactions.

CONCLUSION

Our results highlight the need for further longitudinal studies to establish causal relationships between early-life risk factors and later cognitive decline. Policymakers should prioritize early childhood development programs that integrate health, nutrition, education, and social support to help mitigate cognitive impairment and dementia in later life.

Number of children and risk of dementia: a cohort study

BACKGROUND

Findings on the link between the number of children and dementia risk are inconsistent, mostly studied in females, suggesting pregnancy-related changes may be a key factor in this association.

METHODS

The Adult Changes in Thought Study is a cohort of adults aged ≥65 years from Kaiser Permanente Washington. The primary exposure was the number of children (0, 1, 2, 3 or ≥4), and the outcome was an incident dementia diagnosis. Cox proportional-hazards models were adjusted for demographic and early-life socioeconomic confounders. Models were then stratified by sex and by birth year <1928 versus ≥1928.

RESULTS

Among 4668 participants (average age at enrolment 74.1±SD 6.3 years; 59% female), 967 (21%) had 0 children, 484 (10%) had one child, 1240 (27%) had two children, 968 (21%) had three children and 1009 (22%) had four or more children. We found no association between the number of children and dementia overall or after stratification by birth cohort. When stratified by sex and adjusting for confounders, having ≥4 children compared with two children was associated with a higher rate of dementia in males (HR=1.31, 95% CI 1.01 to 1.71).

CONCLUSIONS

The number of children was not consistently associated with the risk of dementia. We observed a greater risk of dementia only among males who had ≥4 children, with the lower bound of the 95% CI marginally exceeding 1. These findings suggest that the number of children may influence the risk of dementia through other than pregnancy-related pathways.

Brain health equity and the influence of social determinants across the life cycle

Social determinants of health are social, economic and environmental factors known to influence health and development of infants, children and adults. Advancing equity in brain health relies upon interdisciplinary collaboration and recognition of the impact of social determinants on brain health through the lifespan and across generations. Critical periods of fetal, infant and early childhood development encompass intrinsic genetic and extrinsic environmental influences with complex gene-environment interactions. This review discusses the influence of social determinants on the continuum of brain health from preconception and pregnancy health, through fetal, infant and childhood neurodevelopment into adulthood. Opportunities for intervention to address the social determinants of brain health across the life cycle are highlighted.

Association of adverse childhood experiences with poor health condition among middle-aged and elderly adults in the United States: A nationally retrospective cohort study

BACKGROUND

The specific effects of adverse childhood experiences (ACEs) in adulthood and senectitude were less known. We aim to examine the relationship between early ACEs and overall health condition as well as specific dimensions in the middle-aged and elderly population.

METHODS

In the 2019-2021 Behavioral Risk Factor Surveillance System Study, robust Poisson regression models were used to estimate the relationship between ACE exposure and current health status among adults aged 45 ≥ years.

RESULTS

Of the 195,472 participants, 53.8 % were female and the mean age was 65.0 years. Compared to populations without ACE, ACE exposures were more significantly associated with depression (PR: 2.03, 95 %CI: 1.94-2.21), frequent mental health (PR: 1.85, 95 %CI: 1.74-1.97) and subject cognitive decline (PR: 1.99, 95 %CI:1.85-2.14) than with physical health (PR: 1.37, 95 %CI: 1.32-1.44), with dose-response patterns. The association with mental disorder was especially significant among the elderly population.

CONCLUSION

Early ACEs are associated with adverse health outcomes that persist into later life, particularly mental disorders and cognitive decline. Poor mental health may indirectly influence associations with ACEs and cognitive decline as well as physical health. Our findings emphasize the importance of lifelong psychological screening and support for the ACE-exposed middle-aged and elderly population.

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.

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.

Dental decision-making for persons with dementia: A systematic narrative review

Dental decision-making represents the establishment of a common understanding between the dental professional and the recipient of the intervention, which determines oral healthcare and dental treatment policies. Dental decision-making for persons with dementia can be challenging, and there have been no systematic reviews on this topic. Therefore, this systematic narrative review aimed to identify the current state of dental decision-making in persons with dementia. Literature search was performed using PubMed, Web of Science, Cochrane Library, CINAHL, and Google Scholar databases. Through the process of research selection, 7 articles with a high risk of bias were included in this study. This review clarified that there is limited information on the dental decision-making processes for persons with dementia. In conclusion, although this may be difficult due to different medical and socioeconomic conditions, the dilemma between the need to establish evidence for dental decision-making and medical ethics that prioritize a patient-centered position should be discussed globally in the future.

Once upon a time, the Amyloid Cascade Hypothesis

Recent trials with monoclonal antibodies targeting amyloid-β (Aβ) in Alzheimer's disease (AD) have sparked a renewed interest in disease-modifying therapies. Despite their promise, these trials leave the issue open and posit some doubts about the validity of the Amyloid Cascade Hypothesis (ACH). While some scores of neurocognitive tests improved upon treatment, real-world clinical benefits were minimal. This Viewpoint discusses additional, often overlooked findings from these trials. We also emphasize the multifactorial nature of AD and the need for a broader research perspective beyond the simplistic disease model provided by the ACH.

Sex differences in dementia risk and risk factors: Individual-participant data analysis using 21 cohorts across six continents from the COSMIC consortium

INTRODUCTION

Sex differences in dementia risk, and risk factor (RF) associations with dementia, remain uncertain across diverse ethno-regional groups.

METHODS

A total of 29,850 participants (58% women) from 21 cohorts across six continents were included in an individual participant data meta-analysis. Sex-specific hazard ratios (HRs), and women-to-men ratio of hazard ratios (RHRs) for associations between RFs and all-cause dementia were derived from mixed-effect Cox models.

RESULTS

Incident dementia occurred in 2089 (66% women) participants over 4.6 years (median). Women had higher dementia risk (HR, 1.12 [1.02, 1.23]) than men, particularly in low- and lower-middle-income economies. Associations between longer education and former alcohol use with dementia risk (RHR, 1.01 [1.00, 1.03] per year, and 0.55 [0.38, 0.79], respectively) were stronger for men than women; otherwise, there were no discernible sex differences in other RFs.

DISCUSSION

Dementia risk was higher in women than men, with possible variations by country-level income settings, but most RFs appear to work similarly in women and men.

Propensity Scores in Health Disparities Research: The Example of Cognitive Aging and the Hispanic Paradox

BACKGROUND

Individuals of Mexican ancestry in the United States experience substantial socioeconomic disadvantages compared with non-Hispanic white individuals; however, some studies show these groups have similar dementia risk. Evaluating whether migration selection factors (e.g., education) associated with risk of Alzheimer disease and related dementia (ADRD) explain this paradoxical finding presents statistical challenges. Intercorrelation of risk factors, common with social determinants, could make certain covariate patterns very likely or unlikely to occur for particular groups, which complicates their comparison. Propensity score (PS) methods could be leveraged here to diagnose nonoverlap and help balance exposure groups.

METHODS

We compare conventional and PS-based methods to examine differences in cognitive trajectories between foreign-born Mexican American, US-born Mexican American, and US-born non-Hispanic white individuals in the Health and Retirement Study (1994-2018). We examined cognition using a global measure. We estimated trajectories of cognitive decline from linear mixed models adjusted for migration selection factors also associated with ADRD risk conventionally or with inverse probability weighting. We also employed PS trimming and match weighting.

RESULTS

In the full sample, where PS overlap was poor, unadjusted analyses showed both Mexican ancestry groups had worse baseline cognitive scores but similar or slower rates of decline compared with non-Hispanic white adults; adjusted findings were similar, regardless of method. Focusing analyses on populations where PS overlap was improved (PS trimming and match weighting) did not alter conclusions.

CONCLUSIONS

Attempting to equalize groups on migration selection and ADRD risk factors did not explain paradoxical findings for Mexican ancestry groups in our study.

Direct Effect of Life-Course Socioeconomic Status on Late-Life Cognition and Cognitive Decline in the Rush Memory and Aging Project

The role of socioeconomic status (SES) across the life course in late-life cognition is unclear. We tested the hypotheses that: 1) High SES in childhood, young adulthood, midlife, and late life have independent causal effects on higher cognition level and slower cognitive decline; 2) Compared with stable low SES (referent), stable high SES has the largest estimated effect for higher cognition level and slower decline among life-course SES combinations. The Rush Memory and Aging Project enrolled 1,940 dementia-free older adults in northeastern Illinois (1997-2018). We used inverse probability-weighted marginal structural models to estimate the joint and independent effect of each life-course SES on global and domain-specific cognition. A total of 1,746 participants had, on average, 6 years of follow-up. High SES at each life-course stage starting in young adulthood had a protective estimated effect on global and domain-specific cognition intercepts. Compared with consistently low SES, consistently high SES (β = 0.64, 95% confidence interval: 0.48, 0.93) and high SES beyond childhood (β = 0.64, 95% confidence interval: 0.47, 0.83) had the largest benefit for global cognition intercepts. None of the life-course SES measures influenced rate of global or domain-specific decline. Additional understanding of life-course SES components influencing cognitive level is warranted.

Trends in Postmortem Neurodegenerative and Cerebrovascular Neuropathologies Over 25 Years

Importance

With rapid aging of the US population, understanding trends over time in dementia occurrence is essential to public health planning and intervention; this understanding includes trends in neuropathologies underlying clinical dementia.

Objective

To characterize trends in pathways underlying dementia by examining prevalence of postmortem neuropathologies in birth cohorts across 25 years.

Design, Setting, and Participants

Two longitudinal cohorts, the Religious Orders Study and the Rush Memory and Aging Project, with autopsy data from 1997 to 2022 with up to 27 years follow-up were analyzed. Deceased individuals with complete postmortem neuropathology evaluations were included, and 177 individuals with most distant (<1905) or recent (>1930) years of birth were excluded.

Exposures

Four categories of year of birth: 1905-1914, 1915-1919, 1920-1924, and 1925-1930.

Main Outcomes and Measures

Outcomes included pathologic diagnosis of Alzheimer disease (AD), global AD pathology, amyloid load, tau tangles, neocortical Lewy bodies, limbic-predominant age-related TDP-43 encephalopathy neuropathological change, atherosclerosis, arteriolosclerosis, gross chronic infarcts, and chronic microinfarcts. For comparison, pathologies in each birth epoch were age-standardized to age distribution of the cohorts. χ2 Tests were used for categorical outcomes, and analysis of variance was used to compare means across birth epochs.

Results

Overall, 1554 participants were examined (510 [33%] male; median [range] age at death, 90 [66-108] years). Participants were distributed fairly evenly across birth epochs (1905-1914: n = 374; 1915-1919: n = 360; 1920-1924: n = 466; 1925-1930: n = 354). Across year of birth groups, no differences were found in prevalence of pathologic AD diagnosis; age-standardized prevalence fluctuated between 62% and 68% in the birth cohorts (χ2 test: P = .76 across birth epochs). Similarly, no differences were found in mean levels of global AD pathology, although there was greater density specifically of tau tangles in later birth cohorts (eg, age-standardized mean [SD], 1.53 [1.20] years for the 1905-1914 cohort and 1.87 [1.47] years for the 1925-1930 cohort; analysis of variance test: P = .01 across birth cohorts). There were no differences over time in other neurodegenerative pathologies. In contrast, atherosclerosis and arteriosclerosis were dramatically lower over time; for example, age-standardized prevalence of moderate to severe atherosclerosis ranged from 54% among those born from 1905-1914 to 22% for 1925-1930 (χ2 test: P < .001 across birth epochs).

Conclusion and Relevance

In this study, few differences in neurodegenerative pathologies were found, but there may be worse levels of tau tangles across birth cohorts over 25 years. This indicates that any improvements over time in clinical dementia observed by cohorts are likely in part associated with improved resilience to pathology rather than reduced AD pathology. Finally, vessel pathologies were markedly lower over birth cohorts, indicating the assocation with brain health of populationwide improvements in several vascular risk factors.

A call to address structural barriers to Hispanic/Latino representation in clinical trials on Alzheimer's disease and related dementias: A micro-meso-macro perspective

Introduction

This perspective paper addresses the US Hispanic/Latino (herein, Latino) experience with regards to a significant public health concern-the underrepresentation of Latino persons in Alzheimer's disease and related dementias (AD/ADRD) clinical trials. Latino individuals are at increased risk for AD/ADRD, experience higher disease burden, and low receipt of care and services. We present a novel theoretical framework-the Micro-Meso-Macro Framework for Diversifying AD/ADRD Trial Recruitment-which considers multi-level barriers and their impact on Latino trial recruitment.

Methods

Based on a review of the peer-reviewed literature and our lived experience with the Latino community, we drew from our interdisciplinary expertise in health equity and disparities research, Latino studies, social work, nursing, political economy, medicine, public health, and clinical AD/ADRD trials. We discuss factors likely to impede or accelerate Latino representation, and end with a call for action and recommendations for a bold path forward.

Results

In the 200+ clinical trials conducted with over 70,000 US Americans, Latino participants comprise a fraction of AD/ADRD trial samples. Efforts to recruit Latino participants typically address individual- and family-level factors (micro-level) such as language, cultural beliefs, knowledge of aging and memory loss, limited awareness of research, and logistical considerations. Scientific efforts to understand recruitment barriers largely remain at this level, resulting in diminished attention to upstream institutional- and policy-level barriers, where decisions around scientific policies and funding allocations are ultimately made. These structural barriers are comprised of inadequacies or misalignments in trial budgets, study protocols, workforce competencies, healthcare-related barriers, criteria for reviewing and approving clinical trial funding, criteria for disseminating findings, etiological focus and social determinants of health, among others.

Conclusion

Future scientific work should apply and test the Micro-Meso-Macro Framework for Diversifying AD/ADRD Trial Recruitment to examine structural recruitment barriers for historically underrepresented groups in AD/ADRD research and care.

2023 Alzheimer's disease facts and figures

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

Adverse childhood experiences and their impacts on subsequent depression and cognitive impairment in Chinese adults: A nationwide multi-center study

BACKGROUND

Adverse childhood experiences (ACE_S) are prevalent and have long-lasting effects. This study explored how ACE exposure is associated with subsequent depression and cognitive impairment and whether sociodemographic characteristics modify that association.

METHOD

This study used data on 14,484 participants of the 2015 China Health and Retirement Longitudinal Study (CHARLS) and 2014 CHARLS life history survey. Depression was assessed using the 10-item Center for Epidemiologic Studies Depression scale. Cognitive performance was evaluated via three composite measures: episodic memory, mental intactness, and global cognition. Twelve ACE indicators were measured using a validated questionnaire. Multiple regression models and stratified analyses explored the relationship between ACE_S and subsequent depression and cognitive impairment, as well as potential modifiers.

RESULTS

Compared with individuals without ACE_S, those who experienced four or more ACE_S had a higher risk of subsequent depression (adjusted odds ratio, aOR = 2.65, 95 % confidence intervals [CIs]: 2.21 to 3.16), poorer mental intactness (β = -0.317 [-0.508 to -0.125]), and worse global cognition (-0.437 [-0.693 to -0.181]). Trend analyses showed a dose-response association between accumulated ACE_S and subsequent depression and cognitive impairment. No modifications of those associations by age, sex, educational level, or family's financial status during childhood were observed.

LIMITATIONS

Self-reported measures could favour recall bias.

CONCLUSION

Our study suggests that ACE_S increase the risk of subsequent depression and cognitive impairment in Chinese adults regardless of sociodemographic characteristics. These findings provide important implications for mitigating the adverse effects of early-life stress and promoting health in adulthood.

Area-Level Infant Mortality Exposure in Early Life and Alzheimer's Disease Mortality: Examining Variation Based on Age, Sex, and Place of Birth

BACKGROUND

Growing evidence suggests that critical periods in early life may contribute to one's risk of Alzheimer's disease and related dementias (ADRD) in later life. In this paper we explore the role that exposure to infant mortality plays in later life ADRD.

OBJECTIVE

To determine if exposure to early life infant mortality is associated with later mortality from ADRD. Also, we explore how these associations differ by sex and age group, along with the role of state of birth and competing risks of death.

METHODS

We use a sample of over 400,000 individuals aged 50 and above with the NIH-AARP Diet and Health Study with mortality follow-up, allowing us to examine how early life infant mortality rates along with other risk factors play in one's individual mortality risk.

RESULTS

We show that infant mortality rates are associated with death from ADRD among those under 65 years of age, but not those over 65 at baseline interview. Moreover, when factoring in competing risks of death, the associations are relatively unchanged.

CONCLUSION

These results suggest that those exposed to worse adverse conditions during critical periods increase their likelihood of death from ADRD earlier than average, due to that exposure increasing their susceptibility to develop illness later on in life.

Childhood socio-economic circumstances and dementia: prospective register-based cohort study of adulthood socio-economic and cardiovascular health mediators

Background

This study analysed the association between childhood socio-economic circumstances and the risk of dementia, and investigated the mediating role of potentially modifiable risk factors including adulthood socio-economic position and cardiovascular health.

Methods

We used a 10% sample of the 1950 Finnish population census linked with subsequent population and health registers (n = 95 381). Information of socio-economic characteristics, family structure and housing conditions at the age of 0–15 years was obtained from the 1950 census. We identified cohort members who developed dementia in 2000–2018 using national hospital, medication and death registers. Discrete time survival analysis using logistic regression and mediation analysis applying the Karlson–Holm–Breen (KHB) method were employed.

Results

An excess risk of dementia was observed for household crowding [odds ratio (OR) = 1.10; 95% CI 1.02–1.18 for 3 to &lt;4 persons per heated room; OR = 1.19; 95% CI 1.11–1.27 for ≥4 persons], single-father family (OR = 1.27; 95% CI 1.07–1.51) and eastern and northern region of residence (OR = 1.19; 95% CI 1.10–1.28). The effects of single-father family and region of residence were mostly direct with adulthood characteristics mediating 14% and 29% of the total effect, respectively. The largest indirect effect was observed for household crowding mediated through adulthood socio-economic position (47–65%).

Conclusions

The study shows that childhood socio-economic circumstances are associated with dementia, and that the underlying mechanisms only partly relate to adulthood socio-economic position and cardiovascular health. Socio-economic and health interventions targeted at families with children may carry long-term benefits by contributing to a lower dementia risk in later life.

Racial and Ethnic Differences in Amyloid PET Positivity in Individuals With Mild Cognitive Impairment or Dementia: A Secondary Analysis of the Imaging Dementia-Evidence for Amyloid Scanning (IDEAS) Cohort Study

Importance

Racial and ethnic groups with higher rates of clinical Alzheimer disease (AD) are underrepresented in studies of AD biomarkers, including amyloid positron emission tomography (PET).

Objective

To compare amyloid PET positivity among a diverse cohort of individuals with mild cognitive impairment (MCI) or dementia.

Design, Setting, and Participants

Secondary analysis of the Imaging Dementia-Evidence for Amyloid Scanning (IDEAS), a single-arm multisite cohort study of Medicare beneficiaries who met appropriate-use criteria for amyloid PET imaging between February 2016 and September 2017 with follow-up through January 2018. Data were analyzed between April 2020 and January 2022. This study used 2 approaches: the McNemar test to compare amyloid PET positivity proportions between matched racial and ethnic groups and multivariable logistic regression to assess the odds of having a positive amyloid PET scan. IDEAS enrolled participants at 595 US dementia specialist practices. A total of 21 949 were enrolled and 4842 (22%) were excluded from the present analysis due to protocol violations, not receiving an amyloid PET scan, not having a positive or negative scan, or because of small numbers in some subgroups.

Exposures

In the IDEAS study, participants underwent a single amyloid PET scan.

Main Outcomes and Measures

The main outcomes were amyloid PET positivity proportions and odds.

Results

Data from 17 107 individuals (321 Asian, 635 Black, 829 Hispanic, and 15 322 White) with MCI or dementia and amyloid PET were analyzed between April 2020 and January 2022. The median (range) age of participants was 75 (65-105) years; 8769 participants (51.3%) were female and 8338 (48.7%) were male. In the optimal 1:1 matching analysis (n = 3154), White participants had a greater proportion of positive amyloid PET scans compared with Asian participants (181 of 313; 57.8%; 95% CI, 52.3-63.2 vs 142 of 313; 45.4%; 95% CI, 39.9-50.9, respectively; P = .001) and Hispanic participants (482 of 780; 61.8%; 95% CI, 58.3-65.1 vs 425 of 780; 54.5%; 95% CI, 51.0-58.0, respectively; P = .003) but not Black participants (359 of 615; 58.4%; 95% CI, 54.4-62.2 vs 333 of 615; 54.1%; 95% CI, 50.2-58.0, respectively; P = .13). In the adjusted model, the odds of having a positive amyloid PET scan were lower for Asian participants (odds ratio [OR], 0.47; 95% CI, 0.37-0.59; P < .001), Black participants (OR, 0.71; 95% CI, 0.60-0.84; P < .001), and Hispanic participants (OR, 0.68; 95% CI, 0.59-0.79; P < .001) compared with White participants.

Conclusions and Relevance

Racial and ethnic differences found in amyloid PET positivity among individuals with MCI and dementia in this study may indicate differences in underlying etiology of cognitive impairment and guide future treatment and prevention approaches.

Global, regional, and national trends of dementia incidence and risk factors, 1990-2019: A Global Burden of Disease study

BACKGROUND

An ample literature documents the growing prevalence of dementia and associated costs. Less attention has been paid to decreased dementia incidence in some countries.

METHODS

We analyzed trends in age-standardized dementia, stroke, and ischemic heart disease (the triple threat) incidence rates and population attributable fraction of death and disability attributable to 12 risk factors in 204 countries and territories and 51 regions using Global Burden of Disease 2019 data.

RESULTS

During 1990 to 2019, dementia incidence declined in 71 countries; 18 showed statistically significant declines, ranging from -12.1% (95% uncertainty intervals -16.9 to -6.8) to -2.4% (-4.6 to -0.5). During 2010 to 2019, 16 countries showed non-significant declines. Globally, the burden of the triple threat attributable to air pollution, dietary risks, non-optimal temperature, lead exposure, and tobacco use decreased from 1990 to 2019.

CONCLUSION

The declining incidence of dementia in some countries, despite growing prevalence, is encouraging and urges further investigation.

The health status: the ignored risk factor in dementia incidence. NEDICES cohort

BACKGROUND

The causes of the dementia decrease in affluent countries are not well known but health amelioration could probably play a major role. Nevertheless, although many vascular and systemic disorders in adult life are well-known risk factors (RF) for dementia and Alzheimer disease (AD), health status is rarely considered as a single RF.

AIM

To analyse whether the health status and the self-perceived health (SPH) could be RF for dementia and AD and to discuss its biological basis.

METHODS

We analysed different objective health measures and SPH as RF for dementia and AD incidence in 4569 participants of the NEDICES cohort by means of Cox-regression models. The mean follow-up period was 3.2 (range: 0.03-6.6) years.

RESULTS

Ageing, low education, history of stroke, and "poor" SPH were the main RF for dementia and AD incidence, whereas physical activity was protective. "Poor" SPH had a hazard ratio = 1.66 (95% CI 1.17-2.46; p = 0.012) after controlling for different confounders.

DISCUSSION

According to data from NEDICES cohort, SPH is a better predictor of dementia and AD than other more objective health status proxies. SPH should be considered a holistic and biologically rooted indicator of health status, which can predict future development of dementia and AD in older adults.

CONCLUSIONS

Our data indicate that it is worthwhile to include the SPH status as a RF in the studies of dementia and AD incidence and to explore the effect of its improvement in the evolution of this incidence.

Integrating DNA Methylation Measures of Biological Aging into Social Determinants of Health Research

PURPOSE OF REVIEW

Acceleration of biological processes of aging is hypothesized to drive excess morbidity and mortality in socially disadvantaged populations. DNA methylation measures of biological aging provide tools for testing this hypothesis.

RECENT FINDINGS

Next-generation DNA methylation measures of biological aging developed to predict mortality risk and physiological decline are more predictive of morbidity and mortality than the original epigenetic clocks developed to predict chronological age. These new measures show consistent evidence of more advanced and faster biological aging in people exposed to socioeconomic disadvantage and may be able to record the emergence of socially determined health inequalities as early as childhood. Next-generation DNA methylation measures of biological aging also indicate race/ethnic disparities in biological aging. More research is needed on these measures in samples of non-Western and non-White populations. New DNA methylation measures of biological aging open opportunities for refining inference about the causes of social disparities in health and devising policies to eliminate them. Further refining measures of biological aging by including more diversity in samples used for measurement development is a critical priority for the field.

2022 Alzheimer's disease facts and figures

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

Birth Cohorts and Cognitive Reserve Influence Cognitive Performances in Older Adults

BACKGROUND

Evidence suggests birth cohort differences in cognitive performance of older adults. Proxies of cognitive reserve (CR), such as educational attainment and occupational complexity, could also partly account for these differences as they are influenced by the sociocultural environment of the birth cohorts.

OBJECTIVE

To predict cognitive performance using birth cohorts and CR and examine the moderating influence of CR on cognitive performance and structural brain health association.

METHODS

Using ADNI data (n = 1628), four birth cohorts were defined (1915-1928; 1929-1938; 1939-1945; 1946-1964). CR proxies were education, occupational complexity, and verbal IQ. We predicted baseline cognitive performances (verbal episodic memory; language and semantic memory; attention capacities; executive functions) using multiple linear regressions with CR, birth cohorts, age, structural brain health (total brain volume; total white matter hyperintensities volume) and vascular risk factors burden as predictors. Sex and CR interactions were also explored.

RESULTS

Recent birth cohorts, higher CR, and healthier brain structures predicted better performance in verbal episodic memory, language and semantic memory, and attention capacities, with large effect sizes. Better performance in executive functions was predicted by a higher CR and a larger total brain volume, with a small effect size. With equal score of CR, women outperformed men in verbal episodic memory and language and semantic memory in all cohorts. Higher level of CR predicted better performance in verbal episodic memory, only when total brain volume was lower.

CONCLUSION

Cohort differences in cognitive performance favor more recent birth cohorts and suggests that this association may be partly explained by proxies of CR.

Brain Health Services: organization, structure, and challenges for implementation. A user manual for Brain Health Services-part 1 of 6

Dementia has a devastating impact on the quality of life of patients and families and comes with a huge cost to society. Dementia prevention is considered a public health priority by the World Health Organization. Delaying the onset of dementia by treating associated risk factors will bring huge individual and societal benefit. Empirical evidence suggests that, in higher-income countries, dementia incidence is decreasing as a result of healthier lifestyles. This observation supports the notion that preventing dementia is possible and that a certain degree of prevention is already in action. Further reduction of dementia incidence through deliberate prevention plans is needed to counteract its growing prevalence due to increasing life expectancy.An increasing number of individuals with normal cognitive performance seek help in the current memory clinics asking an evaluation of their dementia risk, preventive interventions, or interventions to ameliorate their cognitive performance. Consistent evidence suggests that some of these individuals are indeed at increased risk of dementia. This new health demand asks for a shift of target population, from patients with cognitive impairment to worried but cognitively unimpaired individuals. However, current memory clinics do not have the programs and protocols in place to deal with this new population.We envision the development of new services, henceforth called Brain Health Services, devoted to respond to demands from cognitively unimpaired individuals concerned about their risk of dementia. The missions of Brain Health Services will be (i) dementia risk profiling, (ii) dementia risk communication, (iii) dementia risk reduction, and (iv) cognitive enhancement. In this paper, we present the organizational and structural challenges associated with the set-up of Brain Health Services.

Association of Military Employment With Late-Life Cognitive Decline and Dementia: A Population-Based Prospective Cohort Study

INTRODUCTION

As the number of U.S. veterans over age 65 has increased, interest in whether military service affects late-life health outcomes has grown. Whether military employment is associated with increased risk of cognitive decline and dementia remains unclear.

MATERIALS AND METHODS

We used data from 4,370 participants of the longitudinal Adult Changes in Thought (ACT) cohort study, enrolled at age 65 or older, to examine whether military employment was associated with greater cognitive decline or higher risk of incident dementia in late life. We classified persons as having military employment if their first or second-longest occupation was with the military. Cognitive status was assessed at each biennial Adult Changes in Thought study visit using the Cognitive Abilities Screening Instrument, scored using item response theory (CASI-IRT). Participants meeting screening criteria were referred for dementia ascertainment involving clinical examination and additional cognitive testing. Primary analyses were adjusted for sociodemographic characteristics and APOE genotype. Secondary analyses additionally adjusted for indicators of early-life socioeconomic status and considered effect modification by age, gender, and prior traumatic brain injury with loss of consciousness TBI with LOC.

RESULTS

Overall, 6% of participants had military employment; of these, 76% were males. Military employment was not significantly associated with cognitive change (difference in modeled 10-year cognitive change in CASI-IRT scores in SD units (95% confidence interval [CI]): -0.042 (-0.19, 0.11), risk of dementia (hazard ratio [HR] [95% CI]: 0.92 [0.71, 1.18]), or risk of Alzheimer's disease dementia (HR [95% CI]: 0.93 [0.70, 1.23]). These results were robust to additional adjustment and sensitivity analyses. There was no evidence of effect modification by age, gender, or traumatic brain injury with loss of consciousness.

CONCLUSIONS

Among members of the Adult Changes in Thought cohort, military employment was not associated with increased risk of cognitive decline or dementia. Nevertheless, military veterans face the same high risks for cognitive decline and dementia as other aging adults.

The plasticity of late-onset dementia: A nationwide cohort study in Denmark

INTRODUCTION

The determinants of the secular decline in the incidence of dementia are not clear. The aim of this study was to investigate the influences of four factors-education, wealth, cerebrovascular health, and general health-on the secular decline.

METHODS

A cohort study was conducted of all individuals aged ≥65 years in Denmark from 2005 through 2018 (N = 1,757,168). Annual incidence rates of dementia and population attributable risks of the four factors were calculated and birth cohort trends were examined.

RESULTS

The incidence of dementia declined by 22.5% in men and 34.2% in women from 2005 through 2018. Population attributable risks of lower education, lower wealth, and stroke likewise declined. Independent of these improvements, the incidence of dementia fell across successive birth cohorts.

DISCUSSION

Most of the observed plasticity in late-onset dementia is associated with a risk decline across successive birth cohorts that is independent of improvements in traditional risk factors.

Measurement Equivalence between the Original and Estimated Mini-Mental State Examination in People with Dementia

Background: The Cognitive Abilities Screening Instrument (CASI) is increasingly used to assess general cognitive function in people with dementia. The Mini-Mental State Examination (MMSE) score can be converted from the CASI (i.e., the estimated MMSE). Recognizing that measurement equivalence is critical to meaningfully representing one with the other, we aimed to determine whether the estimated MMSE score obtained from the CASI was equivalent to the original MMSE in people with dementia. Methods: We obtained 110 data points for the MMSE and CASI scores in people with dementia. The intraclass correlation coefficient (ICC), Pearson’s r, percent of standard error of measurement (SEM%), paired t-test, and effect size (Cohen’s d) were used to investigate the equivalence. Results: To examine the equivalence between the original and estimated MMSE score, the ICC and Pearson’s r of the total score and six domains were 0.62–0.95 and 0.62–0.96, respectively. The SEM% of the total score and six domains were 0.6–8.9%. The paired t-test results showed a significant difference (p < 0.05) between the total score and the three domains. The Cohen’s d of the total score and six domains were 0.06–0.27. Conclusions: The estimated MMSE score was found to have moderate to excellent equivalence to the original MMSE score. The three domains (i.e., registration, attention and calculation, and visual-constructional ability) with moderate equivalence should be used cautiously to interchange with the original MMSE in people with dementia.

Childhood Socioeconomic Status Does Not Predict Late-Life Cognitive Decline in the 1936 Lothian Birth Cohort

This study examined childhood socioeconomic status (SES) as a predictor of later life cognitive decline. Data came from 519 participants in the Lothian Birth Cohort 1936 (LBC1936) study. SES measures at 11 years of age included parental educational attainment, father's occupational status, household characteristics and a composite measure of global childhood SES (i.e., a total of low SES childhood indicators). Cognitive abilities were assessed by the Mini-Mental State Exam at ages 69.8, 72.8 and 76.7 years. Most indicators of low childhood SES (i.e., father manual worker, less than secondary school father education, household overcrowding, exterior located toilet, and global childhood SES) did not predict cognitive decline between the ages of 69.8 and 76.7. Participants with less educated mothers showed an increase in cognitive decline (β = -0.132, p = 0.048, and CI = -0.80, -0.00). The relationship between maternal educational attainment and cognitive decline became non-significant when controlling for adult SES (i.e., participant educational attainment and occupation). Adult SES did not mediate the latter relationship. This study provides new evidence that childhood SES alone is not strongly associated with cognitive decline. New knowledge is critical to improving population health by identifying life span stages in which interventions might be effective in preventing cognitive decline.

What Happens to the Worried Well? Follow-Up of Subjective Cognitive Impairment

BACKGROUND

Increasing concern around perceived neurocognitive decline is increasing the number of referrals to specialists and anxiety for patients. We aimed to explore the likelihood of the "worried well" experiencing neurocognitive decline and developing a neurological diagnosis.

METHODS

A total of 166 "worried well" patients who attended the Rural and Remote Memory Clinic (RRMC) between 2004 and 2019 were included in this study. Demographic, health, social, and behavioral factors were measured at the initial visit. Mini-Mental State Examination (MMSE), Center for Epidemiologic Studies Depression Scale (CESD), and Functional Activities Questionnaire (FAQ) scores were measured and compared at initial assessment and at 1-year follow-up. MMSE scores over time were assessed with a mean follow-up of 2.95 years (SD 2.87).

RESULTS

No statistically significant difference was seen in MMSE, CESD, or FAQ scores when comparing clinic day to 1-year follow-up, and no consistent pattern of MMSE score over time was seen. Of the 166 patients with subjective cognitive impairment (SCI) on initial assessment, 5 were diagnosed with Alzheimer's disease (AD) at 8.5, 3.5, 5, 3, and 1.75 years; 2 were diagnosed with MCI at 1 and 2 years; 1 was diagnosed with vascular cognitive impairment at 5 years; and 1 was diagnosed with frontotemporal dementia (FTD) at 0.5 years.

CONCLUSION

The likelihood of a patient with SCI developing a neurological diagnosis is reassuringly low (9/166), but not irrelevant. This, along with the benefits of early diagnosis and treatment for dementia, leads us to believe that patients with SCI should still be seen in follow-up at least at the 1-year mark.