Sources of variability in estimates of the prevalence of Alzheimer's disease in the United States

Prevalence of DSM-5 mild and major neurocognitive disorder in India: Results from the LASI-DAD

INTRODUCTION

India, with its rapidly aging population, faces an alarming burden of dementia. We implemented DSM-5 criteria in large-scale, nationally representative survey data in India to characterize the prevalence of mild and major Neurocognitive disorder.

METHODS

The Harmonized Diagnostic Assessment of Dementia for the Longitudinal Aging Study in India (LASI-DAD) (N = 4,096) is a nationally representative cohort study in India using multistage area probability sampling methods. Using neuropsychological testing and informant reports, we defined DSM-5 mild and major neurocognitive disorder, reported its prevalence, and evaluated criterion and construct validity of the algorithm using clinician-adjudicated Clinical Dementia Ratings (CDR)®.

RESULTS

The prevalence of mild and major neurocognitive disorder, weighted to the population, is 17.6% and 7.2%. Demographic gradients with respect to age and education conform to hypothesized patterns. Among N = 2,390 participants with a clinician-adjudicated CDR, CDR ratings and DSM-5 classification agreed for N = 2,139 (89.5%) participants.

DISCUSSION

The prevalence of dementia in India is higher than previously recognized. These findings, coupled with a growing number of older adults in the coming decades in India, have important implications for society, public health, and families. We are aware of no previous Indian population-representative estimates of mild cognitive impairment, a group which will be increasingly important in coming years to identify for potential therapeutic treatment.

Estimating the Prevalence of Dementia and Mild Cognitive Impairment in the US: The 2016 Health and Retirement Study Harmonized Cognitive Assessment Protocol Project

Importance

Nationally representative data are critical for understanding the causes, costs, and outcomes associated with dementia and mild cognitive impairment (MCI) in the US and can inform policies aimed at reducing the impact of these conditions on patients, families, and public programs. The nationally representative Health and Retirement Study (HRS) is an essential resource for such data, but the HRS substudy providing dementia diagnostic information was fielded more than 20 years ago and more recent data are needed.

Objective

The Harmonized Cognitive Assessment Protocol (HCAP) was developed to update national estimates of the prevalence of MCI and dementia in the US and examine differences by age, race, ethnicity, and sex.

Design, Setting, and Participants

HRS is an ongoing longitudinal nationally representative study of people 51 years and older with staggered entry dates from 1992 to 2022 and follow-up ranging from 4 to 30 years. HCAP is a cross-sectional random sample of individuals in HRS who were 65 years or older in 2016. Of 9972 age-eligible HRS participants, 4425 were randomly selected for HCAP, and 3496 completed a comprehensive neuropsychological test battery and informant interview, none of whom were excluded. Dementia and MCI were classified using an algorithm based on standard diagnostic criteria and comparing test performance to a robust normative sample.

Exposures

Groups were stratified by age, sex, education, race, and ethnicity.

Main Outcomes and Measures

National prevalence estimates using population weights.

Results

The mean (SD) age of the study population sample (N = 3496) was 76.4 (7.6) years, and 2095 participants (60%) were female. There were 551 participants who self-identified as Black and not Hispanic (16%), 382 who self-identified as Hispanic regardless of race (16%), 2483 who self-identified as White and not Hispanic (71%), and 80 who self-identified as another race (2%), including American Indian or Alaska Native, Asian, Native Hawaiian or Pacific Islander, or another self-described race. A total of 393 individuals (10%; 95% CI, 9-11) were classified as having dementia and 804 (22%; 95% CI, 20-24) as having MCI. Every 5-year increase in age was associated with higher risk of dementia (weighted odds ratio [OR], 1.95 per 5-year age difference; 95%, CI, 1.77-2.14) and MCI (OR, 1.17 per 5-year age difference, 95% CI, 1.09-1.26). Each additional year of education was associated with a decrease in risk of dementia (OR, 0.93 per year of school, 95% CI, 0.89-0.97) and MCI (OR, 0.94, 95% CI, 0.91-0.97). Dementia was more common among non-Hispanic Black individuals (OR, 1.81; 95% CI, 1.20-2.75) and MCI in Hispanic individuals (OR, 1.42; 95% CI, 1.03-1.96) compared with non-Hispanic White individuals. Other group comparisons by race and ethnicity were not possible owing to small numbers. No differences in prevalence were found between female individuals and male individuals.

Conclusions and Relevance

Using a comprehensive neuropsychological test battery and large sample, the national prevalence of dementia and MCI in 2016 found in this cross-sectional study was similar to that of other US-based studies, indicating a disproportionate burden of dementia and MCI among older Black and Hispanic adults and those with lower education.

Accounting for lack of representation in dementia research: Generalizing KHANDLE study findings on the prevalence of cognitive impairment to the California older population

INTRODUCTION

Most dementia studies are not population-representative; statistical tools can be applied to samples to obtain critically-needed population-representative estimates, but are not yet widely used.

METHODS

We pooled data from the Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) study and the California Behavioral Risk Factor Surveillance System (CA-BRFSS), a population-representative study. Using weights accounting for sociodemographic/health differences between KHANDLE and CA-BRFSS, we estimated cognitive impairment prevalence and age- and sex-adjusted racial/ethnic inequalities in California adults 65+ without prior dementia diagnosis.

RESULTS

After weighting KHANDLE, the estimated cognitive impairment prevalence in California was 20.3% (95% confidence interval 17.8-23.0); unweighted prevalence was 24.8% (23.1%-26.6%). Inequalities (larger prevalences) were observed among Black and Asian groups versus whites.

DISCUSSION

We used a novel statistical approach to estimate population-representative cognitive impairment prevalence and inequalities. Such statistical tools can help obtain population-representative estimates from existing studies and inform efforts to reduce racial/ethnic disparities.

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.

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.

Estimation of dementia prevalence at the local level in the United States

INTRODUCTION

Ensuring adequate and equitable distribution of resources to support persons living with dementia relies on understanding the burden and distribution of dementia in a population. Our goal was to develop an approach to estimate dementia prevalence at the local level in the United States using publicly available data.

METHODS

Our approach combines publicly available data on dementia prevalence and demographic data from the US Census to estimate dementia prevalence. We illustrate this approach by estimating dementia prevalence in persons aged 65 and older in Philadelphia, PA; Chicago, IL; and Atlanta, GA.

RESULTS

Overall, we estimate the prevalence of dementia among those 65 and older to be 11.9% in Philadelphia, 11.8% Chicago, and 12.3% in Atlanta. Estimates across Philadelphia localities vary from 9.3% to 15.9%.

DISCUSSION

Our approach provides a cost-effective method to generate estimates of dementia prevalence at the local level.

HIGHLIGHTS

Brain health needs assessments require understanding of local dementia prevalence.Our approach can be used to estimate dementia prevalence in individual communities.This information can inform decisions about distribution of resources.

2021 Alzheimer's disease facts and figures

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

Estrogen receptor involvement in vascular cognitive impairment and vascular dementia pathogenesis and treatment

Vascular cognitive impairment (VCI) is a term that encompasses a continuum of cognitive disorders with cerebrovascular pathology contribution, ranging from mild cognitive impairment to vascular dementia (VaD). VCI and VaD, thus, represent an interesting intersection between cardiovascular disease and neurodegenerative disorders such as Alzheimer's disease (AD) and a rising area of research in recent years. Although VCI and VaD research has identified various causes and explanations for disease development, many aspects remain unclear, particularly sex differences in VCI (e.g., epidemiology), unlike those available for cardiovascular disease and AD. Despite limited information in the literature, several studies have observed an association of estrogen receptor (ER) polymorphisms and VaD. If further explored, this association could provide valuable insights for novel therapeutic approaches. This review aims to provide a brief epidemiological overview and subsequent discussion exploring concepts of brain aging and involvement of estrogen receptors in potential mechanisms of VCI/VaD pathogenesis and treatment development.

Effect of AmyTrap, an amyloid-β binding drug, on Aβ induced mitochondrial dysfunction and tau phosphorylation in cultured neuroblastoma cells

Alzheimer's Disease (AD) is the most common cause of dementia, affecting 25 million people worldwide. Accumulation of Amyloid-β (Aβ) in the mitochondria has been shown to adversely affect key enzymes including pyruvate dehydrogenase (PDH), succinate dehydrogenase (SDH), oxoglutarate dehydrogenase (OGDH). Accumulation of Aβ is also believed to increase Tau expression and pathology. Tau, in its toxic state, results in synaptic damage causing memory and cognitive dysfunction. We are developing a drug to treat AD namely AmyTrap. The active pharmacological ingredient is a retro inverso, Aβ-binding peptide which sequesters Aβ. We wanted to examine the effect of AmyTrap peptide on Aβ-induced mitochondrial dysfunction and Tau phosphorylation. Therefore, we treated SH-SY5Y neuroblastoma cells with wild-type Aβ, a mutant AβY10A, AmyTrap peptide (RI-peptide), or Aβ and RI-peptide for 72 h. The mutant AβY10A is known to impact the self-aggregating property of Aβ as this Tyr10 is essential for self-aggregation. As expected, AβY10A reversed PDH, OGDH and SDH dysfunction to near normal levels. Further, AβY10A successfully reversed Tau phosphorylation, suggesting that Tyr10 is also associated with Aβ-induced cytotoxicity. RI-peptide was able to significantly reverse SDH dysfunction with limited effect on PDH and Tau phosphorylation. The findings are suggestive that the Tyr10 on Aβ plays a critical role in the self-aggregation. Further studies are warranted to expand these findings.

2020 Alzheimer's disease facts and figures

This article describes the public health impact of Alzheimer's disease (AD), including incidence and prevalence, mortality and morbidity, use and costs of care, and the overall impact on caregivers and society. The Special Report discusses the future challenges of meeting care demands for the growing number of people living with Alzheimer's dementia in the United States with a particular emphasis on primary care. By mid-century, the number of Americans age 65 and older with Alzheimer's dementia may grow to 13.8 million. This represents a steep increase from the estimated 5.8 million Americans age 65 and older who have Alzheimer's dementia today. Official death certificates recorded 122,019 deaths from AD in 2018, the latest year for which data are available, making Alzheimer's the sixth leading cause of death in the United States and the fifth leading cause of death among Americans age 65 and older. Between 2000 and 2018, deaths resulting from stroke, HIV and heart disease decreased, whereas reported deaths from Alzheimer's increased 146.2%. In 2019, more than 16 million family members and other unpaid caregivers provided an estimated 18.6 billion hours of care to people with Alzheimer's or other dementias. This care is valued at nearly $244 billion, but its costs extend to family caregivers' increased risk for emotional distress and negative mental and physical health outcomes. Average per-person Medicare payments for services to beneficiaries age 65 and older with AD or other dementias are more than three times as great as payments for beneficiaries without these conditions, and Medicaid payments are more than 23 times as great. Total payments in 2020 for health care, long-term care and hospice services for people age 65 and older with dementia are estimated to be $305 billion. As the population of Americans living with Alzheimer's dementia increases, the burden of caring for that population also increases. These challenges are exacerbated by a shortage of dementia care specialists, which places an increasing burden on primary care physicians (PCPs) to provide care for people living with dementia. Many PCPs feel underprepared and inadequately trained to handle dementia care responsibilities effectively. This report includes recommendations for maximizing quality care in the face of the shortage of specialists and training challenges in primary care.

Interaction of opioid with insulin/IGFs signaling in Alzheimer's disease

Alzheimer's disease is associated with biochemical and histopathological changes characterized by molecular abnormalities. Due to the lack of effective treatments for Alzheimer's disease, many attempts have been made to find potential therapies to reduce or even return neuronal loss after disease initiation. Alzheimer's disease is also touted as type III diabetes, showing an association with insulin signaling. The large distribution of the insulin receptor on the cell surface and its regulatory role in the central nervous system suggests that the pathogenesis of Alzheimer's disease could be ascribed to insulin signaling. The interference of opioids, such as morphine with insulin signaling pathways, is thought to occur via direct crosstalk between the signaling pathways of the insulin receptor and the mu-opioid receptor. In this review article, we discuss the possible crosstalk between the mu-opioid receptor and insulin signaling pathways. The association of these two signaling pathways with Alzheimer's disease is also debated.

Temporal and Geographic Variation in the Incidence of Alzheimer's Disease Diagnosis in the US between 2007 and 2014

OBJECTIVES

Our aim was to describe the incidence of Alzheimer's disease (AD) in the United States, overall and by geographic region.

DESIGN

We conducted retrospective analyses of administrative claims data for a 5% random sample of US Medicare beneficiaries aged 65 years or older. AD incidence, defined as a diagnosis for AD (International Classification of Disease, Ninth Revision, Clinical Modification code 331.0×) in a given year, with no AD diagnosis in the beneficiary's entire medical history, was estimated for each calendar year between 2007 and 2014. Beneficiaries were required to be enrolled in Medicare for the calendar year of evaluation as well as the preceding 12 months. In addition, a cross-sectional assessment of geographic variation in AD incidence was conducted for 2014. For each population area (specifically, core-based statistical area, as defined by the US Census Bureau), AD incidence was estimated overall, as well as adjusted for differences in underlying patient demographics and metrics of access to care and quality of care. Changes in AD incidence from 2007 were also estimated.

SETTING

US fee-for-service Medicare.

PARTICIPANTS

US Medicare beneficiaries aged 65 years or older with no history of AD.

RESULTS

Overall, the diagnosed incidence of AD decreased over time, from 1.53% in 2007 to 1.09% in 2014; trends were similar for most population areas. In 2014, the rates of AD incidence ranged from 0% to more than 3% across population areas, with the highest observed incidence rates in areas of the Midwest and the South. Statistical models explain little of the geographic variation, although following adjustment, the incidence rates increased the most (in relative terms) in rural areas of western states.

CONCLUSION

Our findings are consistent with previously reported estimates of incidence of AD in the United States and its recent declining trend. Additionally, the study highlights the considerable geographic variation in the incidence of AD in the United States and suggests that further research is needed to better understand the determinants of this geographic variation. J Am Geriatr Soc 68:346-353, 2020.

Prevalence of Biologically vs Clinically Defined Alzheimer Spectrum Entities Using the National Institute on Aging-Alzheimer's Association Research Framework

Importance

A National Institute on Aging-Alzheimer's Association (NIA-AA) workgroup recently published a research framework in which Alzheimer disease is defined by neuropathologic or biomarker evidence of β-amyloid plaques and tau tangles and not by clinical symptoms.

Objectives

To estimate the sex- and age-specific prevalence of 3 imaging biomarker-based definitions of the Alzheimer disease spectrum from the NIA-AA research framework and to compare these entities with clinically defined diagnostic entities commonly linked with Alzheimer disease.

Design, Setting, and Participants

The Mayo Clinic Study of Aging (MCSA) is a population-based cohort study of cognitive aging in Olmsted County, Minnesota. The MCSA in-person participants (n = 4660) and passively ascertained (ie, through the medical record rather than in-person) individuals with dementia (n = 553) aged 60 to 89 years were included. Subsets underwent amyloid positron emission tomography (PET) (n = 1524) or both amyloid and tau PET (n = 576). Therefore, this study included 3 nested cohorts examined between November 29, 2004, and June 5, 2018. Data were analyzed between February 19, 2018, and March 26, 2019.

Main Outcomes and Measures

The sex- and age-specific prevalence of the following 3 biologically defined diagnostic entities was estimated: Alzheimer continuum (abnormal amyloid regardless of tau status), Alzheimer pathologic change (abnormal amyloid but normal tau), and Alzheimer disease (abnormal amyloid and tau). These were compared with the prevalence of 3 clinically defined diagnostic groups (mild cognitive impairment or dementia, dementia, and clinically defined probable Alzheimer disease).

Results

The median (interquartile range) age was 77 (72-83) years in the clinical cohort (n = 5213 participants), 77 (70-83) years in the amyloid PET cohort (n = 1524 participants), and 77 (69-83) years in the tau PET cohort (n = 576 participants). There were roughly equal numbers of women and men. The prevalence of all diagnostic entities (biological and clinical) increased rapidly with age, with the exception of Alzheimer pathologic change. The prevalence of biological Alzheimer disease was greater than clinically defined probable Alzheimer disease for women and men. Among women, these values were 10% (95% CI, 6%-14%) vs 1% (95% CI, 1%-1%) at age 70 years and 33% (95% CI, 25%-41%) vs 10% (95% CI, 9%-12%) at age 85 years (P < .001). Among men, these values were 9% (95% CI, 5%-12%) vs 1% (95% CI, 0%-1%) at age 70 years and 31% (95% CI, 24%-38%) vs 9% (95% CI, 8%-11%) at age 85 years (P < .001). The only notable difference by sex was a greater prevalence of the mild cognitive impairment or dementia clinical category among men than women.

Conclusions and Relevance

Results of this study suggest that biologically defined Alzheimer disease is more prevalent than clinically defined probable Alzheimer disease at any age and is 3 times more prevalent at age 85 years among both women and men. This difference is mostly driven by asymptomatic individuals with biological Alzheimer disease. These findings illustrate the magnitude of the consequences on public health that potentially exist by intervening with disease-specific treatments to prevent symptom onset.

Prevalence of Cognitive Impairment and Association With Survival Among Older Patients With Hematologic Cancers

Importance

As the population ages, cognitive impairment has promised to become increasingly common among patients with cancer. Little is known about how specific domains of cognitive impairment may be associated with survival among older patients with hematologic cancers.

Objective

To determine the prevalence of domain-specific cognitive impairment and its association with overall survival among older patients with blood cancer.

Design, Setting, and Participants

This prospective observational cohort study included all patients 75 years and older who presented for initial consultation in the leukemia, myeloma, or lymphoma clinics of a large tertiary hospital in Boston, Massachusetts, from February 1, 2015, to March 31, 2017. Patients underwent screening for frailty and cognitive dysfunction and were followed up for survival.

Exposures

The Clock-in-the-Box (CIB) test was used to screen for executive dysfunction. A 5-word delayed recall test was used to screen for impairment in working memory. The Fried frailty phenotype and Rockwood cumulative deficit model of frailty were also assessed to characterize participants as robust, prefrail, or frail.

Results

Among 420 consecutive patients approached, 360 (85.7%) agreed to undergo frailty assessment (232 men [64.4%] and 128 women [35.6%]; mean [SD] age, 79.8 [3.9] years), and 341 of those (94.7%) completed both cognitive screening tests. One hundred twenty-seven patients (35.3%) had probable executive dysfunction on the CIB, and 62 (17.2%) had probable impairment in working memory on the 5-word delayed recall. Impairment in either domain was modestly correlated with the Fried frailty phenotype (CIB, ρ = 0.177; delayed recall, ρ = 0.170; P = .01 for both), and many phenotypically robust patients also had probable cognitive impairment (24 of 104 [23.1%] on CIB and 9 of 104 [8.7%] on delayed recall). Patients with impaired working memory had worse median survival (10.9 [SD, 12.9] vs 12.2 [SD, 14.7] months; log-rank P < .001), including when stratified by indolent cancer (log-rank P = .01) and aggressive cancer (P < .001) and in multivariate analysis when adjusting for age, comorbidities, and disease aggressiveness (odds ratio, 0.26; 95% CI, 0.13-0.50). Impaired working memory was also associated with worse survival for those undergoing intensive treatment (log-rank P < .001). Executive dysfunction was associated with worse survival only among patients who underwent intensive treatment (log-rank P = .03).

Conclusions and Relevance

These data suggest that domains of cognitive dysfunction may be prevalent in older patients with blood cancer and may have differential predictive value for survival. Targeted interventions are needed for this vulnerable patient population.

The Impact of Changes in Population Health and Mortality on Future Prevalence of Alzheimer's Disease and Other Dementias in the United States

Objectives

We assessed potential benefits for older Americans of reducing risk factors associated with dementia.

Methods

A dynamic simulation model tracked a national cohort of persons 51 and 52 years of age to project dementia onset and mortality in risk reduction scenarios for diabetes, hypertension, and dementia.

Results

We found reducing incidence of diabetes by 50% did not reduce number of years a person ages 51 or 52 lived with dementia and increased the population ages 65 and older in 2040 with dementia by about 115,000. Eliminating hypertension at middle and older ages increased life expectancy conditional on survival to age 65 by almost 1 year, however, it increased years living with dementia. Innovation in treatments that delay onset of dementia by 2 years increased longevity, reduced years with dementia, and decreased the population ages 65 and older in 2040 with dementia by 2.2 million.

Conclusions

Prevention of chronic disease may generate health and longevity benefits but does not reduce burden of dementia. A focus on treatments that provide even short delays in onset of dementia can have immediate impacts on longevity and quality of life and reduce the number of Americans with dementia over the next decades.

Short-Term Changes in the Prevalence of Probable Dementia: An Analysis of the 2011-2015 National Health and Aging Trends Study

Objectives

Studies have reported decreasing dementia prevalence in recent decades in the United States. We explore with a new national data source whether declines have occurred since 2011, whether trends are attributable to shifts in dementia incidence or mortality, and whether trends are related to shifts in population composition or subgroup prevalence.

Methods

We use the 2011-2015 National Health and Aging Trends Study (N = 27,547) to examine prevalence of probable dementia among the 70 and older population. To minimize the influence of potential learning effects on prevalence rates, we require individuals to meet probable dementia criteria at two consecutive rounds.

Results

Prevalence of probable dementia declines over this period by 1.4% to 2.6% per year. Declines are concentrated among women, non-Hispanic white and black groups, and those with no vascular conditions or risk factors. The latter group also has experienced declines in dementia incidence. Declines in prevalence are largely attributable to age- and education-related shifts in population composition.

Discussion

Given the role of age and educational composition in short-term declines, the United States is likely to continue to experience short-term declines in dementia prevalence. However, persistently high rates among minority groups, especially of Hispanic origin, are concerning, and, barring new treatments, long-run trends may reverse course.

Pre-Clinical Safety and Efficacy Evaluation of Amytrap, a Novel Therapeutic to Treat Alzheimer's Disease

Alzheimer’s disease (AD) is the most common cause of dementia. Amyloid-β (Aβ₄₂) is implicated in AD pathogenesis. We have designed a non-immune based proprietary therapeutic, called Amytrap, a conjugate containing a retro-inverso peptide, polyethylene glycol, and human serum albumin. Amytrap not only binds Aβ₄₂ but also prevents and dissociates aggregated Aβ₄₂. Amytrap binds to the region in Aβ₄₂ known to trigger its self-aggregation, thus disrupting aggregation. We have obtained proof of concept on AmyTrap in a clinically relevant mouse model, namely, AD-APPSWE/Tg2576. We synthesized and characterized Amytrap and confirmed its authenticity. Efficacy evaluations were performed on young (5 months) and old (9 months) model mice. Amytrap was injected biweekly for a period of five months. Pharmacokinetics and safety toxicology were assessed in normal mice and rats, respectively. Post treatment, younger mice showed significant improvements in cognition and Aβ₄₂ levels in plasma, brain, and cerebrospinal fluid, while older mice showed less significant benefits. Immunohistochemistry of brain sections showed similar differences between young and old mice. They all had diminished size and number of plaques in the brain of Amytrap-treated mice. Further, treated mice did not develop antibodies to Amytrap, suggesting Amytrap is non-immunogenic. Safety toxicological studies in rats showed that Amytrap was well tolerated and therefore safe (even at 50 X the efficacy dose). Stability tests showed Amytrap is stable at 4°C for up to one year. Efficacy and safety features make Amytrap a promising candidate for treating or modulating AD.

'Amytrapper', a Novel Immobilized Sepharose API Matrix, Removes Amyloid-β from Circulation in vitro

Alzheimer's disease (AD) is the most common cause of dementia among elderly patients afflicted by neurodegenerative diseases, caused by the accumulation of amyloid-β (Aβ). Therapeutic interventions in targeting and restricting Aβ production resulted in little or no success. However, recent studies have shown signs of success in validating Aβ as a target. Recombinant Technologies LLC (RTL) has developed and studied its proprietary Amytrap peptide to remove Aβ from circulation which in turn depletes brain Aβ in a clinically relevant mouse model of AD. In the current study, this Amytrap peptide (the active pharmacological ingredient, API) has been linked to sepharose matrix by click chemistry. The derivative namely 'Amytrapper' was confirmed to remove Aβ from the surrounding media spiked with Aβ₄₂. Additional testing performed on Amytrapper with sera and plasma containing Aβ₄₂ showed retention of Aβ₄₂ upon increasing concentrations of biotinylated Aβ₄₂ (bio-Aβ₄₂). Specificity of this binding was confirmed via 1) pre-blocking Amytrapper with cold (unbiotinylated) Aβ₄₂ followed by binding experiment with biotinylated Aβ₄₂, 2) 2-dimensional SDS-PAGE analyses on samples harvested before and after the binding experiment, and 3) reconciling the amounts bound to beads and left over in the flow through. The results provide a proof of concept for our proposed prototype design for an Amytrapper device. The results suggest that extracorporeal clearance of Aβ₄₂ by Amytrapper could be a way to manage accumulation of amyloid in AD and thus could become an added mode of therapy for disease modification.

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.

Soluble LR11 competes with amyloid β in binding to cerebrospinal fluid-high-density lipoprotein

BACKGROUND

LR11 is a member of the low-density lipoprotein (LDL) receptor family with high expression in neurons. Some cell surface LR11 is cleaved and secreted into the cerebrospinal fluid (CSF) as soluble LR11 (sLR11). Patients with Alzheimer's disease (AD), particularly apolipoprotein E4 carriers, have high CSF-sLR11 and low CSF-amyloid β (Aβ) concentrations. Therefore, we assessed whether sLR11 is bound to CSF-high-density lipoprotein (HDL) and whether sLR11 competes with Aβ in binding to apoE in CSF-HDL.

METHODS

We measured CSF-sLR11 concentrations (50 controls and 16 patients with AD) using enzyme immunoassay. sLR11 and apoE distribution in the CSF was evaluated using non-denaturing two-dimensional gel electrophoresis (N-2DGE). ApoE bound to sLR11 or Aβ was identified using co-immunoprecipitation assay.

RESULTS

CSF-sLR11 concentrations were higher in patients with AD than controls (adjusted for sLR11 using phospholipid). N-2DGE analysis showed that sLR11 and Aβ comigrated with a large apoE-containing CSF-HDL. Moreover, fewer apoE was bound to Aβ when a higher amount of apoE was bound to sLR11 in patients with AD who presented with ε4/4.

CONCLUSION

sLR11 binds to CSF-HDL and competes with Aβ in binding to apoE in CSF-HDL, indicating that sLR11 affects Aβ clearance via CSF-HDL.

A Common DIO2 Polymorphism and Alzheimer Disease Dementia in African and European Americans

Context

A common single nucleotide polymorphism in DIO2, Thr92AlaD2, has been associated with a transcriptome typically found in neurodegenerative diseases in postmortem human brain tissue.

Objective

To determine whether Thr92AlaD2 is associated with incident Alzheimer disease (AD).

Design

Population-based study; human brain tissue microarray.

Setting

Community-based cohorts from Chicago and northeastern Illinois and religious clergymen from across the United States constituted the primary population. A representative sample of the U.S. population was used for secondary analyses.

Participants

3054 African Americans (AAs) and 9304 European Americans (EAs).

Main Outcome Measure

Incident AD.

Results

In the primary population, AAs with Thr92AlaD2 had 1.3 times [95% confidence interval (CI), 1.02 to 1.68; P = 0.048] greater odds of developing AD. AAs from a second population with Thr92AlaD2 showed a trend toward increased odds of dementia (odds ratio, 1.33; 95% CI, 0.99 to 1.78; P = 0.06) and 1.35 times greater odds of developing cognitive impairment not demented (CIND; 95% CI, 1.09 to 1.67; P = 0.006). Meta-analysis showed that AAs with Thr92AlaD2 had 1.3 times increased odds of developing AD/dementia (95% CI, 1.07 to 1.58; P = 0.008). In EAs, no association was found between Thr92AlaD2 and AD, dementia, or CIND. Microarray of AA brain tissue identified transcriptional patterns linked to AD pathogenesis.

Conclusions

Thr92AlaD2 was associated with molecular markers known to underlie AD pathogenesis in AAs, translating to an observed phenotype of increased odds of developing AD/dementia in AAs in these populations. Thr92AlaD2 might represent one factor contributing to racial discrepancies in incident AD.

Secondary Analysis of Existing Datasets for Dementia and Palliative Care Research: High-Value Applications and Key Considerations

OBJECTIVE

To provide a guide to researchers selecting a dataset pertinent to the study of palliative care for people with dementia and to aid readers who seek to critically evaluate a secondary analysis study in this domain.

BACKGROUND

The impact of dementia at end-of-life is large and growing. Secondary dataset analysis can play a critical role in advancing research on palliative care for people with dementia.

METHODS

We conducted a broad search of a variety of resources to: 1. identity datasets that include information germane to dementia and palliative care research; 2. review relevant applications of secondary dataset analysis in the published literature; and 3. explore potential validity and reliability concerns.

RESULTS

We synthesize findings regarding: 1. Methodological approaches for determining the presence of dementia; 2. Inclusion and measurement of key palliative care items as they relate to people with dementia; and 3. Sampling and study design issues, including the role and implications of proxy-respondents. We describe and compare a selection of high-value existing datasets relevant to palliative care and dementia research.

DISCUSSION

While secondary analysis of existing datasets requires consideration of key limitations, it can be a powerful tool for efficiently enhancing knowledge of palliative care needs among people with dementia.

A classification algorithm for predicting progression from normal cognition to mild cognitive impairment across five cohorts: The preclinical AD consortium

INTRODUCTION

We established a method for diagnostic harmonization across multiple studies of preclinical Alzheimer's disease and validated the method by examining its relationship with clinical status and cognition.

METHODS

Cognitive and clinical data were used from five studies (N = 1746). Consensus diagnoses established in each study used criteria to identify progressors from normal cognition to mild cognitive impairment. Correspondence was evaluated between these consensus diagnoses and three algorithmic classifications based on (1) objective cognitive impairment in 2+ tests only; (2) a Clinical Dementia Rating (CDR) of ≥0.5 only; and (3) both. Associations between baseline cognitive performance and cognitive change were each tested in relation to progression to algorithm-based classifications.

RESULTS

In each study, an algorithmic classification based on both cognitive testing cutoff scores and a CDR ≥0.5 provided optimal balance of sensitivity and specificity (areas under the curve: 0.85-0.95). Over an average 6.6 years of follow-up (up to 28 years), N = 186 initially cognitively normal participants aged on average 64 years at baseline progressed (incidence rate: 15.3 people/1000 person-years). Baseline cognitive scores and cognitive change were associated with future diagnostic status using this algorithmic classification.

DISCUSSION

Both cognitive tests and CDR ratings can be combined across multiple studies to obtain a reliable algorithmic classification with high specificity and sensitivity. This approach may be applicable to large cohort studies and to clinical trials focused on preclinical Alzheimer's disease because it provides an alternative to implementation of a time-consuming adjudication panel.

Alzheimer's disease: The next frontier-Special Report 2017

In the history of medicine, one means to progress is when we make the decision that our assumptions and definitions of disease are no longer consistent with the scientific evidence, and no longer serve our health care needs. The arc of scientific progress is now requiring a change in how we diagnose Alzheimer's disease. Both the National Institute on Aging-Alzheimer's Association (NIA-AA) 2011 workgroup and the International Work Group (IWG) have proposed guidelines that use detectable measures of biological changes in the brain, commonly known as biological markers, or biomarkers, as part of the diagnosis. This Special Report examines how the development and validation of Alzheimer's disease biomarkers-including those detectable in the blood or cerebral spinal fluid, or through neuroimaging-is a top research priority. This has the potential to markedly change how we diagnose Alzheimer's disease and, as a result, how we count the number of people with this disease. As research advances a biomarker-based method for diagnosis and treatment at the earliest stages of Alzheimer's disease, we envision a future in which Alzheimer's disease is placed in the same category as other chronic diseases, such as cardiovascular disease or diabetes, which can be readily identified with biomarkers and treated before irrevocable disability occurs.

The Prevalence and Incidence of Dementia Due to Alzheimer's Disease: a Systematic Review and Meta-Analysis

BACKGROUND

Updated information on the epidemiology of dementia due to Alzheimer's disease (AD) is needed to ensure that adequate resources are available to meet current and future healthcare needs. We conducted a systematic review and meta-analysis of the incidence and prevalence of AD.

METHODS

The MEDLINE and EMBASE databases were searched from 1985 to 2012, as well as the reference lists of selected articles. Included articles had to provide an original population-based estimate for the incidence and/or prevalence of AD. Two individuals independently performed abstract and full-text reviews, data extraction and quality assessments. Random-effects models were employed to generate pooled estimates stratified by age, sex, diagnostic criteria, location (i.e., continent) and time (i.e., when the study was done).

RESULTS

Of 16,066 abstracts screened, 707 articles were selected for full-text review. A total of 119 studies met the inclusion criteria. In community settings, the overall point prevalence of dementia due to AD among individuals 60+ was 40.2 per 1000 persons (CI95%: 29.1-55.6), and pooled annual period prevalence was 30.4 per 1000 persons (CI95%: 15.6-59.1). In community settings, the overall pooled annual incidence proportion of dementia due to AD among individuals 60+ was 34.1 per 1000 persons (CI95%: 16.4-70.9), and the incidence rate was 15.8 per 1000 person-years (CI95%: 12.9-19.4). Estimates varied significantly with age, diagnostic criteria used and location (i.e., continent).

CONCLUSIONS

The burden of AD dementia is substantial. Significant gaps in our understanding of its epidemiology were identified, even in a high-income country such as Canada. Future studies should assess the impact of using such newer clinical diagnostic criteria for AD dementia such as those of the National Institute on Aging-Alzheimer's Association and/or incorporate validated biomarkers to confirm the presence of Alzheimer pathology to produce more precise estimates of the global burden of AD.

2016 Alzheimer's disease facts and figures

This report describes the public health impact of Alzheimer's disease, including incidence and prevalence, mortality rates, costs of care, and the overall impact on caregivers and society. It also examines in detail the financial impact of Alzheimer's on families, including annual costs to families and the difficult decisions families must often make to pay those costs. An estimated 5.4 million Americans have Alzheimer's disease. By mid-century, the number of people living with Alzheimer's disease in the United States is projected to grow to 13.8 million, fueled in large part by the aging baby boom generation. Today, someone in the country develops Alzheimer's disease every 66 seconds. By 2050, one new case of Alzheimer's is expected to develop every 33 seconds, resulting in nearly 1 million new cases per year. In 2013, official death certificates recorded 84,767 deaths from Alzheimer's disease, making it the sixth leading cause of death in the United States and the fifth leading cause of death in Americans age ≥ 65 years. Between 2000 and 2013, deaths resulting from stroke, heart disease, and prostate cancer decreased 23%, 14%, and 11%, respectively, whereas deaths from Alzheimer's disease increased 71%. The actual number of deaths to which Alzheimer's disease contributes is likely much larger than the number of deaths from Alzheimer's disease recorded on death certificates. In 2016, an estimated 700,000 Americans age ≥ 65 years will die with Alzheimer's disease, and many of them will die because of the complications caused by Alzheimer's disease. In 2015, more than 15 million family members and other unpaid caregivers provided an estimated 18.1 billion hours of care to people with Alzheimer's and other dementias, a contribution valued at more than $221 billion. Average per-person Medicare payments for services to beneficiaries age ≥ 65 years with Alzheimer's disease and other dementias are more than two and a half times as great as payments for all beneficiaries without these conditions, and Medicaid payments are 19 times as great. Total payments in 2016 for health care, long-term care and hospice services for people age ≥ 65 years with dementia are estimated to be $236 billion. The costs of Alzheimer's care may place a substantial financial burden on families, who often have to take money out of their retirement savings, cut back on buying food, and reduce their own trips to the doctor. In addition, many family members incorrectly believe that Medicare pays for nursing home care and other types of long-term care. Such findings highlight the need for solutions to prevent dementia-related costs from jeopardizing the health and financial security of the families of people with Alzheimer's and other dementias.

Exposure to air pollution as a potential contributor to cognitive function, cognitive decline, brain imaging, and dementia: A systematic review of epidemiologic research

BACKGROUND

Dementia is a devastating condition typically preceded by a long prodromal phase characterized by accumulation of neuropathology and accelerated cognitive decline. A growing number of epidemiologic studies have explored the relation between air pollution exposure and dementia-related outcomes.

METHODS

We undertook a systematic review, including quality assessment, to interpret the collective findings and describe methodological challenges that may limit study validity. Articles, which were identified according to a registered protocol, had to quantify the association of an air pollution exposure with cognitive function, cognitive decline, a dementia-related neuroimaging feature, or dementia.

RESULTS

We identified 18 eligible published articles. The quality of most studies was adequate to exemplary. Almost all reported an adverse association between at least one pollutant and one dementia-related outcome. However, relatively few studies considered outcomes that provide the strongest evidence for a causal effect, such as within-person cognitive or pathologic changes. Reassuringly, differential selection would likely bias toward a protective association in most studies, making it unlikely to account for observed adverse associations. Likewise, using a formal sensitivity analysis, we found that unmeasured confounding is also unlikely to explain reported adverse associations.

DISCUSSION

We also identified several common challenges. First, most studies of incident dementia identified cases from health system records. As dementia in the community is underdiagnosed, this could generate either non-differential or differential misclassification bias. Second, almost all studies used recent air pollution exposures as surrogate measures of long-term exposure. Although this approach may be reasonable if the measured and etiologic exposure windows are separated by a few years, its validity is unknown over longer intervals. Third, comparing the magnitude of associations may not clearly pinpoint which, if any, pollutants are the probable causal agents, because the degree of exposure misclassification differs across pollutants. The epidemiologic evidence, alongside evidence from other lines of research, provides support for a relation of air pollution exposure to dementia. Future studies with improved design, analysis and reporting would fill key evidentiary gaps and provide a solid foundation for recommendations and possible interventions.

Is Vasomotion in Cerebral Arteries Impaired in Alzheimer's Disease?

A substantial body of evidence supports the hypothesis of a vascular component in the pathogenesis of Alzheimer’s disease (AD). Cerebral hypoperfusion and blood-brain barrier dysfunction have been indicated as key elements of this pathway. Cerebral amyloid angiopathy (CAA) is a cerebrovascular disorder, frequent in AD, characterized by the accumulation of amyloid-β (Aβ) peptide in cerebral blood vessel walls. CAA is associated with loss of vascular integrity, resulting in impaired regulation of cerebral circulation, and increased susceptibility to cerebral ischemia, microhemorrhages, and white matter damage. Vasomotion— the spontaneous rhythmic modulation of arterial diameter, typically observed in arteries/arterioles in various vascular beds including the brain— is thought to participate in tissue perfusion and oxygen delivery regulation. Vasomotion is impaired in adverse conditions such as hypoperfusion and hypoxia. The perivascular and glymphatic pathways of Aβ clearance are thought to be driven by the systolic pulse. Vasomotion produces diameter changes of comparable amplitude, however at lower rates, and could contribute to these mechanisms of Aβ clearance. In spite of potential clinical interest, studies addressing cerebral vasomotion in the context of AD/CAA are limited. This study reviews the current literature on vasomotion, and hypothesizes potential paths implicating impaired cerebral vasomotion in AD/CAA. Aβ and oxidative stress cause vascular tone dysregulation through direct effects on vascular cells, and indirect effects mediated by impaired neurovascular coupling. Vascular tone dysregulation is further aggravated by cholinergic deficit and results in depressed cerebrovascular reactivity and (possibly) impaired vasomotion, aggravating regional hypoperfusion and promoting further Aβ and oxidative stress accumulation.

Treatment Patterns with Antidementia Drugs in the United States: Medicare Cohort Study

OBJECTIVES

To evaluate frequency of use of two anti-dementia drug classes approved for treatment of symptoms, whether populations most likely to benefit are treated, and correlates of treatment initiation.

DESIGN

Nationally representative cohort study.

SETTING

Fee-for-service Medicare.

PARTICIPANTS

Elderly adults with dementia enrolled in Medicare Parts A, B, and D in 2009 (N = 433,559) and a subset with incident dementia (n = 185,449).

MEASUREMENTS

Main outcome was any prescription fill for antidementia drugs (cholinesterase inhibitors (ChEIs) or memantine) within 1 year.

RESULTS

Treatment with antidementia drugs occurred in 55.8% of all participants with dementia and 49.3% of those with incident dementia. There was no difference between ChEIs and memantine use according to dementia severity (measured as death within first year or living in residential care vs in a community setting) even though memantine is not indicated in mild disease. In incident cases, initiation of treatment was lower in residential care (relative risk (RR) = 0.82, 95% confidence interval (CI) = 0.81-0.83) and with more comorbidities (RR = 0.96, 95% CI = 0.96-0.96). Sixty percent of participants were managed in primary care alone. Seeing a neurologist (RR = 1.07, 95% CI = 1.06-1.09) or psychiatrist (RR = 1.17, 95% CI = 1.16-1.19) was associated with higher likelihood of treatment than seeing a primary care provider alone, and seeing geriatrician was associated with with lower likelihood (RR = 0.96, 95% CI = 0.93-0.99). Across the United States, the proportion of newly diagnosed individuals started on antidementia treatment varied from 32% to 66% across hospital referral regions.

CONCLUSION

Antidementia drugs are used less often in people with late disease, but there is no differentiation in medication choice. Although primary care providers most often prescribe antidementia medication without specialty support, differences in practice between specialties are evident.