Secular Trends in the Incidence of Dementia in a Multi-Ethnic Community

A Polysocial Approach in Exploring Racial and Ethnic Differences in Dementia and Cognitive Decline Among U.S. Older Adults: Health and Retirement Study

Background and Objectives

The racial or ethnic disparity in the burden of dementia exists among older adults in the United States, whereas gaps remain in understanding the synergic effect of multiple social determinants of health on diminishing this disparity. We aim to build a polysocial score for dementia and investigate the racial or ethnic difference in dementia risk among older persons with different polysocial score categories.

Research Design and Methods

In this prospective cohort study, we utilized longitudinal data from the Health and Retirement Study in the United States recruiting 6 945 participants aged ≥65 years who had data on 24 social determinants of health in 2006/2008. The dementia status of participants was measured by a modified version of the Telephone Interview of Cognitive Status. The stepwise Cox regression was applied to select social determinants of health associated with incident dementia to construct a polysocial score. The multivariable Poisson model and linear mixed model were utilized to investigate the associations between polysocial score and incident dementia and cognitive decline, respectively.

Results

Eight social determinants of health were used to build the polysocial score. Non-Hispanic Black older participants had a higher incidence rate (incidence rate difference [IRD] = 22.7; 95% confident interval [95% CI] = 12.7-32.8) than non-Hispanic White older adults in the low polysocial score, while this difference was substantially attenuated in the high polysocial score category (IRD = 0.5; 95% CI = -6.4 to -7.5). The cognitive decline of non-Hispanic older Black adults with high polysocial score was 84.6% slower (averaged cognitive decline: non-Hispanic White: -2.4 [95% CI = -2.5 to -2.3] vs non-Hispanic Black: -1.3 [95% CI = -1.9 to -0.8]) than that of non-Hispanic older White persons.

Discussion and Implications

These findings may help comprehensively understand and address racial and ethnic disparities in dementia risk and may be integrated into existing dementia prevention programs to provide targeted interventions for community-dwelling older adults with differentiated social disadvantages.

Charting Alzheimer's Disease and Dementia: Epidemiological Insights, Risk Factors and Prevention Pathways

Alzheimer's disease (AD), the most common cause of dementia, is a complex and multifactorial condition without cure at present. The latest treatments, based on anti-amyloid monoclonal antibodies, have only a modest effect in reducing the progression of cognitive decline in AD, whereas the possibility of preventing AD has become a crucial area of research. In fact, recent studies have observed a decrease in dementia incidence in developed regions such as the US and Europe. However, these trends have not been mirrored in non-Western countries (Japan or China), and the contributing factors of this reduction remain unclear. The Lancet Commission has delineated a constrained classification of 12 risk factors across different life stages. Nevertheless, the scientific literature has pointed to over 200 factors-including sociodemographic, medical, psychological, and sociocultural conditions-related to the development of dementia/AD. This narrative review aims to synthesize the risk/protective factors of dementia/AD. Essentially, we found that risk/protective factors vary between individuals and populations, complicating the creation of a unified prevention strategy. Moreover, dementia/AD explanatory mechanisms involve a diverse array of genetic and environmental factors that interact from the early stages of life. In the future, studies across different population-based cohorts are essential to validate risk/protective factors of dementia. This evidence would help develop public health policies to decrease the incidence of dementia.

Changes in prevalence and incidence of dementia and risk factors for dementia: an analysis from cohort studies

BACKGROUND

Some cohort studies have reported a decline in dementia prevalence and incidence over time, although these findings have not been consistent across studies. We reviewed evidence on changes in dementia prevalence and incidence over time using published population-based cohort studies that had used consistent methods with each wave and aimed to quantify associated changes in risk factors over time using population attributable fractions (PAFs).

METHODS

We searched for systematic reviews of cohort studies examining changes in dementia prevalence or incidence over time. We searched PubMed for publications from database inception up to Jan 12, 2023, using the search terms "systematic review" AND "dementia" AND ("prevalence" OR "incidence"), with no language restrictions. We repeated this search on March 28, 2024. From eligible systematic reviews, we searched the references and selected peer-reviewed publications about cohort studies where dementia prevalence or incidence was measured in the same geographical location, at a minimum of two timepoints, and that reported age-standardised prevalence or incidence of dementia. Additionally, data had to be from population-based samples, in which participants' cognitive status was assessed and where validated criteria were used to diagnose dementia. We extracted summary-level data from each paper about dementia risk factors, contacting authors when such data were not available in the published paper, and calculated PAFs for each risk factor at all available timepoints. Where possible, we linked changes in dementia prevalence or incidence with changes in the prevalence of risk factors.

FINDINGS

We identified 1925 records in our initial search, of which five eligible systematic reviews were identified. Within these systematic reviews, we identified 71 potentially eligible primary papers, of which 27 were included in our analysis. 13 (48%) of 27 primary papers reported change in prevalence of dementia, ten (37%) reported change in incidence of dementia, and four (15%) reported change in both incidence and prevalence of dementia. Studies reporting change in dementia incidence over time in Europe (n=5) and the USA (n=5) consistently reported a declining incidence in dementia. One study from Japan reported an increase in dementia prevalence and incidence and a stable incidence was reported in one study from Nigeria. Overall, across studies, the PAFs for less education or smoking, or both, generally declined over time, whereas PAFs for obesity, hypertension, and diabetes generally increased. The decrease in PAFs for less education and smoking was associated with a decline in the incidence of dementia in the Framingham study (Framingham, MA, USA, 1997-2013), the only study with sufficient data to allow analysis.

INTERPRETATION

Our findings suggest that lifestyle interventions such as compulsory education and reducing rates of smoking through country-level policy changes could be associated with an observed reduction, and therefore future reduction, in the incidence of dementia. More studies are needed in low-income and middle-income countries, where the burden of dementia is highest, and continues to increase.

FUNDING

National Institute for Health and Care Research Three Schools' Dementia Research Programme.

Periodontitis and brain magnetic resonance imaging markers of Alzheimer's disease and cognitive aging

INTRODUCTION

We examined the association of clinical, microbiological, and host response features of periodontitis with MRI markers of atrophy/cerebrovascular disease in the Washington Heights Inwood Columbia Aging Project (WHICAP) Ancillary Study of Oral Health.

METHODS

We analyzed 468 participants with clinical periodontal data, microbial plaque and serum samples, and brain MRIs. We tested the association of periodontitis features with MRI features, after adjusting for multiple risk factors for Alzheimer's disease/Alzheimer's disease-related dementia (AD/ADRD).

RESULTS

In fully adjusted models, having more teeth was associated with lower odds for infarcts, lower white matter hyperintensity (WMH) volume, higher entorhinal cortex volume, and higher cortical thickness. Higher extent of periodontitis was associated with lower entorhinal cortex volume and lower cortical thickness. Differential associations emerged between colonization by specific bacteria/serum antibacterial IgG responses and MRI outcomes.

DISCUSSION

In an elderly cohort, clinical, microbiological, and serological features of periodontitis were associated with MRI findings related to ADRD risk. Further investigation of causal associations is warranted.

Controversial Past, Splendid Present, Unpredictable Future: A Brief Review of Alzheimer Disease History

Background: The concept of Alzheimer disease (AD)-since its histological discovery by Alzheimer to the present day-has undergone substantial modifications. Methods: We conducted a classical narrative review of this field with a bibliography selection (giving preference to Medline best match). Results: The following subjects are reviewed and discussed: Alzheimer's discovery, Kraepelin's creation of a new disease that was a rare condition until the 1970's, the growing interest and investment in AD as a major killer in a society with a large elderly population in the second half of the 20th century, the consolidation of the AD clinicopathological model, and the modern AD nosology based on the dominant amyloid hypothesis among many others. In the 21st century, the development of AD biomarkers has supported a novel biological definition of AD, although the proposed therapies have failed to cure this disease. The incidence of dementia/AD has shown a decrease in affluent countries (possibly due to control of risk factors), and mixed dementia has been established as the most frequent etiology in the oldest old. Conclusions: The current concept of AD lacks unanimity. Many hypotheses attempt to explain its complex physiopathology entwined with aging, and the dominant amyloid cascade has yielded poor therapeutic results. The reduction in the incidence of dementia/AD appears promising but it should be confirmed in the future. A reevaluation of the AD concept is also necessary.

Dementia literacy of racially minoritized people in a Chinese society: a qualitative study among South Asian migrants in Hong Kong

OBJECTIVES

Research on dementia literacy in Chinese societies is still emerging, and this is especially the case among racially minoritized groups. The present study explored the knowledge, causal beliefs, and help-seeking behaviors of South Asian migrants in Hong Kong about dementia. It also investigated existing community barriers related to dementia knowledge and help-seeking.

DESIGN

We conducted a qualitative study from a purposive sample of 38 older people and family caregivers from India, Pakistan, and Nepal who lived in Hong Kong. Focus groups and individual in-depth interviews were used to gather information, while thematic analysis was employed to analyze the data.

RESULTS

Five main themes were identified: normalization with stigmatization of dementia; spiritual and psychosocial attributions of dementia; familial responsibility despite potential caregiving burden; uncertainties versus openness to professional care; and barriers and opportunities in dementia literacy. Ethnic minorities recognized dementia as a disease of normal aging or a mental disorder. They also perceived spiritual and psychosocial factors as their main causes. While participants recognized the potential burden of dementia caregiving, families were their first point of help-seeking, as many of them expressed contrasting feelings of confidence or doubt toward professional services. Utilization of health education strategies, together with collaboration with community leaders, could address the barriers to dementia literacy.

CONCLUSIONS

This is the first study to explore how ethnic minorities in Asia perceive dementia and its related help-seeking behaviors in their communities. South Asian migrants in Hong Kong have a limited understanding of dementia and may experience delays in obtaining relevant community services. While culture influenced their knowledge, health education may address their misperceptions and help-seeking behaviors toward dementia. Culture- and language-specific programs could also improve dementia knowledge and health service access.

Heart Disease and Stroke Statistics-2023 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2023 Statistical Update is the product of a full year's worth of effort in 2022 by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. The American Heart Association strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional COVID-19 (coronavirus disease 2019) publications, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Racial/Ethnic Disparities in Misidentification of Dementia in Medicare Claims: Results from the Washington Heights-Inwood Columbia Aging Project

BACKGROUND

Misidentification of dementia in Medicare claims is quite common.

OBJECTIVE

We examined potential race/ethnic disparities in misidentification of dementia in Medicare claims in a diverse cohort of older adults who underwent careful clinical assessment.

METHODS

Participants were enrolled in the Washington Heights-Inwood Columbia Aging Project (WHICAP), a multiethnic, population-based, prospective study of cognitive aging in which dementia status was assessed using a rigorous clinical protocol. ICD-9-CM and ICD-10-CM diagnosis codes in all available Medicare claims (1999-2019) were compared to clinical dementia diagnosis and categorized into three mutually exclusive groups: 1) congruent-, 2) over-, and 3) under- identification during the study period. Multinomial logistic regression model was used to examine the relationship between race (White, African American/Black, other) and ethnicity (Hispanic/Latinx, non-Hispanic/Latinx) and congruency of dementia identification after controlling for clinical (cognition, function, comorbidities) and demographic characteristics (age, sex, education), and inpatient and outpatient utilization.

RESULTS

Across all person-years, 88.4% had congruent identification of dementia compared to clinical diagnosis, in 4.1% of the times participants were over-identified with dementia, and 7.5% of the times the participants were under-identified. Rates of misidentification was higher in minority participants than in White, non-Hispanic participants. Multivariable estimation results showed that the probability of over-identification with dementia was 2.2% higher for African American/Black than White (p = 0.05) and 2.7% higher for Hispanic participants than non-Hispanics (p = 0.03) participants. Differences in under-identification by race/ethnicity were not statistically significant.

CONCLUSIONS

African American/Black and Hispanic participants were more likely over-identified with dementia in Medicare claims.

Association of Race and Income with Incident Diagnosis of Alzheimer's Disease and Related Dementias among Black and White Older Adults

To investigate how differences in income and education levels may contribute to disparities in incidence of Alzheimer's disease and related dementia (ADRD), we compared ADRD incidence in traditional Medicare claims for 11,132 Black and 7703 White participants aged 65 and over from a predominantly low-income cohort. We examined whether the relationship between ADRD incidence and race varied by income or education. Based on 2015 incident ADRD diagnoses, Black and White participants had unadjusted incidence rates of 26.5 and 23.2 cases per 1000 person-years, respectively (rate ratio 1.14, 95% CI 1.05-1.25). In multivariable Cox proportional hazard models, the relationship between race and incident ADRD diagnosis did not vary by education level (p-interaction = 0.748) but was modified by income level (p-interaction = 0.007), with higher ADRD incidence among Black participants observed only among higher income groups. These results highlight the importance of understanding how race and economic factors influence ADRD incidence and diagnosis rates.

Including ethnic minorities in dementia research: Recommendations from a scoping review

Introduction

Ethnicity influences dementia etiology, prognosis, and treatment, while culture shapes help-seeking and care. Despite increasing population diversity in high-income settlement countries, ethnic minorities remain underrepresented in dementia research. We investigated approaches to enhance the recruitment, and consistent collection and analysis of variables relevant to, ethnic minorities in dementia studies to make recommendations for consistent practice in dementia research.

Methods

We did a scoping review, searching Embase, PsycINFO, Medline, CENTRAL, and CINAHL between January 1, 2010 and January 7, 2020. Dementia clinical and cohort studies that actively recruited ethnic minorities in high-income countries were included. A steering group of experts developed criteria through which high-quality studies were identified.

Results

Sixty-six articles were retrieved (51 observational; 15 experimental). Use of interpreters and translators (n = 17) was the most common method to facilitate participant recruitment. Race and ethnicity (n = 59) were the most common variables collected, followed by information on native language (n = 14), country of birth (n = 9), and length of time in country of settlement (n = 8). Thirty-three studies translated or used a culturally validated instrument. Twenty-three articles conducted subgroup analyses based on ethnicity. Six high-quality studies facilitated inclusion through community engagement, collected information on multiple aspects of ethnic diversity, and adjusted/substratified to analyze the impact of ethnicity on dementia.

Discussion

We make recommendations for consistent recruitment, collection, and reporting of variables relating to ethnic and cultural diversity in dementia research.

Heart Disease and Stroke Statistics-2022 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2022 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population and an enhanced focus on social determinants of health, adverse pregnancy outcomes, vascular contributions to brain health, and the global burden of cardiovascular disease and healthy life expectancy.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Vascular Cognitive Impairment (VCI)

Vascular cognitive impairment (VCI) is predominately caused by vascular risk factors and cerebrovascular disease. VCI includes a broad spectrum of cognitive disorders, from mild cognitive impairment to vascular dementia caused by ischemic or hemorrhagic stroke, and vascular factors alone or in a combination with neurodegeneration including Alzheimer's disease (AD) and AD-related dementia. VCI accounts for at least 20-40% of all dementia diagnosis. Growing evidence indicates that cerebrovascular pathology is the most important contributor to dementia, with additive or synergistic interactions with neurodegenerative pathology. The most common underlying mechanism of VCI is chronic age-related dysregulation of CBF, although other factors such as inflammation and cardiovascular dysfunction play a role. Vascular risk factors are prevalent in VCI and if measured in midlife they predict cognitive impairment and dementia in later life. Particularly, hypertension, high cholesterol, diabetes, and smoking at midlife are each associated with a 20 to 40% increased risk of dementia. Control of these risk factors including multimodality strategies with an inclusion of lifestyle modification is the most promising strategy for treatment and prevention of VCI. In this review, we present recent developments in age-related VCI, its mechanisms, diagnostic criteria, neuroimaging correlates, vascular risk determinants, and current intervention strategies for prevention and treatment of VCI. We have also summarized the most recent and relevant literature in the field of VCI.

A Decade of Decline in Serious Cognitive Problems Among Older Americans: A Population-Based Study of 5.4 Million Respondents

BACKGROUND

Numerous studies suggest the prevalence of dementia has decreased over the past several decades in Western countries. Less is known about whether these trends differ by gender or age cohort, and if generational differences in educational attainment explain these trajectories.

OBJECTIVE

1) To detect temporal trends in the age-sex-race adjusted prevalence of serious cognitive problems among Americans aged 65+; 2) To establish if these temporal trends differ by gender and age cohort; 3) To examine if these temporal trends are attenuated by generational differences in educational attainment.

METHODS

Secondary analysis of 10 years of annual nationally representative data from the American Community Survey with 5.4 million community-dwelling and institutionalized older adults aged 65+. The question on serious cognitive problems was, "Because of a physical, mental, or emotional condition, does this person have serious difficulty concentrating, remembering, or making decisions?"

RESULTS

The prevalence of serious cognitive problems in the US population aged 65 and older declined from 12.2% to 10.0% between 2008 and 2017. Had the prevalence remained at the 2008 levels, there would have been an additional 1.13 million older Americans with serious cognitive problems in 2017. The decline in memory problems across the decade was higher for women (23%) than for men (13%). Adjusting for education substantially attenuated the decline.

CONCLUSION

Between 2008 and 2017, the prevalence of serious cognitive impairment among older Americans declined significantly, although these declines were partially attributable to generational differences in educational attainment.

Production of Inflected Novel Words in Older Adults With and Without Dementia

While cognitive changes in aging and neurodegenerative disease have been widely studied, language changes in these populations are less well understood. Inflecting novel words in a language with complex inflectional paradigms provides a good opportunity to observe how language processes change in normal and abnormal aging. Studies of language acquisition suggest that children inflect novel words based on their phonological similarity to real words they already know. It is unclear whether speakers continue to use the same strategy when encountering novel words throughout the lifespan or whether adult speakers apply symbolic rules. We administered a simple speech elicitation task involving Finnish-conforming pseudo-words and real Finnish words to healthy older adults, individuals with mild cognitive impairment, and individuals with Alzheimer's disease (AD) to investigate inflectional choices in these groups and how linguistic variables and disease severity predict inflection patterns. Phonological resemblance of novel words to both a regular and an irregular inflectional type, as well as bigram frequency of the novel words, significantly influenced participants' inflectional choices for novel words among the healthy elderly group and people with AD. The results support theories of inflection by phonological analogy (single-route models) and contradict theories advocating for formal symbolic rules (dual-route models).

Trends in Relative Incidence and Prevalence of Dementia Across Non-Hispanic Black and White Individuals in the United States, 2000-2016

Importance

In the US, dementia risk is higher in non-Hispanic Black individuals than in non-Hispanic White individuals. To evaluate progress toward reducing such disparities, tracking secular trends in racial disparities in dementia prevalence is essential.

Objective

To examine whether relative racial disparities in dementia prevalence or incidence have changed in the US from 2000 to 2016.

Design, Settings, and Participants

The Health and Retirement Study (HRS) is a nationally representative study of adults 50 years or older. New participants are recruited every 6 years, and study visits occur biennially. Approximately 17 000 to 22 000 respondents have been surveyed at each wave since 2000, achieving response rates of 81% to 89%. Data for this cohort study were obtained from non-Hispanic White and non-Hispanic Black participants aged 70 years and older from the 2000 to 2016 waves. For analyses of secular trends in racial disparities in dementia prevalence, each HRS wave was considered separately (range of participants meeting eligibility criteria in each wave, 6322-7579). For analyses of secular trends in racial disparities in dementia incidence, 7 subcohorts were created (range of participants meeting eligibility criteria in each subcohort, 5322-5961) following up people without dementia for 4 years from subcohort baseline visits in 2000, 2002, 2004, 2006, 2008, 2010, and 2012. Data were analyzed from October 2019 to August 2020.

Exposures

Race based on self-response to closed-ended survey questions.

Main Outcomes and Measures

Dementia status was determined using 3 algorithms with similar sensitivity and specificity across non-Hispanic White and Black participants. Disparities were characterized using ratio measures.

Results

In this study, the mean age and percentage of male participants eligible for inclusion in analyses of racial disparities in dementia prevalence increased over time among non-Hispanic White participants (from 78.2 years and 40% in 2000 to 78.7 years and 44% in 2016) but remained steady in non-Hispanic Black participants during the same period (from 78.0 years and 37% in 2000 to 77.9 years and 38% in 2016). Prevalence ratios comparing Black and White participants ranged from approximately 1.5 to 1.9 across algorithms and years, whereas hazard ratios ranged from approximately 1.4 to 1.8. Although results suggest stable or declining dementia risk overall, there was no evidence suggesting change in relative racial disparities in dementia prevalence or incidence during follow-up.

Conclusions and Relevance

This study did not find evidence to suggest that the ratio of dementia risk across Black and White individuals changed in the US between 2000 and 2016. Additional efforts to identify and mitigate the source of these disparities is warranted.

Recent Consanguinity and Outbred Autozygosity Are Associated With Increased Risk of Late-Onset Alzheimer's Disease

Prior work in late-onset Alzheimer's disease (LOAD) has resulted in discrepant findings as to whether recent consanguinity and outbred autozygosity are associated with LOAD risk. In the current study, we tested the association between consanguinity and outbred autozygosity with LOAD in the largest such analysis to date, in which 20 LOAD GWAS datasets were retrieved through public databases. Our analyses were restricted to eight distinct ethnic groups: African-Caribbean, Ashkenazi-Jewish European, European-Caribbean, French-Canadian, Finnish European, North-Western European, South-Eastern European, and Yoruba African for a total of 21,492 unrelated subjects (11,196 LOAD and 10,296 controls). Recent consanguinity determination was performed using FSuite v1.0.3, according to subjects' ancestral background. The level of autozygosity in the outbred population was assessed by calculating inbreeding estimates based on the proportion (FROH) and the number (NROH) of runs of homozygosity (ROHs). We analyzed all eight ethnic groups using a fixed-effect meta-analysis, which showed a significant association of recent consanguinity with LOAD (N = 21,481; OR = 1.262, P = 3.6 × 10-4), independently of APOE ∗4 (N = 21,468, OR = 1.237, P = 0.002), and years of education (N = 9,257; OR = 1.274, P = 0.020). Autozygosity in the outbred population was also associated with an increased risk of LOAD, both for F ROH (N = 20,237; OR = 1.204, P = 0.030) and N ROH metrics (N = 20,237; OR = 1.019, P = 0.006), independently of APOE ∗4 [(F ROH, N = 20,225; OR = 1.222, P = 0.029) (N ROH, N = 20,225; OR = 1.019, P = 0.007)]. By leveraging the Alzheimer's Disease Sequencing Project (ADSP) whole-exome sequencing (WES) data, we determined that LOAD subjects do not show an enrichment of rare, risk-enhancing minor homozygote variants compared to the control population. A two-stage recessive GWAS using ADSP data from 201 consanguineous subjects in the discovery phase followed by validation in 10,469 subjects led to the identification of RPH3AL p.A303V (rs117190076) as a rare minor homozygote variant increasing the risk of LOAD [discovery: Genotype Relative Risk (GRR) = 46, P = 2.16 × 10-6; validation: GRR = 1.9, P = 8.0 × 10-4]. These results confirm that recent consanguinity and autozygosity in the outbred population increase risk for LOAD. Subsequent work, with increased samples sizes of consanguineous subjects, should accelerate the discovery of non-additive genetic effects in LOAD.

Dementia Incidence in the Elderly Population of Greece: Results From the HELIAD Study

OBJECTIVES

Recently a declining trend in dementia incidence rates has been reported in high-income countries. We investigated dementia incidence in a representative sample of the Greek population in the age group of 65 years and above.

METHODS

This research is part of the Hellenic Epidemiological Longitudinal Investigation of Aging and Diet (HELIAD). The incidence cohort consisted of 1072 participants who were reevaluated after a mean period of 3.09 years.

RESULTS

The incidence rate of dementia was 19.0 cases per 1000 person-years (age-standardized and sex-standardized incidence: 25.4/1000 person-years), of which 16.3 per 1000 person-years were attributable to Alzheimer disease. Each additional year of age increased dementia risk by 19.3% and each additional year of education decreased dementia risk by 12.1%. Apolipoprotein E (APOE)-ε4 homozygous participants were 18 times more likely to be diagnosed with dementia. A baseline diagnosis of mild cognitive decline (MCI) resulted in a risk for dementia increased by 3.7 times compared with the cognitively normal; in participants with MCI at baseline, APOE-ε4 carriage increased dementia risk by 4.5 times.

CONCLUSIONS

The incidence rate of dementia in people 65 years and above in Greece is generally consistent with recently published rates in Europe and North America. Advancing age, baseline MCI, and APOE-ε4 homozygosity are risk factors, while higher educational attainment seems protective.

Race/Ethnic Disparities in Mild Cognitive Impairment and Dementia: The Northern Manhattan Study

BACKGROUND

Variability in dementia rates across racial and ethnic groups has been estimated at 60%. Studies suggest disparities in Caribbean Hispanic and Black populations, but community-based data are limited.

OBJECTIVE

Estimate the prevalence of mild cognitive impairment (MCI) and dementia in the racially and ethnically diverse community-based Northern Manhattan Study cohort and examine sociodemographic, vascular risk factor, and brain imaging correlates.

METHODS

Cases of MCI and dementia were adjudicated by a team of neuropsychologists and neurologists and prevalence was estimated across race/ethnic groups. Ordinal proportional odds models were used to estimate race/ethnic differences in the prevalence of MCI or dementia adjusting for sociodemographic variables (model 1), model 1 plus potentially modifiable vascular risk factors (model 2), and model 1 plus structural imaging markers of brain integrity (model 3).

RESULTS

There were 989 participants with cognitive outcome determinations (mean age 69±9 years; 68% Hispanic, 16% Black, 14% White; 62% women; mean (±SD) follow-up five (±0.6) years). Hispanic and Black participants had greater likelihood of MCI (20%) and dementia (5%) than White participants accounting for age and education differences. Hispanic participants had greater odds of MCI or dementia than both White and Black participants adjusting for sociodemographic variables, vascular risk factors, and brain imaging factors. White matter hyperintensity burden was significantly associated with greater odds of MCI or dementia (OR = 1.3, 1.1 to 1.6), but there was no significant interaction by race/ethnicity.

CONCLUSION

In this diverse community-based cohort, cross-sectional data revealed significant race/ethnic disparities in the prevalence of MCI and dementia. Longer follow-up and incidence data are needed to further clarify these relationships.

Is milk and dairy intake a preventive factor for elderly cognition (dementia and Alzheimer's)? A quality review of cohort surveys

Milk and dairy (M&D) is a longstanding human food with widespread use. Many studies showed the preventive capacity of M&D in several human health disorders, but its utility in others is under discussion. Aging has been associated to elderly cognitive decline including dementia-Alzheimer syndrome (Dem-AD). The absence of a therapy to impede or postpone Dem-AD determines the need for its prevention, including nutritional factors. To evaluate the preventive capacity of M&D consumption in elderly Dem-AD we performed a systematic review in the main biomedical databases and information resources, but we present this study as a narrative review to discuss better the complexity of this subject. The elderly Dem-AD has a long pre-symptomatic period and the M&D intake has a widespread use. These determinants and the quality flaws of published studies impeach us to answer whether M&D consumption is preventive for Dem-AD. Moreover, two long Japanese cohorts suggest that M&D intake could prevent Dem-AD. Prospective cohorts beginning in midlife (or early life) could answer this question in the future.

Perspective on the "African American participation in Alzheimer disease research: Effective strategies" workshop, 2018

The Washington University School of Medicine Knight Alzheimer Disease Research Center's "African American Participation in Alzheimer Disease Research: Effective Strategies" Workshop convened to address a major limitation of the ongoing scientific progress regarding Alzheimer's disease and related dementias (ADRD): participants in most ADRD research programs overwhelmingly have been limited to non-Hispanic white persons, thus precluding knowledge as to how ADRD may be represented in non-white individuals. Factors that may contribute to successful recruitment and retention of African Americans into ADRD research were discussed and organized into actionable next steps as described within this report.

Dietary fatty acids and risk of Alzheimer's disease and related dementias: Observations from the Washington Heights-Hamilton Heights-Inwood Columbia Aging Project (WHICAP)

INTRODUCTION

High dietary intake of long chain, polyunsaturated fatty acids is associated with lower Alzheimer's disease (AD) risk.

METHODS

Washington Heights-Hamilton Heights-Inwood Columbia Aging Project is a multiethnic, prospective observational study of aging and dementia among elderly (≥ 65 years). Dietary intake was measured using a food frequency questionnaire. Dietary short-, medium-, and long-chain fatty acid intakes were categorized by number of carbons and double bonds. Consensus AD diagnoses were made. Associations between AD risk and dietary fatty acid and cholesterol intakes were estimated using multivariable Cox proportional hazards regression models.

RESULTS

Of 2612 multiethnic women (67%) and men (baseline age 76.3 [6.4] years), 380 developed AD over an average 4.5 years follow-up. Lower risk of AD was associated with increasing intakes of docosahexaenoic acid (DHA; hazard ratio [HR] = 0.73, 95% confidence interval [CI]: 0.57 to 0.95, P = 0.018) and eicosapentaenoic acid (EPA; HR = 0.74, 95% CI: 0.57 to 0.95, P = 0.021), and longer AD-free survival (P < 0.05).

DISCUSSION

Higher intake of DHA and EPA are protective for AD.

Prevalence and incidence of dementia in an older Chinese population over two decades: The role of education

INTRODUCTION

Secular trends of dementia prevalence and incidence have rarely been studied in the Chinese population.

METHODS

We examined the changes in dementia prevalence and incidence by comparing data from Shanghai Epidemiological Survey of Dementia and Alzheimer's disease (SESD) and Shanghai Aging Study (SAS) conducted two decades apart.

FINDINGS

The dementia prevalence and incidence in total participants in SAS were higher than that in SESD (prevalence: 6.44% vs 2.30%, P < .001; annual incidence: 2.58% vs 1.33%, P < .001). In participants with ≤6 years of education, the dementia prevalence in SAS was higher than that in SESD (6.39% vs 3.07%, P < .001); the annual dementia incidence in SAS was double that in SESD (3.63% vs 1.80%, P = .019).

DISCUSSION

We observed an increasing trend of dementia prevalence and incidence in the Chinese elderly, especially those with low education. The dramatic rise in numbers of people with dementia may happen most likely in low-educated populations.

Medicaid Contributes Substantial Costs to Dementia Care in an Ethnically Diverse Community

OBJECTIVES

The main objective of this study was to estimate effects of dementia on Medicaid expenditures in an ethnically diverse community.

METHODS

The sample included 1,211 Medicare beneficiaries who did not have any Medicaid coverage and 568 who additionally had full Medicaid coverage enrolled in the Washington Heights-Inwood Columbia Aging Project (WHICAP), a multiethnic, population-based, prospective study of cognitive aging in northern Manhattan (1999-2010). Individuals' dementia status was determined using a rigorous clinical protocol. Relationship between dementia and Medicaid coverage and expenditures were estimated using a two-part model.

RESULTS

In participants who had full Medicaid coverage, average annual Medicaid expenditures were substantially higher for those with dementia than those without dementia ($50,270 vs. $21,966, p < .001), but Medicare expenditures did not differ by dementia status ($8,458 vs. $9,324, p = .19). In participants who did not have any Medicaid coverage, average annual Medicare expenditures were substantially higher for those with dementia than those without dementia ($12,408 vs. $8,113, p = .02). In adjusted models, dementia was associated with a $6,278 increase in annual Medicaid spending per person after controlling for other characteristics.

DISCUSSION

Results highlight Medicaid's contribution to covering the cost of dementia care in addition to Medicare. Studies that do not include Medicaid are unlikely to accurately reflect the true cost of dementia.

Twenty-seven-year time trends in dementia incidence in Europe and the United States: The Alzheimer Cohorts Consortium

OBJECTIVE

To determine changes in the incidence of dementia between 1988 and 2015.

METHODS

This analysis was performed in aggregated data from individuals >65 years of age in 7 population-based cohort studies in the United States and Europe from the Alzheimer Cohort Consortium. First, we calculated age- and sex-specific incidence rates for all-cause dementia, and then defined nonoverlapping 5-year epochs within each study to determine trends in incidence. Estimates of change per 10-year interval were pooled and results are presented combined and stratified by sex.

RESULTS

Of 49,202 individuals, 4,253 (8.6%) developed dementia. The incidence rate of dementia increased with age, similarly for women and men, ranging from about 4 per 1,000 person-years in individuals aged 65-69 years to 65 per 1,000 person-years for those aged 85-89 years. The incidence rate of dementia declined by 13% per calendar decade (95% confidence interval [CI], 7%-19%), consistently across studies, and somewhat more pronouncedly in men than in women (24% [95% CI 14%-32%] vs 8% [0%-15%]).

CONCLUSION

The incidence rate of dementia in Europe and North America has declined by 13% per decade over the past 25 years, consistently across studies. Incidence is similar for men and women, although declines were somewhat more profound in men. These observations call for sustained efforts to finding the causes for this decline, as well as determining their validity in geographically and ethnically diverse populations.

A New Look at Cohort Trend and Underlying Mechanisms in Cognitive Functioning

OBJECTIVES

The prevalence of dementia in the United States seems to have declined over the last few decades. We investigate trends and their underlying mechanisms in cognitive functioning (CF) across 7 decades of birth cohorts from the Greatest Generation to Baby Boomers.

METHODS

Data come from 30,191 participants of the 1996-2014 Health and Retirement Study. CF is measured as a summary score on a 35-point cognitive battery of items. We use generalized linear models to examine the trends in CF and explanatory variables across birth cohorts. Then, Karlson-Holm-Breen decomposition method is used to evaluate the contribution of each explanatory variable to the trend of CF.

RESULTS

CF has been improving from the Greatest Generation to Late Children of Depression and War Babies, but then significantly declines since the Early-Baby Boomers and continues into Mid-Baby Boomers. This pattern is observed universally across genders, race/ethnicities, education groups, occupations, income, and wealth quartiles. The worsening CF among Baby Boomers does not originate from childhood conditions, adult education, or occupation. It can be attributed to lower household wealth, lower likelihood of marriage, higher levels of loneliness, depression and psychiatric problems, and more cardiovascular risk factors (e.g., obesity, physical inactivity, hypertension, stroke, diabetes, and heart disease).

DISCUSSION

The worsening CF among Baby Boomers may potentially reverse past favorable trends in dementia as they reach older ages and cognitive impairment becomes more common if no effective interventions and policy responses are in place.

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

IMPORTANCE

Early-life factors may be important for later dementia risk. The association between a more advantaged early-life environment, as reflected through an individual's height and socioeconomic status indicators, and decreases in dementia incidence by birth cohort is unknown.

OBJECTIVES

To examine the association of birth cohort and early-life environment with dementia incidence among participants in the Adult Changes in Thought study from 1994 to 2015.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cohort study included 4277 participants from the Adult Changes in Thought study, an ongoing longitudinal population-based study of incident dementia in a random sample of adults 65 years and older who were born between 1893 and 1949 and are members of Kaiser Permanente Washington in the Seattle region. Participants in the present analysis were followed up from 1994 to 2015. At enrollment, all participants were dementia-free and completed a baseline evaluation. Subsequent study visits were held every 2 years until a diagnosis of dementia, death, or withdrawal from the study. Participants were categorized by birth period (defined by historically meaningful events) into 5 cohorts: pre-World War I (1893-1913), World War I and Spanish influenza (1914-1920), pre-Great Depression (1921-1928), Great Depression (1929-1939), and World War II and postwar (1940-1949). Participants' height, educational level, childhood financial stability, and childhood household density were examined as indicators of early-life environment, and later-life vascular risk factors for dementia were assessed. Cox proportional hazards regression models, adjusted for competing survival risk, were used to analyze data. Data were analyzed from June 1, 2018, to April 29, 2020.

MAIN OUTCOMES AND MEASURES

Participants completed the Cognitive Abilities Screening Instrument every 2 years to assess global cognition. Those with scores indicative of cognitive impairment completed an evaluation for dementia, with dementia diagnoses determined during consensus conferences using criteria from the Diagnostic and Statistical Manual of Mental Disorders, 4th edition.

RESULTS

Among 4277 participants, the mean (SD) age was 74.5 (6.4) years, and 2519 participants (58.9%) were women. The median follow-up was 8 years (interquartile range, 4-12 years), with 730 participants developing dementia over 24 378 person-years. The age-specific dementia incidence was lower for those born in 1929 and later compared with those born earlier. Compared with participants born in the pre-Great Depression years (1921-1928), the age- and sex-adjusted hazard ratio was 0.67 (95% CI, 0.53-0.85) for those born in the Great Depression period (1929-1939) and 0.62 (95% CI, 0.29-1.31) for those born in the World War II and postwar period (1940-1949). Although indicators of a more advantaged early-life environment and higher educational level (college or higher) were associated with a lower incidence of dementia, these variables did not explain the association between birth cohort and dementia incidence, which remained when vascular risk factors were included and were similar by sex.

CONCLUSIONS AND RELEVANCE

Age-specific dementia incidence was lower in participants born after the mid-1920s compared with those born earlier. In this population, the decrease in dementia incidence may reflect societal-level changes or individual differences over the life course rather than early-life environment, as reflected through recalled childhood socioeconomic status and measured height, educational level, and later-life vascular risk.

Traditional Chinese Medicine for Alzheimer's Disease and Other Cognitive Impairment: A Review

Cognitive impairment (CI) refers to the dysfunction of memory, language, visual space, execution, calculation, understanding, and judgment in one or more aspects. With global aging, CI will become prevalent worldwide. At present, there is no effective cure for CI. However, Nobel laureate Tu Youyou's research on artemisinin has inspired Chinese researchers to focus on traditional Chinese herbs (TCHs) for the treatment of CI. Traditional Chinese Medicine (TCM) has led to a theory for an independent CI system. The pathogenesis of such impairment involves deficiency, phlegm, and stagnation and involves a range of organs, including the brain, kidneys, heart, liver, and spleen. Our current understanding of the etiology and pathogenesis of this condition has led to the realization that TCHs can improve cognitive dysfunction. Clinical research has shown that TCHs can improve the neuropsychological scale score of patients, the TCM symptom score, and the patient's quality of life. Research has also suggested that TCHs can retard Aβ deposits and tauopathy, regulate the metabolism of cholinergic neurotransmitters, and so on. However, due to their complexity, little is known of the safety and efficacy of TCHs in patients with CI. It is likely that we will be able to identify the precise mechanisms associated with the action of TCHs in such patients due to the integration of multiple technologies. This paper summarizes the pharmacokinetics, curative effect, and mechanisms of action of traditional Chinese herbs in order to provide a scientific basis for the improvement of cognitive dysfunction by TCHs.

Secular changes in dementia risk indices among 70-year-olds: a comparison of two Finnish cohorts born 20 years apart

AIMS

To compare dementia risk indices among two separate cohorts of 70-year-olds born 20 year apart.

METHODS

Community-dwelling 70-year-old Finns were examined with similar examinations in 1991 (n = 1032) and in 2011 (n = 960). Dementia risk was assessed with the CAIDE Dementia Risk Score (CAIDE) (n = 1516), the Brief Dementia Risk Index (BDRI) (n = 1598) and the Dementia Screening Indicator (DSI) (n = 1462).

RESULTS

The proportion of subjects with moderate or high risk for dementia was significantly higher in earlier than in later born cohort according to CAIDE (99% and 94%, respectively, p < 0.001) and BDRI (41% and 15%, p < 0.001), but not according to DSI (5% and 6%, p = 0.184). The total scores of the earlier born cohort were significantly higher than those of the later born cohort according to all three indices.

CONCLUSIONS

According to dementia risk indices, it seems that dementia risk has decreased among community-dwelling 70-year-old subjects during the last decades in Finland.

Functional deficits and other psychiatric associations with abnormal scores on the Montreal Cognitive Assessment (MoCA) in older HIV-infected patients

OBJECTIVE

The authors assessed the association of physical function, social variables, functional status, and psychiatric co-morbidity with cognitive function among older HIV-infected adults.

DESIGN

From 2012-2014, a cross-sectional study was conducted among HIV-infected patients ages 50 or older who underwent comprehensive clinical geriatric assessment.

SETTING

Two San Francisco HIV clinics.

PARTICIPANTS

359 HIV-infected patients age 50 years or older.

MEASUREMENTS

Unadjusted and adjusted Poisson regression measured prevalence ratios and 95% confidence intervals for demographic, functional and psychiatric variables and their association with cognitive impairment using a Montreal Cognitive Assessment (MoCA) score < 26 as reflective of cognitive impairment.

RESULTS

Thirty-four percent of participants had a MoCA score of < 26. In unadjusted analyses, the following variables were significantly associated with an abnormal MoCA score: born female, not identifying as homosexual, non-white race, high school or less educational attainment, annual income < $10,000, tobacco use, slower gait speed, reported problems with balance, and poor social support. In subsequent adjusted analysis, the following variables were significantly associated with an abnormal MoCA score: not identifying as homosexual, non-white race, longer 4-meter walk time, and poor social support. Psychiatric symptoms of depressive, anxiety, and post-traumatic stress disorders did not correlate with abnormal MoCA scores.

CONCLUSIONS

Cognitive impairment remains common in older HIV-infected patients. Counter to expectations, co-morbid psychiatric symptoms were not associated with cognitive impairment, suggesting that cognitive impairment in this sample may be due to neurocognitive disorders, not due to other psychiatric illness. The other conditions associated with cognitive impairment in this sample may warrant separate clinical and social interventions to optimize patient outcomes.

Secular trends in cognitive trajectories of diverse older adults

INTRODUCTION

This study aimed to determine if later birth year influences trajectory of age-related cognitive decline across racial/ethnic groups and to test whether years of school, childhood socioeconomic status, and cardiovascular disease burden explain such secular trends.

METHODS

We compared cognitive trajectories of global cognition and subdomains in two successive racially/ethnically and educationally diverse birth cohorts of a prospective cohort study.

RESULTS

Later birth year was associated with higher initial cognitive levels for Whites and Blacks, but not Hispanics. Later birth year was also associated with less rapid rate of decline in all three racial/ethnic groups. More years of education, higher childhood socioeconomic status, and, to a smaller extent, greater cardiovascular disease burden accounted for higher intercepts in the later-born cohort, but did not account for attenuated slope of cognitive decline.

DISCUSSION

Later birth year is related to a slower rate of age-related decline in some cognitive domains in some racial/ethnic groups. Our analyses suggest that racial/ethnic and social inequalities are part of the mechanisms driving secular trends in cognitive aging and dementia.

Secular Trends in Dementia Prevalence and Incidence Worldwide: A Systematic Review

BACKGROUND

Time trends for dementia prevalence and incidence rates have been reported over the past seven decades in different countries and some have reported a decline.

OBJECTIVE

To undertake a systematic review to critically appraise and provide an evidence-based summary of the magnitude and direction of the global changes in dementia prevalence and incidence across time.

METHODS

Medline, EMBASE, and PsychINFO were searched for studies focused on secular trends in dementia prevalence and/or incidence until 18 December 2017. In total, 10,992 articles were identified and 43 retained.

RESULTS

Overall, prevalence rates are largely increasing (evidence primarily from record-based surveys and cohort studies in Japan, Canada, and France) or have remained stable (evidence primarily from cohort studies in Sweden, Spain and China). A significant decline in prevalence has however been reported in more recent studies (i.e., from 2010 onwards) from Europe (e.g., UK and Sweden) and the USA. Incidence rates have generally remained stable or decreased in China, Canada, France, Germany, Denmark, Sweden, the Netherlands, UK, and USA. An increase has only been reported in five countries: Italy, Japan, Wales, Germany, and the Netherlands. Only one study reported findings (stability in incidence) from a low and middle-income country using data from Nigeria.

CONCLUSIONS

The evidence on secular trends in the prevalence and incidence of dementia is mixed including contradictory findings using different (and in some cases the same) datasets in some countries (e.g., the USA, UK, and Sweden). This making it difficult to draw concrete conclusions. However, declining trends recently observed in some high-income Western countries in the most recent two decades including the UK, USA, and Sweden are encouraging. Updated dementia prevalence and incidence estimates will inform public health and financial planning as well as development of prevention strategies.

Alzheimer's dementia: pathogenesis and impact of cardiovascular risk factors on cognitive decline

Alzheimer's disease (AD) is the most common form of dementia manifesting as alterations in cognitive abilities, behavior, and deterioration in memory which is progressive, leading to gradual worsening of symptoms. Major pathological features of AD are accumulations of neuronal amyloid plaques and neurofibrillary tangles, with early lesions appearing primarily in the hippocampus, the area of the brain involved in memory and learning. Cardiovascular-related risk factors are believed to play a crucial role in disease development and the acceleration of cognitive deterioration by worsening cerebral perfusion, promoting disturbances in amyloid clearance. Current evidence supports hypertension, hypotension, heart failure, stroke and coronary artery diseases as potential factors playing a role in cognitive decline in patients with Alzheimer's dementia. Although dementia due to cardiovascular deficits is more strongly linked to the development of vascular dementia, a stepwise decline in cognition, recent researches have also discovered its deleterious influence on AD development.

Declining Incident Dementia Rates Across Four Population-Based Birth Cohorts

BACKGROUND

Incidence rates of dementia appear to be declining in high-income countries according to several large epidemiological studies. We aimed to describe declining incident dementia rates across successive birth cohorts in a U.S. population-based sample and to explore the influences of sex and education on these trends.

METHODS

We pooled data from two community-sampled prospective cohort studies with similar study aims and contiguous sampling regions: the Monongahela Valley Independent Elders Survey (1987-2001) and the Monongahela-Youghiogheny Healthy Aging Team (2006-Ongoing). We identified four decade-long birth cohorts spanning birth years 1902-1941. In an analysis sample of 3,010 participants (61% women, mean baseline age = 75.7 years, mean follow-up = 7.1 years), we identified 257 cases of incident dementia indicated by a Clinical Dementia Rating of 1.0 or higher. We used Poisson regression to model incident dementia rates by birth cohort, age, sex, education, and interactions of Sex × Cohort and Sex × Education. We further examined whether cohort effects varied by education, testing a Cohort × Education interaction and stratifying the models by education.

RESULTS

Compared to the earliest birth cohort (1902-1911), each subsequent cohort had a significantly lower incident dementia rate (1912-1921: incidence rate ratio [IRR] = 0.655, 95% confidence interval [95% CI] = 0.477-0.899; 1922-1931: IRR = 0.387, 95% CI = 0.265-0.564; 1932-1941: IRR = 0.233, 95% CI = 0.121-0.449). We observed no significant interactions of either sex or education with birth cohort.

CONCLUSIONS

A decline in incident dementia rates was observed across successive birth cohorts independent of sex, education, and age.

Metabolic Syndrome, Mild Cognitive Impairment, and Dementia: A Meta-Analysis of Longitudinal Studies

OBJECTIVE

A systematic review and a meta-analysis of both clinical and population-based studies was undertaken according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement to clarify whether Metabolic Syndrome (MetS) is a risk or a protective factor for incident dementia, Alzheimer disease (AD), and vascular dementia (VaD), and whether it's involved in progression to dementia in patients affected by mild cognitive impairment (MCI).

METHODS

Search terms included ("metabolic syndrome" OR "syndrome x" OR "plurimetabolic syndrome") AND ("dementia" OR "Alzheimer disease" OR "vascular dementia" OR "mild cognitive impairment" OR "MCI"). Research was restricted to articles published in English between January 1, 2000 and August 31, 2018. No age limit was set.

RESULTS

At the end of the selection procedure, nine longitudinal studies were selected for the meta-analysis: six studies enrolled cognitively well-functioning participants and three studies involved MCI patients. A total of 18,313 participants aged older than 40 years with mean MetS prevalence of 22.7% were followed on average for 9.41years. A fixed model was used to estimate pooled hazard ratios and 95% confidence intervals.

CONCLUSION

No statistically significant pooled association emerged between MetS and incident dementia and AD. MetS increased the incidence of pure VaD. MetS increased the risk of progression from MCI to dementia. Follow-up length might be a key factor in investigating these associations further. Because MetS is constituted by a set of potentially modifiable factors, further studies with longer follow-up and repeated assessment of both MetS and cognitive status are desirable to draw definite conclusions.

Risk of dementia and mild cognitive impairment among older adults in same-sex relationships

INTRODUCTION

Sexual minority discrimination might lead to a higher risk of mild cognitive impairment (MCI) and dementia. The aim of this study was to assess the risk of MCI and dementia between older adults in same-sex relationships (SSR) and opposite-sex relationships (OSR).

METHODS

We analyzed longitudinal data from the National Alzheimer's Coordinating Center up to September 2017. Analyses included cognitively normal individuals 55+ at baseline who had a spouse, partner, or companion as study partner at any assessment. Associations were calculated using survival analysis adjusting for demographics and APOE-e4 carrier status.

RESULTS

Hazard ratios of MCI and dementia did not differ statistically between SSR and OSR individuals in the total sample nor stratified by sex.

CONCLUSION

The lack of association between SSR and MCI and dementia warrants future research into their potential resilience mechanisms and the inclusion of sexual minority status questions in research and surveillance studies. The potential recruitment bias caused by nonprobabilistic sampling of the cohort and the reporting and ascertainment bias caused by using SSR to infer sexual minority status may have influenced our findings.

Aging without Dementia is Achievable: Current Evidence from Epidemiological Research

Both the incidence and the prevalence of dementia increase exponentially with increasing age. This raises the question of whether dementia is an inevitable consequence of aging or whether aging without dementia is achievable. In this review article, we sought to summarize the current evidence from epidemiological and neuropathological studies that investigated this topic. Epidemiological studies have shown that dementia could be avoided even at extreme old ages (e.g., centenarians or supercentenarians). Furthermore, clinico-neuropathological studies found that nearly half of centenarians with dementia did not have sufficient brain pathology to explain their cognitive symptoms, while intermediate-to-high Alzheimer pathology was present in around one-third of very old people without dementia or cognitive impairment. This suggests that certain compensatory mechanisms (e.g., cognitive reserve or resilience) may play a role in helping people in extreme old ages escape dementia syndrome. Finally, evidence has been accumulating in recent years indicating that the incidence of dementia has declined in Europe and North America, which supports the view that the risk of dementia in late life is modifiable. Evidence has emerged that intervention strategies that promote general health, maintain vascular health, and increase cognitive reserve are likely to help preserve cognitive function till late life, thus achieving the goal of aging without dementia.

Brain MRI findings related to Alzheimer's disease in older African American adults

Although a substantial body of research has identified brain MRI measures as important markers of Alzheimer's disease (AD) risk, progression, and treatment response, most of that research has been performed in non-Hispanic white American populations, leading to questions about the utility of the brain MRI measures among individuals of other races or ethnicities. African American individuals in particular are under-represented in AD research, and may exhibit differences in prevalence of AD risk factors, prevalence of AD, incidence of AD, the clinical course of cognitive decline, and AD neuropathology, each of which could influence the utility of brain MRI markers. Unfortunately, while current evidence suggests that African Americans exhibit poorer brain health late in life based on brain MRI measurements, several other aspects of brain MRI markers in this population are unclear, including trajectories of brain MRI markers leading up to old age, relationships between traditional brain health risk factors and brain MRI findings, and the status of brain MRI markers as correlates of cognitive impairment. This unclear state of affairs highlights the urgency of future research in which large numbers of older African American adults contribute longitudinal brain MRI measurements concurrent with clinical, cognitive, and molecular biomarker measurements, ideally in the context of AD preventive or therapeutic trials.

Cohort Differences in Cognitive Impairment and Cognitive Decline Among Mexican-Americans Aged 75 Years or Older

Research suggests that the prevalence and incidence of cognitive impairment among older adults is decreasing. This analysis used data from 9 waves (1993-2016) of the Hispanic Established Populations for the Epidemiologic Study of the Elderly to assess cognitive status and cognitive decline for 2 cohorts of Mexican-Americans aged ≥75 years in 1993-1994 versus 2004-2005. Logistic regression, joint longitudinal survival models, and illness-death models for interval-censored data were used to examine cohort differences in the odds of prevalent cognitive impairment, trajectories of cognitive decline, and the risk of 10-year incident cognitive impairment, respectively. Results indicated that compared with the 1993-1994 cohort, the 2004-2005 cohort had higher odds for prevalent cognitive impairment (odds ratio = 2.51, 95% confidence interval (CI): 1.92, 3.29), particularly among participants with <4 years of education (odds ratio = 2.99, 95% CI: 2.14, 4.18). Conversely, the 2004-2005 cohort exhibited significantly slower rates of cognitive decline (βˆ = 0.50, 95% CI: 0.39, 0.62) and had a significantly lower risk of incident cognitive impairment (hazard ratio = 0.75, 95% CI: 0.62, 0.91) compared with the 1993-1994 cohort. This analysis provides mixed results for cohort trends in the cognitive health of older Mexican-Americans. Continued research is needed to identify risk factors that contribute to these population-level trends.

Periodontal status among elderly inhabitants of northern Manhattan: The WHICAP ancillary study of oral health

AIM

We conducted a cross-sectional study of the prevalence, extent and severity of periodontitis in a tri-ethnic cohort of ≥65 year-old participants of the Washington-Heights Inwood Community Aging Project (WHICAP).

METHODS

1,130 individuals (57% of eligible invitees) participated in a full-mouth periodontal examination that included assessments of bleeding on probing, pocket depth and clinical attachment loss (CAL) at six sites/tooth.

RESULTS

Participants had a mean age of 75.4 years (SD 6.7), were predominantly female (66.6%) and Hispanic (44.7%), and of middle/low educational attainment (~82%). The prevalence of edentulism was 14.7%, and an average of 17.1 teeth (SD 8.0) was present among the dentate. The prevalence of moderate/severe periodontitis according to the CDC/AAP definition was 77.5%. Pockets ≥6 mm were found in 50.2% of the sample, affecting an average of 5.7% of teeth/person. Corresponding figures for CAL≥5 mm were 71.4% and 23.6%, respectively. In multivariable models, male gender, being Black or Hispanic, and no dental visit within the prior year were associated with higher proportion of teeth with CAL ≥5 mm.

CONCLUSIONS

The prevalence, extent and severity of periodontitis were higher than the US national average in this urban elderly sample, suggesting substantial unmet periodontal treatment needs.

Secular Trends in Cognitive Performance in Older Black and White U.S. Adults, 1993-2012: Findings From the Chicago Health and Aging Project

Objective

To characterize secular trends from 1993 to 2012 in cognitive performance using a cohort of older black and white U.S. adults, and compare trends by race.

Method

Our data come from 8,906 participants of the Chicago Health and Aging Project (CHAP), a longitudinal, population-based cohort (age ≥ 67, 60% black). Participants underwent cognitive assessments in six 3-year study cycles from 1993 to 1996 through 2010 to 2012. We computed 3 measures of cognitive performance: global cognition, episodic memory, and perceptual speed.

Results

Mean performance in terms of global cognitive score followed a secular pattern of modest decline over the 6 study cycles. The trend was most pronounced for perceptual speed. Mean scores among black participants were consistently lower than those for whites; these disparities in mean performance narrowed over time, especially on perceptual speed, but appeared to widen at the last cycle. Global scores among the upper quartile of performers rose slightly, but scores among the lowest quartile of performers dropped precipitously.

Discussion

Between 1993 and 2012, secular trends in cognitive performance in this established cohort did not follow a clear pattern of improvement, contrasting with previous research. But patterns differed by cognitive domain, performance level, and race.