Change in risk of Alzheimer disease over time

Risk Factors and Neuropsychological Assessments of Subjective Cognitive Decline (plus) in Chinese Memory Clinic

Background

Since subjective cognitive decline (SCD) was standardized in 2014, many studies have investigated its features. However, the risk of SCD (plus) progressing to AD is much higher, and yet there have been few studies reporting the risk factors and neuropsychological assessment characteristics of SCD (plus).

Objective

To characterize SCD (plus) by comparing it with normal control (NC), amnesic mild cognitive impairment (aMCI), and Alzheimer Disease (AD) regarding their demographics, lifestyle, family history of dementia, multimorbidity and the neuropsychological assessments.

Methods

A total of 135 participants were recruited, including 23 NC, 30 SCD (plus), 45 aMCI and 37 AD. Descriptive statistics were provided. A logistic regression model was used to analyze the affecting factors of SCD (plus), and finally the Receiver Operating Characteristic (ROC) analysis was applied to distinguish between SCD (plus) and NC.

Results

(1) SCD (plus) group was younger than both the aMCI group and AD group. It consisted of more participants with mental work and higher body mass index (BMI) than the AD group. (2) Scores of Auditory Verbal Learning Test - Immediate recall (AVLT-IR) and AVLT-Long delayed recall (AVLT-LR) decreased in the following order: NC→SCD (plus)→aMCI→AD. (3) The Area Under Curve (AUC) for discriminating SCD (plus) and NC group was from 0.673 to 0.838.

Conclusion

Aging is an important risk factor of both NC progressing to SCD (plus), and SCD (plus) progressing to aMCI or AD. In addition to aging, lower education level and lower BMI were significantly associated with greater odds of SCD (plus) progressing to aMCI or AD patients, whereas mental work was a protective factor of SCD (plus) progressing to AD. Finally, AVLT is a sensitive indicator of the cognitive decline and impairment in SCD (plus) in relative to normal controls.

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.

Perspectives of African American Older Adults on Brain Health: "Brains Get Tired Too"

BACKGROUND

Statistics suggest that African Americans have a disproportionately high prevalence of Alzheimer disease (AD), yet are less likely to enroll in AD clinical trials than white individuals. Although research has previously identified various barriers to participation, relatively little is known about how to overcome these barriers and engage African American individuals in AD research. The purpose of this study is to better understand how African Americans conceptualize brain health and their ability to influence healthy brain aging.

METHODS

Three African American community advocates each facilitated a small group of African American participants over 8 to 10 sessions of a photovoice process involving discussion and sharing of images focused on brain health. Sessions were audiotaped and transcribed verbatim and photographs were uploaded.

FINDINGS

Participants recognized a diversity of what brain health can mean and indicated an interconnectedness between brain health and its influences. Key factors that were identified by group members as key to brain health included lifestyle factors, activity, and engagement and nature, resiliency, and positivity.

DISCUSSION

These emic insights into perceptions of brain health may represent important foci for targeted messaging strategies to promote brain health and research engagement within the African American population.

Temporal trends in cognitive function of older US adults associated with population changes in demographic and cardiovascular profiles

BACKGROUND

Recent estimates suggest that dementia incidence is decreasing in the US possibly due to better management of cardiovascular disease (CVD) risk factors, but these studies lack repeated cross-sectional assessment among a representative US sample. Our objective was to assess temporal trends in cognitive performance in relation to CVD risk factors among older National Health and Nutrition Examination Survey (NHANES) participants.

METHODS

We used repeated cross-sectional assessment of 5711 participants ≥60 years of age from four NHANES cycles: 1999-2000, 2001-2002, 2011-2012 and 2013-2014. Cognitive function was assessed during each cycle with the Digit Symbol Substitution Test (DSST). We estimated mean DSST score at each cycle and annual trend in DSST before and after adjustment for age, sex, race/ethnicity, education, smoking status, blood pressure, glucose status and body mass index.

RESULTS

DSST scores was significantly higher for 2011-2012 (difference: 6.7, 95% CI 4.4 to 9.0) and 2013-2014 (difference: 6.2, 95% CI 4.0 to 8.5), but not 2001-2002 (difference: 2.3, 95% CI -0.01 to 4.6) as compared with 1999-2000 before adjustment. We observed a linear trend for higher annual DSST score before adjustment (DSST/year: 0.44, 95% CI 0.31 to 0.57) and after adjustment for age, sex, race/ethnicity, educational attainment and CVD risk factors (DSST/year: 0.17, 95% CI 0.08 to 0.26). Educational attainment was most strongly associated with the attenuation in the trend in cognitive function (77% of trend attenuation and 20% of variance in DSST).

CONCLUSION

Cognitive function is improving over time for US adults aged ≥60 years. These improvements are strongly associated with greater educational attainment and irrespective of the changing US demographic and cardiovascular health profiles.

Exploring Disasters through the Eyes of Residential Nursing Home Caregivers

Using qualitative interviews, this research explores the experiences of residential nursing home caregivers in Fukushima, who provided support to elderly sufferers of Alzheimer's or other related forms of dementia during the 2011 Great East Japan Earthquake and Tsunami. Although the disaster vulnerability of care recipients such as the elderly, infirmed, disabled, and sufferers of dementia have been studied, their caregivers' disaster experiences, vulnerability and resilience have remained comparatively invisible and under-investigated. Their experiences suggest that coping with the disasters as caregivers was complex and unexpected, and it should not be misunderstood to imply that their resilience is predictable and expected.

Incidence of Dementia and Alzheimer Disease Over Time: A Meta-Analysis

BACKGROUND/OBJECTIVES

Population-based incidence estimates of dementia and Alzheimer disease (AD) provide important information for public health policy and resource allocation. We conducted a meta-analysis of published studies that reported age-specific incidence rates of dementia and AD to determine whether dementia and AD incidence rates are changing over time.

DESIGN

PubMed and MEDLINE were searched for publications through June 30, 2017, using key words "dementia", "Alzheimer", and "incidence." Inclusion criteria for the meta-analysis are: (1) population-based studies using personal interviews and direct examinations of the study subjects, (2) standardized clinical diagnosis criteria, (3) reporting age-specific incidence rates, (4) published in English, and (5) sample size of 500 or greater and length of follow-up of 2 years or greater. Mixed-effects models were used to determine the association between birth year and incidence rates.

MEASUREMENTS

Age-specific dementia/AD incidence rates and their standard errors reported in each study.

RESULTS

Thirty-eight articles with 53 cohorts on dementia incidence and 31 articles with 35 cohorts on AD incidence met the inclusion criteria. There were significant associations between later birth years and decreased dementia incidence rates in all three age groups (65-74, 75-84, and 85 years and older). There were no significant associations between birth year and AD incident rates in any of the three age groups. In particular, AD incidence rates reported from Western countries stayed steady in all age groups, while studies in non-Western countries showed significantly increased AD incidence rates for the 65 to 74 years age group (odds ratio = 2.78; P = .04), but a nonsignificant association for the 75 to 84 or 85 years and older groups.

CONCLUSION

Dementia incidence declined over the past four decades, but AD incidence did not decline. Further research, especially from non-Western countries, is needed to elucidate the mechanism underlying the trends in dementia and AD incidence over time.

Analysis of dementia in the US population using Medicare claims: Insights from linked survey and administrative claims data

Introduction

Medicare claims data may be a rich data source for tracking population dementia rates. Insufficient understanding of completeness of diagnosis, and for whom, limits their use.

Methods

We analyzed agreement in prevalent and incident dementia based on cognitive assessment from the Health and Retirement Study for persons with linked Medicare claims from 2000 to 2008 (N = 10,450 persons). Multinomial logistic regression identified sociodemographic factors associated with disagreement.

Results

Survey-based cognitive tests and claims-based dementia diagnosis yielded equal prevalence estimates, yet only half were identified by both measures. Race and education were associated with disagreement. Eighty-five percent of respondents with incident dementia measured by cognitive decline received a diagnosis or died within the study period, with lower odds among blacks and Hispanics than among whites.

Discussions

Claims data are valuable for tracking dementia in the US population and improve over time. Delayed diagnosis may underestimate rates within black and Hispanic populations.

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.

Gene-environment interactions in Alzheimer's disease: A potential path to precision medicine

Alzheimer's disease (AD) is the leading cause of dementia in the United States and afflicts >5.7 million Americans in 2018. Therapeutic options remain extremely limited to those that are symptom targeting, while no drugs have been approved for the modification or reversal of the disease itself. Risk factors for AD including aging, the female sex, as well as carrying an APOE4 genotype. These risk factors have been extensively examined in the literature, while less attention has been paid to modifiable risk factors, including lifestyle, and environmental risk factors such as exposures to air pollution and pesticides. This review highlights the most recent data on risk factors in AD and identifies gene by environment interactions that have been investigated. It also provides a suggested framework for a personalized therapeutic approach to AD, by combining genetic, environmental and lifestyle risk factors. Understanding modifiable risk factors and their interaction with non-modifiable factors (age, susceptibility alleles, and sex) is paramount for designing personalized therapeutic interventions.

Causes and Patterns of Dementia: An Update in the Era of Redefining Alzheimer's Disease

The burden of dementia continues to increase as the population ages, with no disease-modifying treatments available. However, dementia risk appears to be decreasing, and progress has been made in understanding its multifactorial etiology. The 2018 National Institute on Aging-Alzheimer's Association (NIA-AA) research framework for Alzheimer's disease (AD) defines AD as a biological process measured by brain pathology or biomarkers, spanning the cognitive spectrum from normality to dementia. This framework facilitates interventions in the asymptomatic space and accommodates knowledge that many additional pathologies (e.g., cerebrovascular) contribute to the Alzheimer's dementia syndrome. The framework has implications for how we think about risk factors for "AD": Many commonly accepted risk factors are not related to AD pathology and would no longer be considered risk factors for AD. They may instead be related to other pathologies or resilience to pathology. This review updates what is known about causes, risk factors, and changing patterns of dementia, addressing whether they are related to AD pathology/biomarkers, other pathologies, or resilience.

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.

Prevalence and incidence of clinically diagnosed Alzheimer's disease dementia from 1994 to 2012 in a population study

INTRODUCTION

The trends in prevalence and incidence of Alzheimer's disease (AD) dementia remain uncertain.

METHODS

A sample of 2794 participants with a clinical diagnosis for AD dementia were included.

RESULTS

The 2010 census standardized prevalence of AD dementia was 14.5% (95% CI = 13.7-15.3), and annual incidence was 2.3% (1.7-2.9). Both prevalence and incidence showed substantial variation over time, but no secular trends. The prevalence of AD dementia did not change significantly from 14.6% (95% CI = 13.0, 16.2) in 1994-1997 to 14.7% (95% CI = 13.2, 16.2) in 2010-2012 (P = .84). The annual incidence of AD dementia was 2.8% (95% CI = 2.2, 3.2) in 1998-2000 and 2.2% (95% CI = 1.6, 2.8) in 2004-2006 (P = .20) and remained steady in 2010-2012. The prevalence and incidence among African Americans were approximately twice than those among European Americans.

CONCLUSIONS

The prevalence and incidence of AD dementia showed substantial variation between 1994 and 2012, but no secular trend.

Vascular biomarkers and ApoE4 expression in mild cognitive impairment and Alzheimer's disease

Vascular pathology and genetic markers such as apolipoprotein E allele ε4 (ApoE ε4) are risk factors for the progression from mild cognitive impairment (MCI) to Alzheimer's disease (AD). In Panama, a high prevalence of vascular risk factors and an increase in the aging population, generate the need to investigate biomarkers using specific, sensitive, non-invasive and cost-efficient methods that could be used in primary care. The main objective of this study was to explore the association between vascular biomarkers such as intima-media thickness (IMT) and stenosis, ApoΕ ε4 and cognitive function in a sample of older adults, including healthy controls (n = 41), MCI (n = 33), and AD (n = 12). A descriptive and cross-sectional study was conducted. Participants were part of the Panama Aging Research Initiative (PARI), the first prospective study in aging in Panama. Assessments included a neuropsychological battery, ApoΕ ε4 genotyping and a Doppler ultrasound of the left carotid artery to examine the presence of vascular risk factors. Neuropsychological tests were combined to form six cognitive domains: Global cognition, language, visuospatial abilities, learning and memory, attention and executive functions. Multivariable analyses (using age, education, and ApoE ε4 expression as covariates) were conducted. Participants with increased IMT showed poorer performance in memory and those with carotid stenosis showed poorer performance in language, visuospatial abilities and attention, independent of age, education or ApoΕ ε4 expression. The results support the use of vascular markers in cognitive assessments of aged individuals.

Functional and structural connectome properties in the 5XFAD transgenic mouse model of Alzheimer's disease

Neurodegeneration in Alzheimer's disease (AD) is associated with amyloid-beta peptide accumulation into insoluble amyloid plaques. The five-familial AD (5XFAD) transgenic mouse model exhibits accelerated amyloid-beta deposition, neuronal dysfunction, and cognitive impairment. We aimed to determine whether connectome properties of these mice parallel those observed in patients with AD. We obtained diffusion tensor imaging and resting-state functional magnetic resonance imaging data for four transgenic and four nontransgenic male mice. We constructed both structural and functional connectomes and measured their topological properties by applying graph theoretical analysis. We compared connectome properties between groups using both binarized and weighted networks. Transgenic mice showed higher characteristic path length in weighted structural connectomes and functional connectomes at minimum density. Normalized clustering and modularity were lower in transgenic mice across the upper densities of the structural connectome. Transgenic mice also showed lower small-worldness index in higher structural connectome densities and in weighted structural networks. Hyper-correlation of structural and functional connectivity was observed in transgenic mice compared with nontransgenic controls. These preliminary findings suggest that 5XFAD mouse connectomes may provide useful models for investigating the molecular mechanisms of AD pathogenesis and testing the effectiveness of potential treatments.

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

BACKGROUND

Determination of secular trends in cognitive aging is important for prioritization of resources, services, and research in aging populations. Prior studies have identified declining dementia incidence associated with changes in cardiovascular risk factors and increased educational attainment. However, few studies have examined these factors in multi-ethnic cohorts.

OBJECTIVE

To identify secular trends in the incidence rate of dementia in an elderly population.

METHODS

Participants in this study were drawn from the Washington Heights-Inwood Columbia Aging Project, a multi-ethnic cohort study of northern Manhattan residents aged 65 years and older. Cox proportional hazards models were used to examine differences in the incidence of dementia in cohorts recruited in 1992 and 1999, with age at dementia or age at last follow-up visit as the "time-to-event" variable.

RESULTS

Overall, there was a 41% reduction in the hazard ratio for dementia among participants in the 1999 cohort compared with those in the 1992 cohort, adjusting for age, sex, race, and baseline memory complaints (HR = 0.59). The reduction in incidence was greatest among non-Hispanic Whites and African-Americans and lowest among Hispanic participants (HRs = 0.60, 0.52 and 0.64, respectively), and was associated with increases in level of educational attainment, especially among African-Americans. Reduction in incidence of dementia was also greater among persons 75 years or older than among younger participants (HR = 0.52 versus HR = 0.69).

CONCLUSIONS

Our results support previous findings that secular trends in dementia incidence are changing, including in aging minority populations.

Anesthesia and Alzheimer disease – Current perceptions

Background and objectives

It has been speculated that the use of anesthetic agents may be a risk factor for the development of Alzheimer disease. The objective of this review is to describe and discuss pre-clinical and clinical data related to anesthesia and this disease.

Content

Alzheimer disease affects about 5% of the population over 65 years old, with age being the main risk factor and being associated with a high morbidity. Current evidence questions a possible association between anesthesia, surgery, and long-term cognitive effects, including Alzheimer disease. Although data from some animal studies suggest an association between anesthesia and neurotoxicity, this link remains inconclusive in humans. We performed a review of the literature in which we selected scientific articles in the PubMed database, published between 2005 and 2016 (one article from 1998 due to its historical relevance), in English, which address the possible relationship between anesthesia and Alzheimer disease. 49 articles were selected.

Conclusion

The possible relationship between anesthetic agents, cognitive dysfunction, and Alzheimer disease remains to be clarified. Prospective cohort studies or randomized clinical trials for a better understanding of this association will be required.

The Effect of Adherence to Screening Guidelines on the Risk of Alzheimer's Disease in Elderly Individuals Newly Diagnosed With Type 2 Diabetes Mellitus

Objective: The aim of this study was to examine the possibility that type 2 diabetes and Alzheimer's disease may share common behavioral protective factors such as adherence to type 2 diabetes treatment guidelines given that these two diseases have both epidemiological and metabolic similarities. Method: The method used in this study is a retrospective cohort study of 3,797 U.S. Medicare fee-for-service beneficiaries aged 66+ newly diagnosed with type 2 diabetes and without a prior record of Alzheimer's disease based on the Health and Retirement Study. Results: Results of a left-truncated Cox model showed that adherence reduces the risk of Alzheimer's disease by 20% to 24%. Other significant effects were college education (hazard ratio [HR]: 0.65; p value: .023), stroke (HR: 1.40; p value: .013), and 4+ limitations in physical functioning (HR: 1.33; p value: .008). Discussion: Risk of Alzheimer's disease can be reduced by behavioral factors. Possible mechanisms may include earlier start of interventions to reduce blood glucose levels and improve insulin sensitivity.

Trends in Dementia Incidence in a Birth Cohort Analysis of the Einstein Aging Study

Importance

Trends in dementia incidence rates have important implications for planning and prevention. To better understand incidence trends over time requires separation of age and cohort effects, and few prior studies have used this approach.

Objectives

To examine trends in dementia incidence and concomitant trends in cardiovascular comorbidities among individuals aged 70 years or older who were enrolled in the Einstein Aging Study between 1993 and 2015.

Design, Setting, and Participants

In this birth cohort analysis of all-cause dementia incidence in persons enrolled in the Einstein Aging Study from October 20, 1993, through November 17, 2015, a systematically recruited, population-based sample of 1348 participants from Bronx County, New York, who were 70 years or older without dementia at enrollment and at least one annual follow-up was studied. Poisson regression was used to model dementia incidence as a function of age, sex, educational level, race, and birth cohort, with profile likelihood used to identify the timing of significant increases or decreases in incidence.

Exposures

Birth year and age.

Main Outcomes and Measures

Incident dementia defined by consensus case conference based on annual, standardized neuropsychological and neurologic examination findings, using criteria from the DSM-IV.

Results

Among 1348 individuals (mean [SD] baseline age, 78.5 [5.4] years; 830 [61.6%] female; 915 [67.9%] non-Hispanic white), 150 incident dementia cases developed during 5932 person-years (mean [SD] follow-up, 4.4 [3.4] years). Dementia incidence decreased in successive birth cohorts. Incidence per 100 person-years was 5.09 in birth cohorts before 1920, 3.11 in the 1920 through 1924 birth cohorts, 1.73 in the 1925 through 1929 birth cohorts, and 0.23 in cohorts born after 1929. Change point analyses identified a significant decrease in dementia incidence among those born after July 1929 (95% CI, June 1929 to January 1930). The relative rate for birth cohorts before July 1929 vs after was 0.13 (95% CI, 0.04-0.41). Prevalence of stroke and myocardial infarction decreased across successive birth cohorts, whereas diabetes prevalence increased. Adjustment for these cardiovascular comorbidities did not explain the decreased dementia incidence rates for more recent birth cohorts.

Conclusions and Relevance

Analyses confirm decreasing dementia incidence in this population-based sample. Whether decreasing incidence will contribute to reduced burden of dementia given the aging of the population is not known.

Aberrant DNA methylation associated with Alzheimer's disease in the superior temporal gyrus

Abnormal DNA methylation patterns have been demonstrated to be associated with the pathogenesis of Alzheimer's disease (AD). The present study aimed to identify differential methylation in the superior temporal gyrus (STG) of patients with late-onset AD based on epigenome-wide DNA methylation data by bioinformatics analysis. The genome-wide DNA methylation data in the STG region of 34 patients with late-onset AD and 34 controls without dementia were recruited from the Gene Expression Omnibus database. Through systemic quality control, differentially methylated CpG sites were determined by the Student's t-test and mean methylation value differences between the two conditions. Hierarchical clustering analysis was applied to assess the classification performance of differentially methylated CpGs. Functional analysis was performed to investigate the biological functions of the genes associated with differentially methylated CpGs. A total of 17,895 differentially methylated CpG sites were initially identified, including 11,822 hypermethylated CpGs and 6,073 hypomethylated CpGs. Further analysis examined 2,211 differentially methylated CpGs (covering 1,991 genes). AD subjects demonstrated distinctive DNA methylation patterns when compared with the controls, with a classification accuracy value of 1. Hypermethylation was mainly detected for genes regulating the cell cycle progression, whereas hypomethylation was observed in genes involved in transcription factor binding. The present study demonstrated widespread and distinctive DNA methylation alterations in late-onset AD. Identification of AD-associated epigenetic biomarkers may allow for the development of novel diagnostic and therapeutic targets.

Alzheimer's Disease in Social Media: Content Analysis of YouTube Videos

Background

Approximately 5.5 million Americans are living with Alzheimer’s disease (AD) in 2017. YouTube is a popular platform for disseminating health information; however, little is known about messages specifically regarding AD that are being communicated through YouTube.

Objective

This study aims to examine video characteristics, content, speaker characteristics, and mobilizing information (cues to action) of YouTube videos focused on AD.

Methods

Videos uploaded to YouTube from 2013 to 2015 were searched with the term “Alzheimer’s disease” on April 30th, 2016. Two coders viewed the videos and coded video characteristics (the date when a video was posted, Uniform Resource Locator, video length, audience engagement, format, author), content, speaker characteristics (sex, race, age), and mobilizing information. Descriptive statistics were used to examine video characteristics, content, audience engagement (number of views), speaker appearances in the video, and mobilizing information. Associations between variables were examined using Chi-square and Fisher’s exact tests.

Results

Among the 271 videos retrieved, 25.5% (69/271) were posted by nonprofit organizations or universities. Informal presentations comprised 25.8% (70/271) of all videos. Although AD symptoms (83/271, 30.6%), causes of AD (80/271, 29.5%), and treatment (76/271, 28.0%) were commonly addressed, quality of life of people with AD (34/271, 12.5%) had more views than those more commonly-covered content areas. Most videos featured white speakers (168/187, 89.8%) who were adults aged 20 years to their early 60s (164/187, 87.7%). Only 36.9% (100/271) of videos included mobilizing information. Videos about AD symptoms were significantly less likely to include mobilizing information compared to videos without AD symptoms (23/83, 27.7% vs 77/188, 41.0% respectively; P=.03).

Conclusions

This study contributes new knowledge regarding AD messages delivered through YouTube. Findings of the current study highlight a potential gap between available information and viewers’ interests. YouTube videos on AD could be beneficial if the messages delivered meet users’ needs and provide mobilizing information for further resources. Study findings will be useful to government agencies, researchers, nonprofit organizations that promote information about AD, and those responsible for social media to provide useful and accurate health information for the public.

Resveratrol for Alzheimer's disease

The amyloid hypothesis suggests that the progressive accumulation and deposition of central nervous system (CNS) amyloid with aging is the proximate cause of Alzheimer's disease (AD). Thus, targeting molecular mechanisms of aging may be a viable treatment approach. Caloric restriction prevents diseases of aging, including AD, in animal models, perhaps by activation of sirtuins. The sirtuins (e.g., mammalian SIRT1) are deacetylases that link energy balance (NAD⁺ /NADH) to regulation of gene transcription. Resveratrol is a potent activator of SIRT1, and thus may mimic caloric restriction to prevent diseases of aging. We conducted a randomized, double-blind, placebo-controlled, phase II trial of resveratrol for individuals with mild-to-moderate AD. Resveratrol (1) is detectable in cerebrospinal fluid (at low nanomolar levels), (2) is safe and well tolerated, (3) alters AD biomarker trajectories, (4) preserves blood-brain barrier integrity, and (5) modulates the CNS immune response. Further studies are needed to determine the safety and efficacy of resveratrol and the validity of this approach in the treatment and prevention of AD and other diseases of aging.

Decreasing prevalence of dementia in 85-year olds examined 22 years apart: the influence of education and stroke

Individuals aged 80 years and older constitute the fastest growing segment of the population worldwide, leading to an expected increase in dementia cases. Education level and treatment of vascular risk factors has increased during the last decades. We examined whether this has influenced the prevalence of dementia according to DSM-III-R using population-based samples of 85-year-olds (N = 1065) examined with identical methods 1986–87 and 2008–10. The prevalence of dementia was 29.8% in 1986–87 and 21.7% in 2008–10 (OR 0.66; 95%-CI: 0.50–0.86). The decline was mainly observed for vascular dementia. The proportion with more than basic education (25.2% and 57.7%), and the prevalence of stroke (20% and 30%) increased, but the odds ratio for dementia with stroke decreased from 4.3 to 1.8 (interaction stroke*birth cohort; p = 0.008). In a logistic regression, education (OR 0.70; 95%-CI 0.51–0.96), stroke (OR 3.78; 95%-CI 2.28–6.29), interaction stroke*birth cohort (OR 0.50; 95%-CI 0.26–0.97), but not birth cohort (OR 0.98; 95%-CI 0.68–1.41), were related to prevalence of dementia. Thus, the decline in dementia prevalence was mainly explained by higher education and lower odds for dementia with stroke in later born birth cohorts. The findings may be related to an increased cognitive reserve and better treatment of stroke in later-born cohorts.

The changing prevalence and incidence of dementia over time - current evidence

Dementia is an increasing focus for policymakers, civil organizations and multidisciplinary researchers. The most recent descriptive epidemiological research into dementia is enabling investigation into how the prevalence and incidence are changing over time. To establish clear trends, such comparisons need to be founded on population-based studies that use similar diagnostic and research methods consistently over time. This narrative Review synthesizes the findings from 14 studies that investigated trends in dementia prevalence (nine studies) and incidence (five studies) from Sweden, Spain, the UK, the Netherlands, France, the USA, Japan and Nigeria. Besides the Japanese study, these studies indicate stable or declining prevalence and incidence of dementia, and some provide evidence of sex-specific changes. No single risk or protective factor has been identified that fully explains the observed trends, but major societal changes and improvements in living conditions, education and healthcare might have favourably influenced physical, mental and cognitive health throughout an individual's life course, and could be responsible for a reduced risk of dementia in later life. Analytical epidemiological approaches combined with translational neuroscientific research could provide a unique opportunity to explore the neuropathology that underlies changing occurrence of dementia in the general population.

Trends in dementia prevalence, incidence, and survival rate in a Japanese community

OBJECTIVE

To investigate secular trends in the prevalence, incidence, and survival rate of dementia in a Japanese elderly population in a comprehensive manner.

METHODS

Five cross-sectional surveys of dementia were conducted among residents of a Japanese community, aged ≥65 years, in 1985, 1992, 1998, 2005, and 2012. We also established 2 cohorts consisting of the residents of this age group without dementia in 1988 (n = 803) and 2002 (n = 1,231), and each was followed for 10 years.

RESULTS

The age-standardized prevalence of all-cause dementia and Alzheimer disease (AD) increased with time (for all-cause dementia: 6.8% in 1985, 4.6% in 1992, 5.3% in 1998, 8.4% in 2005, and 11.3% in 2012, p for trend <0.01; for AD: 1.5%, 1.4%, 2.4%, 3.9%, and 7.2%, respectively, p for trend <0.01), while no secular change was observed for vascular dementia (VaD) (2.4%, 1.6%, 1.5%, 2.4%, and 2.4%, respectively, p for trend = 0.59). The age- and sex-adjusted incidence of all-cause dementia and AD, but not VaD, increased from the 1988 cohort to the 2002 cohort (for all-cause dementia: adjusted hazard ratio [aHR] 1.68, 95% confidence interval [CI] 1.38-2.06; for AD: aHR 2.07, 95% CI 1.59-2.70; for VaD: aHR 1.18, 95% CI 0.83-1.69). The 5-year survival rate of all-cause dementia and AD improved from the 1988 cohort to the 2002 cohort (for all-cause dementia: 47.3% to 65.2%; for AD: 50.7% to 75.1%; all p < 0.01).

CONCLUSIONS

The increased incidence and improved survival rate of AD could have resulted in the steep increase in AD prevalence in the Japanese elderly.

A critical evaluation of neuroprotective and neurodegenerative MicroRNAs in Alzheimer's disease

Currently, 5.4 million Americans suffer from AD, and these numbers are expected to increase up to 16 million by 2050. Despite tremendous research efforts, we still do not have drugs or agents that can delay, or prevent AD and its progression, and we still do not have early detectable biomarkers for AD. Multiple cellular changes have been implicated in AD, including synaptic damage, mitochondrial damage, production and accumulation of Aβ and phosphorylated tau, inflammatory response, deficits in neurotransmitters, deregulation of the cell cycle, and hormonal imbalance. Research into AD has revealed that miRNAs are involved in each of these cellular changes and interfere with gene regulation and translation. Recent discoveries in molecular biology have also revealed that microRNAs play a major role in post-translational regulation of gene expression. The purpose of this article is to review research that has assessed neuroprotective and neurodegenerative characteristics of microRNAs in brain samples from AD transgenic mouse models and patients with AD.

Impact of Physical Activity on Cognitive Decline, Dementia, and Its Subtypes: Meta-Analysis of Prospective Studies

The association of physical activity with dementia and its subtypes has remained controversial in the literature and has continued to be a subject of debate among researchers. A systematic review and meta-analysis of longitudinal studies on the relationship between physical activity and the risk of cognitive decline, all-cause dementia, Alzheimer's disease, and vascular dementia among nondemented subjects are considered. A comprehensive literature search in all available databases was conducted up until April 2016. Well-defined inclusion and exclusion criteria were developed with focus on prospective studies ≥ 12 months. The overall sample from all studies is 117410 with the highest follow-up of 28 years. The analyses are performed with both Bayesian parametric and nonparametric models. Our analysis reveals a protective effect for high physical activity on all-cause dementia, odds ratio of 0.79, 95% CI (0.69, 0.88), a higher and better protective effect for Alzheimer's disease, odds ratio of 0.62, 95% CI (0.49, 0.75), cognitive decline odds ratio of 0.67, 95% CI (0.55, 0.78), and a nonprotective effect for vascular dementia of 0.92, 95% CI (0.62, 1.30). Our findings suggest that physical activity is more protective against Alzheimer's disease than it is for all-cause dementia, vascular dementia, and cognitive decline.

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.