Brain aging: lessons from community studies

Urgent needs of caregiving in ageing populations with Alzheimer's disease and other chronic conditions: Support our loved ones

The ageing process begins at birth. It is a life-long process, and its exact origins are still unknown. Several hypotheses attempt to describe the normal ageing process, including hormonal imbalance, formation of reactive oxygen species, DNA methylation & DNA damage accumulation, loss of proteostasis, epigenetic alterations, mitochondrial dysfunction, senescence, inflammation, and stem cell depletion. With increased lifespan in elderly individuals, the prevalence of age-related diseases including, cancer, diabetes, obesity, hypertension, Alzheimer's, Alzheimer's disease and related dementias, Parkinson's, and other mental illnesses are increased. These increased age-related illnesses, put tremendous pressure & burden on caregivers, family members, and friends who are living with patients with age-related diseases. As medical needs evolve, the caregiver is expected to experience an increase in duties and challenges, which may result in stress on themselves, and impact their own family life. In the current article, we assess the biological mechanisms of ageing and its effect on body systems, exploring lifestyle and ageing, with a specific focus on age-related disorders. We also discussed the history of caregiving and specific challenges faced by caregivers in the presence of multiple comorbidities. We also assessed innovative approaches to funding caregiving, and efforts to improve the medical system to better organize chronic care efforts, while improving the skill and efficiency of both informal and formal caregivers. We also discussed the role of caregiving in end-of-life care. Our critical analysis strongly suggests that there is an urgent need for caregiving in aged populations and support from local, state, and federal agencies.

Development of dementia in patients who underwent bariatric surgery

BACKGROUND

Dementia, including Alzheimer's disease, interfere with daily function and are one of the major causes of disability, institutionalization, and death. Obesity is associated with an increased risk of dementia. However, the effect of significant and sustained weight loss following bariatric surgery on dementia is not known. The purpose of this study was to assess the long-term risk of dementia following bariatric surgery.

METHODS

A surgical cohort was identified from the Utah Bariatric Surgery Registry and was linked to the Utah Population Database that includes electronic medical records, death records, and State Facility data. Adult subjects (≥ 18 years old) at time of surgery (1996-2016) were matched with non-surgical subjects. The final sample included 51,078 subjects (1:2 matching); surgery group n = 17,026; non-surgery subjects n = 34,052). Dementia were identified by ICD-9/10 diagnosis codes following surgery year or matched baseline year. Cox proportional hazard model was used to calculate the hazard ratio in the outcome between the groups.

RESULTS

Average (SD) age of the subjects was 42 (12) years old at surgery or matched baseline year, 78% were female and mean follow-up time was 10.5 years. 1.4% of the surgery group and 0.5% of the control group had an incidence of dementia. Controlling the covariates in the Cox regression, the surgery group had a higher risk for dementia incidence than the matched non-surgery subjects (HR = 1.33, p = 0.02).

CONCLUSIONS

The study showed an increased hazard for dementia in individuals who underwent bariatric surgery compared to matched non-surgical subjects. Additional long-term data is needed to verify this association.

Association between physical activity and mild cognitive impairment in community-dwelling older adults: Depression as a mediator

Introduction

Dementia has become a public health priority and is irreversible. Mild cognitive impairment (MCI), an intermediate state between normal cognition and dementia, is the prime time for early diagnosis and intervention. The activities of daily living of dementia patients are usually insufficient. Therefore, continuing to explore the risk factors of MCI, especially the influence of physical activity on MCI and its mechanism can enrich the relevant research fields in China.

Materials and methods

For this cross-sectional study, 2,518 adults aged 60 years or older in Xinzhuang, Minhang District, Shanghai were recruited between July 2019 and April 2019, using a multistage, cluster-sampling method. A binary unconditional logistic regression model was used with MCI status as the dependent variable. Different types of physical activity were separately included in the multifactor model to test their correlations. Sensitivity analysis was performed using BADL as a stratification factor. The mediating effect of depression between physical activity and MCI was examined using the Bootstrap method.

Results

This research includes 271 (10.8%) MCI. Old age (odds ratio 2.967 [95%CI 2.063∼4.269]), having diabetes (1.816 [1.302∼2.534]), and depression (3.012 [2.209∼4.108]) were possible risk factors for MCI. High education level (0.722 [0.523∼0.999]), medium level of physical activity (0.459 [0.326∼0.645]), and high level of physical activity (0.396 [0.270∼0.580]) were possible protective factors. Medium (0.548 [0.396∼0.757]) and high levels (0.557 [0.366∼0.846]) of physical exercise and medium (0.433 [0.318∼0.590]) and high levels (0.487 [0.296∼0.801]) of household chores are possible protective factors of MCI and their significance remained in the mutually adjusted model. Sensitivity analysis showed that physical activity and household chores were possible protective factors in all strata (P < 0.05). Physical exercise and work-related activities showed a protective effect in fully independent older adults, but the effect disappeared in those who cannot be fully independent. Depression played a partially mediating role with an indirect effect of 6.67%.

Discussion

Overall, our results highlight that physical activity is a possible protective factor for MCI. Physical exercise and household chores have strong protective effects and future interventions could be targeted from this perspective. Depression plays a partially mediating role and more attention should be paid to the mental health of older adults.

Trajectory classes of social activity and their effects on longitudinal changes in cognitive function among older adults

OBJECTIVES

This study aimed to identify the social activity trajectory by class and the effects on the cognitive function trajectory among older adults.

METHODS

Data from six waves of the 2006-2016 Korean Longitudinal Study of Aging were analyzed. This study included 3,002 participants aged ≥65 years. Latent class growth modeling was used to classify the respondents based on their engagement in social activity over 10 years. Latent growth modeling was used to examine the effect of their social activity trajectory by class to predict participants' cognitive function trajectory.

RESULTS

We identified four social activity trajectory classes: high-stable (7.8%), moderate-stable (50.3%), high-decreasing (2.9%), and low-decreasing (39.0%). Older adults with an age of 75 years or older, a low education level, instrumental activities of daily living limitations, and depressive symptoms were more likely to be in the low-decreasing social activity trajectory class. The respondents in the high-stable (B = 0.680, p < 0.001) and moderate-stable (B = 0.362, p < 0.001) classes showed a slower rate of cognitive decline compared with those in the low-decreasing class.

DISCUSSION

Community-based strategies need to be developed to encourage older adults to maintain their social activity engagement and ultimately prevent cognitive decline.

Predicting dementia diagnosis from cognitive footprints in electronic health records: a case-control study protocol

INTRODUCTION

Dementia is a group of disabling disorders that can be devastating for persons living with it and for their families. Data-informed decision-making strategies to identify individuals at high risk of dementia are essential to facilitate large-scale prevention and early intervention. This population-based case-control study aims to develop and validate a clinical algorithm for predicting dementia diagnosis, based on the cognitive footprint in personal and medical history.

METHODS AND ANALYSIS

We will use territory-wide electronic health records from the Clinical Data Analysis and Reporting System (CDARS) in Hong Kong between 1 January 2001 and 31 December 2018. All individuals who were at least 65 years old by the end of 2018 will be identified from CDARS. A random sample of control individuals who did not receive any diagnosis of dementia will be matched with those who did receive such a diagnosis by age, gender and index date with 1:1 ratio. Exposure to potential protective/risk factors will be included in both conventional logistic regression and machine-learning models. Established risk factors of interest will include diabetes mellitus, midlife hypertension, midlife obesity, depression, head injuries and low education. Exploratory risk factors will include vascular disease, infectious disease and medication. The prediction accuracy of several state-of-the-art machine-learning algorithms will be compared.

ETHICS AND DISSEMINATION

This study was approved by Institutional Review Board of The University of Hong Kong/Hospital Authority Hong Kong West Cluster (UW 18-225). Patients' records are anonymised to protect privacy. Study results will be disseminated through peer-reviewed publications. Codes of the resulted dementia risk prediction algorithm will be made publicly available at the website of the Tools to Inform Policy: Chinese Communities' Action in Response to Dementia project (https://www.tip-card.hku.hk/).

Sleep, brain vascular health and ageing

Sleep maintains the function of the entire body through homeostasis. Chronic sleep deprivation (CSD) is a prime health concern in the modern world. Previous reports have shown that CSD has profound negative effects on brain vasculature at both the cellular and molecular levels, and that this is a major cause of cognitive dysfunction and early vascular ageing. However, correlations among sleep deprivation (SD), brain vascular changes and ageing have barely been looked into. This review attempts to correlate the alterations in the levels of major neurotransmitters (acetylcholine, adrenaline, GABA and glutamate) and signalling molecules (Sirt1, PGC1α, FOXO, P66^shc, PARP1) in SD and changes in brain vasculature, cognitive dysfunction and early ageing. It also aims to connect SD-induced loss in the number of dendritic spines and their effects on alterations in synaptic plasticity, cognitive disabilities and early vascular ageing based on data available in scientific literature. To the best of our knowledge, this is the first article providing a pathophysiological basis to link SD to brain vascular ageing.

The role of Apolipoprotein E epsilon4 in the association between psychosocial working conditions and dementia

In this population-based prospective study, we examined the association of job demand-control combinations with dementia, and explored the roles of Apolipoprotein E epsilon4 (APOE ɛ4) and work duration in this association. A total of 2,579 dementia-free individuals aged 60+ years from Sweden were followed over 12 years. Dementia diagnosis was made by physicians. Lifelong occupational experience was collected, and job demands and control were assessed using a psychosocial job-exposure matrix. Data were analyzed using multivariate Cox proportional hazard models. During the follow-up, 282 people developed dementia. Passive jobs (low control/low demands) were related to a higher risk of dementia compared with active jobs (high control/high demands) among the younger-old (aged ≤72 years), but not among the older-old (aged ≥78 years). Among the younger-old, compared to those with no passive job experience, those with 11+ years in passive jobs had a higher dementia risk. The joint-effect analyses showed that APOE ɛ4 carriers with passive jobs had an even higher risk of dementia compared to APOE ɛ4 non-carriers with active jobs. These findings suggest that passive jobs are related to a higher dementia risk among the younger-old. APOE ɛ4 and long work duration may amplify the impact of passive jobs on dementia.

Multitasking in older adults with type 2 diabetes: A cross-sectional analysis

Background and purpose

Deficits in the ability to multitask contribute to gait abnormalities and falls in many at-risk populations. However, it is unclear whether older adults with type 2 diabetes mellitus (DM) also demonstrate impairments in multitasking. The purpose of this study was to compare multitasking performance in cognitively intact older adults with and without DM and explore its relationship to measures of gait and functional ability.

Methods

We performed a cross-sectional analysis of 40 individuals aged 60 and older with type 2 DM and a matched group of 40 cognitively intact older adults without DM. Multitasking was examined via the ambulatory Walking and Remembering Test (WART) and seated Pursuit Rotor Test (PRT). Self-selected normal and fast walking speed and stride length variability were quantitatively measured, and self-reported functional ability was assessed via the Late Life Function and Disability Index (LLFDI).

Results

Participants with DM walked slower and took more steps off path when multitasking during the WART. No between-group differences in multitasking performance were observed on the PRT. Multitasking performance demonstrated little correlation with gait and functional ability in either group.

Discussion and conclusions

Older adults with DM appear to perform poorly on an ambulatory measure of multitasking. However, we analyzed a relatively small, homogenous sample of older adults with and without type 2 DM and factors such as peripheral neuropathy and the use of multiple comparisons complicate interpretation of the data. Future research should explore the interactions between multitasking and safety, fall risk, and function in this vulnerable population. Clinicians should recognize that an array of factors may contribute to gait and physical dysfunction in older adults with type 2 diabetes, and be prepared to assess and intervene appropriately.

Prevention of Alzheimer disease: The roles of nutrition and primary care

Risk factors for developing Alzheimer disease include hypercholesterolemia, hypertension, obesity, and diabetes. Due to lack of effective treatments for Alzheimer disease, nutrition and primary prevention becomes important.

Electroacupuncture Suppressed Neuronal Apoptosis and Improved Cognitive Impairment in the AD Model Rats Possibly via Downregulation of Notch Signaling Pathway

Acupuncture is a potential strategy for the treatment of Alzheimer's disease (AD) and the possible mechanisms worth to be explored. In this study, we proposed and tested the hypothesis that whether Notch signaling pathway is involved in the effect of electroacupuncture (EA) treatment. Rats that received EA treatment on the acupoints of Baihui (Du 20) and Shenshu (BL 23) had shorter latency and remained in the original platform quadrant longer and crossed the former platform contained quadrant more frequently compared to the Aβ injection rats without EA treatment. EA obviously alleviated the cell apoptosis resulted by Aβ infusion in hippocampus CA1 regions through upregulating the expression of Bcl-2 and downregulating the expression of Bax. EA could further obviously promote the expression of synapsin-1 and synaptophysin in hippocampus. Aβ injection significantly increased the expression of Notch1, Jag1, and Hes1 mRNA, while EA treatment downregulated the level of Notch1 and Hes1 mRNA in hippocampus, but not Jag1 mRNA. Our data suggested that EA treatment improved learning and memory function in the AD rat model partially through downregulating Notch signaling pathway.

Caffeine Intake from Coffee or Tea and Cognitive Disorders: A Meta-Analysis of Observational Studies

Background: Observational epidemiological studies such as cross-sectional, case-control, and cohort studies have reported inconsistent findings regarding the association between caffeine intake from coffee or tea and the risk of cognitive disorders such as dementia, Alzheimer's disease, cognitive impairment, and cognitive decline. Methods: We searched PubMed and EMBASE in September 2014. Three evaluators independently extracted and reviewed articles, based on predetermined selection criteria. Results: Out of 293 articles identified through the search and bibliographies of relevant articles, 20 epidemiological studies from 19 articles, which involved 31,479 participants (8,398 in six cross-sectional studies, 4,601 in five case-control studies, and 19,918 in nine cohort studies), were included in the final analysis. The pooled odds ratio (OR) or relative risk (RR) of caffeine intake from coffee or tea for cognitive disorders (dementia, Alzheimer's disease, cognitive impairment, and cognitive decline) was 0.82 (95% confidence interval [CI], 0.67-1.01, I2 = 63.2%) in a random-effects meta-analysis. In the subgroup meta-analysis by caffeine sources, the summary OR or RR of coffee intake was 0.83 (95% CI, 0.70-0.98; I2 = 44.8%). However, in the subgroup meta-analysis by study design, the summary estimates (RR or OR) of coffee intake for cognitive disorders were 0.70 (95% CI, 0.50-0.98; I2 = 42.0%) for cross-sectional studies, 0.82 (95% CI, 0.55-1.24; I2 = 33.4%) for case-control studies, and 0.90 (95% CI, 0.59-1.36; I2 = 60.0%) for cohort studies. Conclusions: This meta-analysis found that caffeine intake from coffee or tea was not associated with the risk of cognitive disorders.

25-Hydroxyvitamin D and cognitive performance in mid-life

Hypovitaminosis D has been linked with poor cognitive function, particularly in older adults, but studies lack a lifespan approach; hence, the effects of reverse causality remain unknown. In the present study, we aimed to assess the relationship between 25-hydroxyvitamin D (25(OH)D) concentrations and subsequent cognitive performance in mid-adulthood and the influence of earlier life factors, including childhood cognitive ability, on this association. Information for the present study was obtained from the members of the 1958 British birth cohort (n 6496). Serum 25(OH)D concentration, indicating vitamin D status, was measured at age 45 years. Verbal memory (immediate and delayed word recall), verbal fluency (animal naming) and speed of processing were tested at age 50 years. Information on childhood cognitive ability, educational attainment, vitamin D-related behaviours and other covariates was collected prospectively from participants throughout their life. Childhood cognitive ability and educational attainment by age 42 years were strongly correlated with cognitive performance at age 50 years and with several vitamin D-related behaviours in mid-adulthood, but not with 25(OH)D concentrations at age 45 years. Participants with both low ( < 25 nmol/l) and high ( ≥ 75 nmol/l) 25(OH)D concentrations at age 45 years performed significantly worse on immediate word recall. The associations attenuated after adjustment for childhood cognitive ability, education, and socio-economic position; however, for the immediate word recall test, there was a non-linear association with 25(OH)D after further adjustment for obesity, menopausal status, smoking, alcohol consumption, physical activity and depressive symptoms at age 45 years (Pcurvature= 0·01). The present study demonstrated that 25(OH)D concentrations were non-linearly associated with immediate word recall in mid-life. A clarification of the level of 25(OH)D concentrations that is most beneficial for predicting better cognitive performance in mid-life is required.

Predicting the risk of dementia among Canadian seniors: a useable practice-friendly diagnostic algorithm

Research has not provided feasible models to identify dementia in primary care. We construct a broadly based diagnostic algorithm synthesizing information from known risk factors, such as poor cognition, sociodemographic factors, and health history. Data were from the Canadian Study of Health and Aging (CSHA) Phase I. Dementia was diagnosed by clinical consensus. All subjects had a Mini-Mental State Examination (MMSE) score and a Modified MMSE (3MS) score. Multiple logistic regression was used to build our diagnostic algorithm, which was then tested for classification accuracy on the basis of the area under the receiver operating characteristic curve. The area under receiver operating characteristic curve for our diagnostic algorithm using 3MS as a binary variable was significantly greater than the 3MS alone (P<0.001). However, no significant difference was found when using 3MS as a continuous variable in the algorithm. Similarly, a binary MMSE algorithm would provide greater accuracy than MMSE alone. In terms of the usage of our algorithm in practice settings, given the prevalence of dementia, the clear benefits of accurate identification and earlier intervention, adding a few questions to the binary 3MS in our algorithm quantitatively improves the dementia prediction, which is important for patients, caregivers, and health providers.