Dementia in China: epidemiology, clinical management, and research advances

Trends in Prevalence and Disability-Adjusted Life-Years of Alzheimer's Disease and Other Dementias in China from 1990 to 2019

INTRODUCTION

China has the largest population of people with dementia in the world and is estimated to have approximately a quarter of the entire population with dementia worldwide, bringing a heavy burden on the public and healthcare systems. We aimed to analyze the burden of Alzheimer's disease and other dementias in China over the past three decades.

METHODS

The data on disease burden owing to Alzheimer's disease and other dementias in China from 1990 to 2019 were extracted from the Global Burden of Disease (GBD) 2019 datasets. The estimated annual percentage changes (EAPCs) were calculated to assess the temporal trends, and the ratio of years lived with disability (YLDs) to disability-adjusted life-years (DALYs) was used as an indicator to evaluate the healthcare system.

RESULT

In China, the overall age-standardized rates (ASRs) of the prevalence and DALYs of Alzheimer's disease and other dementias increased from 1990 to 2019, and their EAPCs were 0.66 (95% confidence interval [CI], 0.57-0.75) and 0.26 (95% CI, 0.21-0.31), respectively. ASRs and the total number of dementia in females remained higher than in males, but the upward trend in ASRs among men was more pronounced than in women. The female-to-male ratio of the age-standardized DALY rate peaked in the 75-79 year age group in 2019 (female-to-male ratio of 1.32). The YLDs:DALYs ratio in China experienced a gradual increase and finally stayed above the global average since 2011.

CONCLUSION

China has experienced a remarkably rising burden of dementia over the past three decades. The more significant burden of dementia was in females, but the potentially increasing burden of dementia in males cannot be underestimated.

White Matter Changes as an Independent Predictor of Alzheimer's Disease

BACKGROUND

Abnormalities in white matter (WM) may be a crucial physiologic feature of Alzheimer's disease (AD). However, neuroimaging's ability to visualize the underlying functional degradation of the WM region in AD is unclear.

OBJECTIVE

This study aimed to explore the differences in amplitude of low-frequency fluctuation (ALFF) and fractional ALFF (fALFF) in the WM region of patients with AD and healthy controls (HC) and to investigate further whether these values can provide supplementary information for diagnosing AD.

METHODS

Forty-eight patients with AD and 46 age-matched HC were enrolled and underwent resting-state functional magnetic resonance imaging and a neuropsychological battery assessment. We analyzed the differences in WM activity between the two groups and further explored the correlation between WM activity in the different regions and cognitive function in the AD group. Finally, a machine learning algorithm was adopted to construct a classifier in detecting the clinical classification ability of the values of ALFF/ALFF in the WM.

RESULTS

Compared with HCs, patients with AD had lower WM activity in the right anterior thalamic radiation, left frontal aslant tract, and left forceps minor, which are all positively related to global cognitive function, memory, and attention function (all p < 0.05). Based on the combined WM ALFF and fALFF characteristics in the different regions, individuals not previously assessed were classified with moderate accuracy (75%), sensitivity (71%), specificity (79%), and area under the receiver operating characteristic curve (85%).

CONCLUSION

Our results suggest that WM activity is reduced in AD and can be used for disease classification.

Prevalence and Progression of Subjective Cognitive Decline Among Rural Chinese Older Adults: A Population-Based Study

BACKGROUND

Few community-based studies have examined occurrence and progression of subjective cognitive decline (SCD).

OBJECTIVE

To investigate prevalence and progression of SCD among rural-dwelling Chinese elderly people.

METHODS

This cohort study included 2,488 cognitively unimpaired adults (age≥65 years) who were examined at baseline (2014-2015) and followed in 2018. Demographic, epidemiological, clinical, and neuropsychological data were collected via in-person interviews and clinical examinations following a structured questionnaire. At baseline, SCD was assessed using the self-rated Ascertain Dementia 8-item Questionnaire. At follow-up, Alzheimer's disease (AD) and vascular dementia (VaD) were clinically diagnosed following the international criteria. Data were analyzed using logistic regression models.

RESULTS

The prevalence of SCD was 40.07%. SCD at baseline was associated with the multivariable-adjusted odds ratio (OR) of 1.51 (95% confidence interval 1.10-2.07) for incident cognitive impairment, no dementia (CIND) and 3.11 (1.64-5.93) for incident AD. Among people with SCD at baseline, the multivariable-adjusted OR of incident CIND was 0.55(0.32-0.96) for hyperlipidemia; the multivariable-adjusted OR of incident AD was 1.21 (1.14-1.30) for older age, 0.32 (0.12-0.88) for high education, 2.60 (1.11-6.08) for carrying APOEɛ4 allele, and 0.34 (0.13-0.86) for high social support, whereas the multivariable-adjusted OR of incident VaD was 6.30 (1.71-23.18) for obesity.

CONCLUSION

SCD affects over 40% of rural-dwelling cognitively unimpaired older adults in China. SCD is associated with accelerated progression to CIND and AD. Older age, lack of school education, APOEɛ4 allele, and low social support are associated with an increased risk of progression from SCD to AD, whereas obesity is related to accelerated progression to VaD.

A global view of the genetic basis of Alzheimer disease

The risk of Alzheimer disease (AD) increases with age, family history and informative genetic variants. Sadly, there is still no cure or means of prevention. As in other complex diseases, uncovering genetic causes of AD could identify underlying pathological mechanisms and lead to potential treatments. Rare, autosomal dominant forms of AD occur in middle age as a result of highly penetrant genetic mutations, but the most common form of AD occurs later in life. Large-scale, genome-wide analyses indicate that 70 or more genes or loci contribute to AD. One of the major factors limiting progress is that most genetic data have been obtained from non-Hispanic white individuals in Europe and North America, preventing the development of personalized approaches to AD in individuals of other ethnicities. Fortunately, emerging genetic data from other regions - including Africa, Asia, India and South America - are now providing information on the disease from a broader range of ethnicities. Here, we summarize the current knowledge on AD genetics in populations across the world. We predominantly focus on replicated genetic discoveries but also include studies in ethnic groups where replication might not be feasible. We attempt to identify gaps that need to be addressed to achieve a complete picture of the genetic and molecular factors that drive AD in individuals across the globe.

The neuroprotective effects of peracetylated chitosan oligosaccharides against β-amyloid-induced cognitive deficits in rats

Chitosan oligosaccharides (COSs) have been reported to possess a broad range of activities such as antitumor, antioxidant and neuroprotective activities. In this study, the protective effects and mechanisms of peracetylated chitosan oligosaccharides (PACOs) against Aβ-induced cognitive deficits were investigated in Sprague-Dawley (SD) rats. PACOs treatment significantly improved the learning and memory function of Alzheimer's disease (AD) rats and attenuated the neuron cell damage caused by Aβ. PACOs also markedly reduced the levels of lactate dehydrogenase (LDH) and Malondialdehyde (MDA) and decreased the phosphorylation of Tau protein to inhibit oxidative injury and inflammatory responses in AD rats. Further studies indicated that PACOs may promote the repair of Aβ induced nerve damage and inhibit neuronal apoptosis mainly through regulating PI3K/Akt/GSK3β signaling pathway. Consistently, the transcriptome analysis verified that the differentially expressed genes (DEGs) were mainly involved in neuron development and the PI3K-Akt signaling pathway. Taken together, peracetylated chitosan oligosaccharides (PACOs) have the potential to be developed into novel anti-AD agents targeting the cellular PI3K/Akt/GSK3β signaling pathway.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42995-023-00172-3.

Three-round learning strategy based on 3D deep convolutional GANs for Alzheimer's disease staging

Accurately diagnosing of Alzheimer's disease (AD) and its early stages is critical for prompt treatment or potential intervention to delay the the disease's progression. Convolutional neural networks (CNNs) models have shown promising results in structural MRI (sMRI)-based diagnosis, but their performance, particularly for 3D models, is constrained by the lack of labeled training samples. To address the overfitting problem brought on by the insufficient training sample size, we propose a three-round learning strategy that combines transfer learning with generative adversarial learning. In the first round, a 3D Deep Convolutional Generative Adversarial Networks (DCGAN) model was trained with all available sMRI data to learn the common feature of sMRI through unsupervised generative adversarial learning. The second round involved transferring and fine-tuning, and the pre-trained discriminator (D) of the DCGAN learned more specific features for the classification task between AD and cognitively normal (CN). In the final round, the weights learned in the AD versus CN classification task were transferred to the MCI diagnosis. By highlighting brain regions with high prediction weights using 3D Grad-CAM, we further enhanced the model's interpretability. The proposed model achieved accuracies of 92.8%, 78.1%, and 76.4% in the classifications of AD versus CN, AD versus MCI, and MCI versus CN, respectively. The experimental results show that our proposed model avoids overfitting brought on by a paucity of sMRI data and enables the early detection of AD.

NAFLD does not increase the risk of incident dementia: A prospective study and meta-analysis

The association between nonalcoholic fatty liver disease (NAFLD) and incident dementia remains unclear. This study aimed to explore whether NAFLD was associated with the risk of incident dementia. We conducted a prospective analysis of 179,222 UK Biobank participants. NAFLD was diagnosed based on the fatty liver index. Cox proportional hazards models were used to estimate the adjusted hazard ratio (HR) and 95% confidence interval (CI) of NAFLD for incident dementia. The results from this and six previous prospective studies were combined in meta-analyses. During a median follow-up of 12.4 years (2,149,839 person-years), 4950 incident dementia cases, including 2318 Alzheimer's disease (AD) cases and 1135 vascular dementia (VD) cases, were identified. There was no significant association between NAFLD and the risks of all-cause dementia (HR: 0.97, 95% CI: 0.90-1.06; P = 0.528). NAFLD was also not significantly associated with AD or VD (HR: 0.95, 95% CI: 0.84-1.07, P = 0.401; HR: 1.03, 95% CI: 0.88-1.22, P = 0.689, respectively). Our meta-analyses of prospective studies included 879,749 subjects. The pooled HR of NAFLD for all-cause dementia was 1.01 (95% CI: 0.94-1.08), and that for VD was 0.99 (95% CI: 0.86-1.13). All included cohort studies were of high quality as assessed by the Newcastle‒Ottawa scale. We found no evidence of an association between NAFLD and incident dementia.

Association between positive control in self-perceptions of aging and motoric cognitive risk syndrome among Chinese community-dwelling older adults: a cross-sectional study

BACKGROUND

Self-perceptions of aging (SPA) are important psychosocial factors that lead to a wide range of outcomes including dementia. However, the relationships between positive SPA and motoric cognitive risk syndrome (MCR) which is a predementia syndrome are still unknown. This study aimed to reveal the associations of positive control and aging awareness of SPA with the risk of MCR and its components.

METHODS

A cross-sectional design was conducted among 1137 Chinese community-dwelling older adults. Positive control and aging awareness were defined by two dimensions of SPA (Positive control and Timeline chronic). MCR was determined according to definition. Multivariable logistic regression was used to examine the associations.

RESULTS

The overall prevalence of MCR was 11.5% (mean age = 71.62 ± 5.22). After adjusting for depression, anxiety, and cognitive function, positive control was associated with reduced risk of MCR (OR = 0.624, 95% CI 0.402-0.969, P = 0.036), subjective cognitive complaints (SCC) (OR = 0.687, 95% CI 0.492-0.959, P = 0.027), and gait speed (GS) (OR = 0.377, 95% CI 0.197-0.720, P = 0.003), respectively. Aging awareness was merely related to increased risk of MCR (OR = 1.386, 95% CI 1.062-1.810, P = 0.016).

CONCLUSIONS

This study highlights the crucial associations of positive control and aging awareness with MCR and its components. Our results emphasize that positive belief in control and adaptive aging awareness might be promising targets for preventing MCR.

Associates of Perceived Quality of Life in Chinese Older Adults Living with Cognitive Impairment

The aim of this study is to examine perceived quality of life in Chinese older adults living with cognitive impairment and explore its associations with caregivers' characteristics. Questionnaires were administered in person to 271 caregiver-care recipient dyads from urban communities in mainland China in 2019. We used the 40-item Alzheimer's Disease-related Quality of Life tool and asked caregiver respondents to indicate care recipients' life conditions. The questionnaire asked caregivers about their sociodemographic characteristics, levels of informal social support, caregiver burden, and depressive symptoms. Caregivers' higher levels of caregiver burden (β = > -0.19, p < .01) and depressive symptoms (β = > -0.19, p < .01) amongst caregivers were significantly associated with lower quality of life among care recipients. Informal support from relatives and friends to caregivers did not significantly affect quality of life of care recipients. The results suggested that reducing caregivers' burden and depressive symptoms are essential to promote quality of life of care recipients. Formal support from health professionals, service organizations, and communities are urgently called to promote the wellbeing of Chinese families affected by cognitive impairment.

Hederagenin improves Alzheimer's disease through PPARα/TFEB-mediated autophagy

BACKGROUND

Autophagic flux is coordinated by a network of master regulatory genes, which centered on transcription factor EB (TFEB). The disorders of autophagic flux are closely associated with Alzheimer's disease (AD), and thus restoring autophagic flux to degrade pathogenic proteins has become a hot therapeutic strategy. Hederagenin (HD), a triterpene compound, isolated from a variety food such as Matoa (Pometia pinnata) Fruit, Medicago sativa, Medicago polymorpha L. Previous studies have shown that HD has the neuroprotective effect. However, the effect of HD on AD and underlying mechanisms are unclear.

PURPOSE

To determine the effect of HD on AD and whether it promotes autophagy to reduce AD symptoms.

STUDY DESIGN

BV2 cells, C. elegans and APP/PS1 transgenic mice were used to explore the alleviative effect of HD on AD and the molecular mechanism in vivo and in vitro.

METHODS

The APP/PS1 transgenic mice at 10 months were randomized into 5 groups (n = 10 in each group) and orally administrated with either vehicle (0.5% CMCNa), WY14643 (10 mg/kg/d), low-dose of HD (25 mg/kg/d), high-dose of HD (50 mg/kg/d) or MK-886 (10 mg/kg/d) + HD (50 mg/kg/d) for consecutive 2 months. The behavioral experiments including morris water maze test, object recognition test and Y maze test were performed. The effects of HD on Aβ deposition and alleviates Aβ pathology in transgenic C. elegans were operated using paralysis assay and fluorescence staining assay. The roles of HD in promoting PPARα/TFEB-dependent autophagy were investigated using the BV2 cells via western blot analysis, real-time quantitative PCR (RT-qPCR), molecular docking, molecular dynamic (MD) simulation, electron microscope assay and immunofluorescence.

RESULTS

In this study, we found that HD upregulated mRNA and protein level of TFEB and increased the distribution of TFEB in the nucleus, and the expressions of its target genes. HD also promoted the expressions of LC3BII/LC3BI, LAMP2, etc., and promoted autophagy and the degradation of Aβ. HD reduced Aβ deposition in the head area of C. elegans and Aβ-induced paralysis. HD improved cognitive impairment and pathological changes in APP/PS1 mice by promoting autophagy and activating TFEB. And our results also showed that HD could strongly target PPARα. More importantly, these effects were reversed by treatment of MK-886, a selective PPARα antagonist.

CONCLUSION

Our present findings demonstrated that HD attenuated the pathology of AD through inducing autophagy and the underlying mechanism associated with PPARα/TFEB pathway.

Investigating the causal association between branched-chain amino acids and Alzheimer's disease: A bidirectional Mendelian randomized study

Background

There are many metabolic pathway abnormalities in Alzheimer's disease (AD). Several studies have linked branched-chain amino acid (BCAA) metabolism disorders with AD but have not obtained consistent results. The purpose of this study is to explore the causal association between BCAA concentration and the risk of AD.

Methods

A bidirectional Mendelian randomized (MR) study was applied to explore the causal effect between BCAA level and the risk of AD. Genetic instrumental variables from the genome-wide association study (GWAS) of serum BCAA levels [total BCAAs (115,047 participants), valine (115,048 participants), leucine (115,074 participants), and isoleucine (115,075 participants)] from the UK Biobank and AD (21,982 AD cases and 41,944 controls) from the International Genomics of Alzheimer's Project were applied to explore the causal effect through the inverse variance-weighted (IVW) method, MR-Egger, and weighted median, accompanied by multiple pluripotency and heterogeneity tests.

Results

The forward MR analysis showed that there was no causal effect of total BCAAs (OR: 1.067, 95% CI: 0.838–1.358; p = 0.838), valine (OR: 1.106, 95% CI: 0.917–1.333; p = 0.292), leucine (OR: 1.096, 95% CI: 0.861–1.396; p = 0.659), and isoleucine (OR: 1.457, 95% CI: 1.024–2.742; p = 0.037) levels on the risk of AD. The reverse analysis showed that AD was related to reduced levels of total BCAAs (OR: 0.979, 95% CI: 0.989–0.990; p &lt; 0.001), valine (OR: 0.977, 95% CI: 0.963–0.991; p = 0.001), leucine (OR: 0.983, 95% CI: 0.973–0.994; p = 0.002), and isoleucine (OR: 0.982, 95% CI: 0.971–0.992; p = 0.001).

Conclusion

We provide robust evidence that AD was associated with a decreased level of BCAAs, which can serve as a marker for early diagnosis of AD.

A Systematic Review of the Association Between Dementia Risk Factors and Cerebrovascular Reactivity

Cumulative evidence suggests that impaired cerebrovascular reactivity (CVR), a regulatory response critical for maintaining neuronal health, is amongst the earliest pathological changes in dementia. However, we know little about how CVR is affected by dementia risk, prior to disease onset. Understanding this relationship would improve our knowledge of disease pathways and help inform preventative interventions. This systematic review investigates 59 studies examining how CVR (measured by magnetic resonance imaging) is affected by modifiable, non-modifiable, and clinical risk factors for dementia. We report that non-modifiable risk (older age and apolipoprotein ε4), some modifiable factors (diabetes, traumatic brain injury, hypertension) and some clinical factors (stroke, carotid artery occlusion, stenosis) were consistently associated with reduced CVR. We also note a lack of conclusive evidence on how other behavioural factors such as physical inactivity, obesity, or depression, affect CVR. This review explores the biological mechanisms underpinning these brain- behaviour associations, highlights evident gaps in the literature, and identifies the risk factors that could be managed to preserve CVR in an effort to prevent dementia.

Metagenomic association analysis of cognitive impairment in community-dwelling older adults

The gut microbiota is reportedly involved in neurodegenerative disorders, and exploration of differences in the gut microbiota in different cognitive status could provide clues for early detection and intervention in cognitive impairment. Here, we used data from the Taizhou Imaging Study (N = 516), a community-based cohort, to compare the overall structure of the gut microbiota at the species level through metagenomic sequencing, and to explore associations with cognition. Interestingly, bacteria capable of producing short-chain fatty acids (SCFAs), such as Bacteroides massiliensis, Bifidobacterium pseudocatenulatum, Fusicatenibacter saccharivorans and Eggerthella lenta, that can biotransform polyphenols, were positively associated with better cognitive performance (p < 0.05). Although Diallister invisus and Streptococcus gordonii were not obviously related to cognition, the former was dominant in individuals with mild cognitive impairment (MCI), while the later was more abundant in cognitively normal (CN) than MCI groups, and positively associated with cognitive performance (p < 0.05). Functional analysis further supported a potential role of SCFAs and lactic acid in the association between the gut microbiota and cognition. The significant associations persisted after accounting for dietary patterns. Collectively, our results demonstrate an association between the gut microbiota and cognition in the general population, indicating a potential role in cognitive impairment. The findings provide clues for microbiome biomarkers of dementia, and insight for the prevention and treatment of dementia.

The viral hypothesis in Alzheimer's disease: SARS-CoV-2 on the cusp

Increasing evidence highlights that infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has long-term effects on cognitive function, which may cause neurodegenerative diseases like Alzheimer's disease (AD) in the future. We performed an analysis of a possible link between SARS-CoV-2 infection and AD risk and proposed several hypotheses for its possible mechanism, including systemic inflammation, neuroinflammation, vascular endothelial injury, direct viral infection, and abnormal amyloid precursor protein metabolism. The purpose of this review is to highlight the impact of infection with SASR-CoV-2 on the future risk of AD, to provide recommendations on medical strategies during the pandemic, and to propose strategies to address the risk of AD induced by SASR-CoV-2. We call for the establishment of a follow-up system for survivors to help researchers better understand the occurrence, natural history, and optimal management of SARS-CoV-2-related AD and prepare for the future.

The role of anxiety and depressive symptoms in mediating the relationship between subjective sleep quality and cognitive function among older adults in China

BACKGROUND

Deterioration of cognitive function has a significant impact on the unavoidable burden on individuals, families, and society. This study aimed to examine the serial multiple mediating effects of anxiety and depressive symptoms on the relationship between subjective sleep quality and cognitive function among older adults in China.

METHODS

We selected 6442 Chinese older adults aged 65 years and older from the 2018 Chinese Longitudinal Healthy Longevity Survey. The SPSS PROCESS macro was employed to perform simple and serial multiple mediation analyses.

RESULTS

Subjective sleep quality, depressive symptoms, anxiety symptoms, and cognitive function were significantly related (P < 0.01). Poor sleep quality can have a direct negative influence on cognitive function among older adults (effect = -0.110; 95 % CI = [-0.166, -0.053]), but it can also have an indirect negative impact via three pathways: the independent mediation of anxiety symptoms (effect = -0.028; 95 % CI = [-0.048, -0.011]), the independent mediation of depressive symptoms (effect = -0.014; 95 % CI = [-0.026, -0.002]), and the serial mediation of anxiety and depressive symptoms (effect = -0.009; 95 % CI = [-0.017, -0.001]).

LIMITATIONS

This study used a cross-sectional design, which restricts the ability to infer causal relationships.

CONCLUSIONS

The effect of subjective sleep quality on cognitive function was serially mediated by anxiety and depressive symptoms among older adults. Diverse therapies targeted at improving sleep quality in older adults may improve mood and cognitive functioning.

Remnant cholesterol and mild cognitive impairment: A cross-sectional study

Objective

Emerging evidence suggests that elevated remnant cholesterol (RC) correlates with several health conditions. To explore the association of plasma RC with MCI incidence and the relationship between plasma RC and different domains of cognition in MCI patients.

Methods

Thirty-six MCI patients and 38 cognitively healthy controls (HC) were enrolled in the present cross-sectional study. Using total cholesterol (TC) minus high-density lipoprotein cholesterol (HDL-C) minus low-density lipoprotein cholesterol (LDL-C) as the formula for calculating fasting RC. Cognition was assessed using the Chinese version of the Montreal cognitive assessment (MoCA), Auditory Verbal Learning Test (AVLT), Digit Symbol Substitution Test (DSST), Trail Making Test (TMT), and Rey-Osterrieth Complex Figure Test (ROCF).

Results

Compared to healthy controls, MCI patients had a higher level of RC, the median difference in RC levels between these two groups was 8.13 mg/dl (95.0%CI: 0.97–16.1). Concurrently, plasma RC level was positively associated with MCI risk (OR = 1.05, 95%CI: 1.01–1.10). Notably, elevated RC level was correlated with impaired cognition in MCI patients, such as DSST (pr = −0.45, p = 0.008), ROCF- Long Delayed Recall (pr = −0.45, p = 0.008), AVLT-Immediate Recall (pr = −0.38, p = 0.028), and TMT-A (pr = 0.44, p = 0.009). Conversely, no significant correlation was found between RC and the AVLT-Long Delayed Recall test.

Conclusion

This study found that plasma remnant cholesterol was associated with MCI. Further large longitudinal studies are needed in the future to confirm the results and clarify the cause-and-effect relationship.

White matter and gray matter changes related to cognition in community populations

Objective

Further studies are needed to improve the understanding of the pathological process underlying cognitive impairments. The purpose of this study is to investigate the global and topographic changes of white matter integrity and cortical structure related to cognitive impairments in a community-based population.

Methods

A cross-sectional analysis was performed based on 995 subjects (aged 56.8 ± 9.1 years, 34.8% males) from the Shunyi study, a community-dwelling cohort. Cognitive status was accessed by a series of neurocognitive tests including Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), category Verbal Fluency Test (VFT), Digit Span Test (DST), and Trail Making Tests A and B (TMT-A and TMT-B). Structural and diffusional MRI data were acquired. White matter integrity was assessed using fractional anisotropy (FA), mean diffusivity (MD), and peak width of skeletonized mean diffusivity (PSMD). Cortical surface area, thickness, and volume were measured using Freesurfer. Probabilistic tractography was further conducted to track the white matter fibers connecting to the cortical regions related to cognition. General linear models were used to investigate the association between brain structure and cognition.

Results

Global mean FA and MD were significantly associated with performances in VFT (FA, β 0.119, p &lt; 0.001; MD, β −0.128, p &lt; 0.001). Global cortical surface area, thickness, and volume were not related to cognitive scores. In tract-based spatial statistics analysis, disruptive white matter integrity was related to cognition impairment, mainly in visuomotor processing speed, semantic memory, and executive function (TMT-A and VFT), rather than verbal short-term memory and working memory (DST). In the whole brain vertex-wise analysis, surface area in the left orbitofrontal cortex, right posterior-dorsal part of the cingulate gyrus, and left central sulcus were positively associated with MMSE and MoCA scores, and the association were independent of the connecting white matter tract.

Conclusion

Disrupted white matter integrity and regional cortical surface area were related to cognition in community-dwelling populations. The associations of cortical surface area and cognition were independent of the connecting white matter tract.

Progress in blood biomarkers of subjective cognitive decline in preclinical Alzheimer's disease

ABSTRACT

Alzheimer's disease (AD) is a neurodegenerative disease that gradually impairs cognitive functions. Recently, there has been a conceptual shift toward AD to view the disease as a continuum. Since AD is currently incurable, effective intervention to delay or prevent pathological cognitive decline may best target the early stages of symptomatic disease, such as subjective cognitive decline (SCD), in which cognitive function remains relatively intact. Diagnostic methods for identifying AD, such as cerebrospinal fluid biomarkers and positron emission tomography, are invasive and expensive. Therefore, it is imperative to develop blood biomarkers that are sensitive, less invasive, easier to access, and more cost effective for AD diagnosis. This review aimed to summarize the current data on whether individuals with SCD differ reliably and effectively in subjective and objective performances compared to cognitively normal elderly individuals, and to find one or more convenient and accessible blood biomarkers so that researchers can identify SCD patients with preclinical AD in the population as soon as possible. Owing to the heterogeneity and complicated pathogenesis of AD, it is difficult to make reliable diagnoses using only a single blood marker. This review provides an overview of the progress achieved to date with the use of SCD blood biomarkers in patients with preclinical AD, highlighting the key areas of application and current challenges.

Attitudes toward dementia screening and influential factors in older adults in China

BACKGROUND

Dementia will likely be an ongoing concern for future generations, and according to the World Health Organization, two-thirds of dementia cases are missed diagnoses. We aimed to explore the attitudes of older adults toward dementia screening and the related influencing factors.

METHODS

A multicentre cross-sectional study was conducted. Data were collected using questionnaires between 2020 December and 2021 June from five provinces in China. The study included older adults aged 60 years or older, living in China. A sociodemographic questionnaire and the Perceptions Regarding Investigational Screening for Memory in Primary Care scale were used to assess attitudes toward and influencing factors of dementia screening.

RESULTS

A total of 279 participants completed the questionnaires. The results revealed housing status as a positive factor in the acceptance dimension, while high income was the primary positive factor in the benefits of screening dimension. Having religious beliefs, low income, and never participating in social activities were positive factors for the stigma dimension. Widowed marital status and participation in social activities were negative factors for the independence dimension, while having religious beliefs positively influenced the suffering dimension.

CONCLUSIONS

This study showed that participants held a relatively positive attitude toward dementia screening, although they had concerns about stigma and negative impact on independence. Further studies are required to develop intervention strategies to help older adults improve their attitudes and quality of life, promote cognitive health, and facilitate healthy ageing.

Longitudinal body weight dynamics in relation to cognitive decline over two decades: A prospective cohort study

OBJECTIVE

The aim of this study was to investigate the associations of body weight change (BWC) and body weight variability (BWV) with changes in cognitive function.

METHODS

In 10,340 Health and Retirement Study participants (mean age: 68.0 years), body weight was reported biennially from 1993/1994 to 2016, and cognitive function was measured biennially from 1998 to 2016. We calculated BWC and BWV as the slope and root-mean-square error by regressing body weight on time for each individual. BWC was categorized by quintiles (Q): stable weight (Q2 to Q4), weight loss (Q1), and weight gain (Q5). BWV was categorized by tertiles. We used linear mixed regression models to assess associations with cognitive change.

RESULTS

Compared with stable weight (median: 0 kg/y), weight loss (median: -1.3 kg/y) predicted faster cognitive decline as demonstrated by mean difference of -0.023 (95% CI: -0.027 to -0.019) in cognitive change z score per year, whereas weight gain (median: 1 kg/y) was related to slower cognitive decline (β = 0.006; 95% CI: 0.003 to 0.009). Larger BWV was also associated with faster cognitive decline (β comparing the top with bottom tertile = -0.003; 95% CI: -0.006 to -0.0002). Similar associations were observed for episodic and working memory.

CONCLUSIONS

Weight loss and large BWV over a long time independently predicted faster cognitive decline in middle-aged and older adults, underscoring the importance of long-term dynamic body weight monitoring.

Comorbidity among inpatients with dementia: a preliminary cross-sectional study in West China

OBJECTIVE

To investigate comorbidities among hospitalized patients with dementia.

METHOD

Data were extracted from the discharge records in our hospital. Comorbidities based on ICD-10 were selected from the Charlson Comorbidity Index (CCI) and Elixhauser Comorbidity Index (ECI). The distributions of these comorbidities were described in dementia inpatients and age- and sex-matched nondementia controls, as well as in inpatients with Alzheimer's disease and vascular dementia. A logistic regression model was applied to identify dementia-specific morbid conditions.

RESULTS

A total of 3355 patients with dementia were included, with a majority of 1503 (44.8%) having Alzheimer's disease, 395 (11.8%) with vascular dementia, and 441 (13.1%) with mixed dementia. The mean number of comorbidities was 3.8 in dementia patients (vs. 2.9 in controls). The most prevalent comorbidities in inpatients with dementia compared with those without dementia were cerebral vascular disease (73.0% vs. 35.9%), hypertension (62.8% vs. 56.2%), and peripheral vascular disease (53.7% vs. 31.2%). Comorbidities associated with dementia included epilepsy (OR 4.8, 95% CI 3.5-6.8), cerebral vascular disease (OR 4.1, 95% CI 3.7-4.5), depression (OR 4.0, 95% CI 3.2-5.0), uncomplicated diabetes (OR 1.5, 95% CI 1.4-1.7), peripheral vascular disease (OR 1.8, 95% CI 1.6-2.0), rheumatoid arthritis collagen vascular disease (OR 1.7, 95% CI 1.3-2.3), and anemia (OR 1.2, 95% CI 1.04-1.3). Some comorbidities suggested a protective effect against dementia. They were hypertension (OR 0.8, 95% CI 0.7-0.9), COPD (OR 0.6, 95% CI 0.5-0.6), and solid tumor without metastasis (OR 0.4, 95% CI 0.3-0.4). Vascular dementia has more cardiovascular and cerebrovascular comorbidities than Alzheimer's disease.

CONCLUSION

Patients with dementia coexisted with more comorbidities than those without dementia. Comorbidities (esp. cardio-cerebral vascular risks) in patients with vascular dementia were more than those in patients with AD. Specifically, vascular and circulatory diseases, epilepsy, diabetes and depression increased the risk of dementia.

Shared and unique effects of ApoEε4 and pathogenic gene mutation on cognition and imaging in preclinical familial Alzheimer's disease

BACKGROUND

Neuropsychology and imaging changes have been reported in the preclinical stage of familial Alzheimer's disease (FAD). This study investigated the effects of APOEε4 and known pathogenic gene mutation on different cognitive domains and circuit imaging markers in preclinical FAD.

METHODS

One hundred thirty-nine asymptomatic subjects in FAD families, including 26 APOEε4 carriers, 17 APP and 20 PS1 mutation carriers, and 76 control subjects, went through a series of neuropsychological tests and MRI scanning. Test scores and imaging measures including volumes, diffusion indices, and functional connectivity (FC) of frontostriatal and hippocampus to posterior cingulate cortex pathways were compared between groups and analyzed for correlation.

RESULTS

Compared with controls, the APOEε4 group showed increased hippocampal volume and decreased FC of fronto-caudate pathway. The APP group showed increased recall scores in auditory verbal learning test, decreased fiber number, and increased radial diffusivity and FC of frontostriatal pathway. All three genetic groups showed decreased fractional anisotropy of hippocampus to posterior cingulate cortex pathway. These neuropsychological and imaging measures were able to discriminate genetic groups from controls, with areas under the curve from 0.733 to 0.837. Circuit imaging measures are differentially associated with scores in various cognitive scales in control and genetic groups.

CONCLUSIONS

There are neuropsychological and imaging changes in the preclinical stage of FAD, some of which are shared by APOEε4 and known pathogenic gene mutation, while some are unique to different genetic groups. These findings are helpful for the early identification of Alzheimer's disease and for developing generalized and individualized prevention and intervention strategies.

Identification of TAC1 Associated with Alzheimer's Disease Using a Robust Rank Aggregation Approach

BACKGROUND

Alzheimer's disease (AD) brings heavy burden to society and family. There is an urgent need to find effective methods for disease diagnosis and treatment. The robust rank aggregation (RRA) approach that could aggregate the resulting gene lists has been widely utilized in genomic data analysis.

OBJECTIVE

To identify hub genes using RRA approach in AD.

METHODS

Seven microarray datasets in frontal cortex from GEO database were used to identify differential expressed genes (DEGs) in AD patients using RRA approach. STRING was performed to explore the protein-to-protein interaction (PPI). Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses were utilized for enrichment analysis. Human Gene Connectome and Gene Set Enrichment Analysis were used for functional annotation. Finally, the expression levels of hub genes were validated in the cortex of 5xFAD mice by quantitative real-time polymerase chain reaction.

RESULTS

After RRA analysis, 473 DEGs (216 upregulated and 257 downregulated) were identified in AD samples. PPI showed that DEGs had a total of 416 nodes and 2750 edges. These genes were divided into 17 clusters, each of which contains at least three genes. After functional annotation and enrichment analysis, TAC1 is identified as the hub gene and may be related to synaptic function and inflammation. In addition, Tac1 was found downregulated in cortices of 5xFAD mice.

CONCLUSION

In the current study, TAC1 is identified as a key gene in the frontal cortex of AD, providing insight into the possible pathogenesis and potential therapeutic targets for this disease.

Associations of Lung Function Decline with Risks of Cognitive Impairment and Dementia: A Meta-Analysis and Systematic Review

BACKGROUND

There are controversies surrounding the effects of lung function decline on cognitive impairment and dementia.

OBJECTIVE

We conducted a meta-analysis and systematic review to explore the associations of lung function decline with the risks of cognitive impairment and dementia.

METHODS

The PubMed, EMBASE, and the Cochrane Library were searched to identify prospective studies published from database inception through January 10, 2023. We pooled relative risk (RR) and 95% confidence intervals (CI) using random-effects models. The Egger test, funnel plots, meta-regression, sensitivity, and subgroup analyses were conducted to detect publication bias and investigate the source of heterogeneity.

RESULTS

Thirty-three articles with a total of 8,816,992 participants were subjected to meta-analysis. Poorer pulmonary function was associated with an increased risk of dementia (FEV: RR = 1.25 [95% CI, 1.17-1.33]; FVC: RR = 1.40 [95% CI, 1.16-1.69]; PEF: RR = 1.84 [95% CI, 1.37-2.46]). The results of the subgroup analyses were similar to the primary results. Individuals with lung diseases had a higher combined risk of dementia and cognitive impairment (RR = 1.39 [95% CI, 1.20-1.61]). Lung disease conferred an elevated risk of cognitive impairment (RR = 1.37 [95% CI, 1.14-1.65]). The relationship between lung disease and an increased risk of dementia was only shown in total study participants (RR = 1.32 [95% CI, 1.11-1.57]), but not in the participants with Alzheimer's disease (RR = 1.39 [95% CI, 1.00-1.93]) or vascular dementia (RR = 2.11 [95% CI, 0.57-7.83]).

CONCLUSION

Lung function decline was significantly associated with higher risks of cognitive impairment and dementia. These findings might provide implications for the prevention of cognitive disorders and the promotion of brain health.

Design, synthesis, and biological evaluation of novel N-Benzyl piperidine derivatives as potent HDAC/AChE inhibitors for Alzheimer's disease

The multitarget-directed ligands approach represents a potential strategy to provide effective treatments for Alzheimer's disease (AD) given its multifactorial pathology. Herein, a series of N-benzyl piperidine derivatives were designed, synthesized, and biologically characterized for dual inhibitions of histone deacetylase (HDAC) and acetylcholinesterase (AChE). Among the compounds tested, d5 and d10 exhibited dual enzyme inhibitions (d5: HDAC_IC50 = 0.17 μM, AChE_IC50 = 6.89 μM, d10: HDAC_IC50 = 0.45 μM, AChE_IC50 = 3.22 μM), and both compounds showed activities on scavenging free radical, metal chelating, and inhibiting Aβ aggregations. More importantly, both compounds exhibited promising neuroprotective activities in PC-12 cells and good AChE selectivity. Collectively, the multifunctional profiles of compound d5 and d10 encourage further optimization and exploration to develop more potent analogues as potential treatments for AD.

Absence of fluctuation and inverted circadian rhythm of blood pressure increase the risk of cognitive dysfunction in cerebral small vessel disease patients

BACKGROUND AND PURPOSE

Cerebral small vessel disease (CSVD) is a common cause of stroke and senile vascular cognitive impairment, imposing a heavy burden on public health care systems worldwide. Hypertension and 24-hour blood pressure variability (BPV), known to be significant risk factors for cognitive dysfunction, have been found to be associated with cognitive function in CSVD patients in previous studies. However, as a derived part of BPV, there are few studies on the relationship between circadian rhythm of blood pressure and cognitive dysfunction in CSVD patients, and the relationship between them is still unclear. Thus, this study aimed to investigate whether the disturbance of circadian rhythm of blood pressure can affect the cognitive function of patients with CSVD.

METHODS

A total of 383 CSVD patients hospitalized in the Geriatrics Department of the Lianyungang Second People's Hospital between May 2018 and June 2022 were enrolled in this study. The clinical information and parameters of 24-hour ambulatory blood pressure monitoring were compared between the cognitive dysfunction group (n = 224) and the normal group (n = 159). Finally, a binary logistic regression model was used to assess the relationship between circadian rhythm of blood pressure and cognitive dysfunction in patients with CSVD.

RESULTS

(1) Patients in the cognitive dysfunction group were older, had lower blood pressure on admission, and had a greater number of previous cardiovascular and cerebrovascular diseases (P < 0.05). (2) More patients in the cognitive dysfunction group had circadian rhythm abnormalities in blood pressure, especially the non-dipper and reverse-dipper types (P < 0.001). (3) In the elderly, there was a statistical difference in the circadian rhythm of blood pressure between the cognitive dysfunction group and the normal group, but this phenomenon did not exist in the middle-aged. (4) Binary logistic regression analysis showed that after adjusting for confounding factors, the risk of cognitive dysfunction in CSVD patients with non-dipper type was 4.052 times higher than that of dipper type (95% CI, 1.782-9.211; P = 0.001), and reverse-dipper type was 8.002 times higher than those with dipper type (95% CI, 3.367-19.017; P<0.001).

CONCLUSIONS

The disturbance of circadian rhythm of blood pressure may affect the cognitive function of patients with CSVD, and the risk of cognitive dysfunction in non-dipper and reverse-dipper types are higher.

Self-perceived memory is negatively associated with chronic disease awareness: Evidence from blood biomarker data

Background and objectives

Cognitive misperception contributed to poor decision-making; yet their impact on health-related decisions is less known. We examined how self-perceived memory was associated with chronic disease awareness among older Chinese adults.

Research design and methods

Data were obtained from the China Health and Retirement Longitudinal Study. Nationally representative blood biomarkers were collected in 2015 to identify participants' dyslipidemia and diabetes status. Among participants with biomarker identified dyslipidemia or diabetes, disease awareness was defined as self-reported diagnosis of the conditions as of 2018. The association of self-perceived memory with chronic disease awareness was determined by weighted multivariate logistic regressions adjusting for cognitive ability and covariates.

Results

Among 4578 adults aged 60 and over, 1442 and 759 individuals were identified having dyslipidemia and diabetes, with proportions of disease awareness being 38.0% and 58.1%, respectively. The proportions were lower for individuals with better self-perceived memory and those with more impaired cognitive ability, showing opposite patterns. Adjusting for cognitive ability and covariates, self-perceived memory was negatively associated with the dyslipidemia (OR = 0.80, 95%CI: 0.63-1.02) and diabetes (OR = 0.71, 95%CI: 0.55-0.92) awareness. In particular, older adults with the highest level of self-perceived memory had significantly lower disease awareness as compared to those with the lowest level of self-perceived memory (OR = 0.51, 95%CI: 0.28-0.94 for dyslipidemia; and OR = 0.42, 95%CI: 0.21-0.84 for diabetes). The negative association was robust to adjusting for alternative cognitive measures, and was stronger for individuals with rural status, lower education, or living without children.

Discussion and implications

Cognitive misperception poses great challenges to chronic disease awareness. Targeted interventions and supports are needed, particularly for those more disadvantaged.

Donepezil accelerates the release of PLGA microparticles via catalyzing the polymer degradation regardless of the end groups and molecular weights

Poly (lactic-co-glycolic acid) (PLGA) is one of the most successful polymers for sustained parenteral drug products in the market. However, rational selection of PLGA in the formulations is still challenging due to the lack of fundamental studies. The present study aimed to investigate the influence of donepezil (DP) on the in-vitro and in-vivo performance of PLGA sustained microspheres. Three kinds of PLGAs with different end groups and molecular weights were selected. Then DP-loaded PLGA microspheres (DP-MSs) with similar particle size, drug loading, and encapsulation efficiency were prepared using an o/w emulsion-solvent evaporation method. Laser diffraction and scanning electron microscopy showed that the prepared DP-MSs were about 35 μm and spherical in shape. Differential scanning calorimetry and X-ray diffraction indicated that DP was in an amorphous state inside the microspheres. Unexpectedly, the molecular weight and end group of PLGAs did not significantly influence the in-vitro and in-vivo performance of the DP-MSs. The gel permeation chromatography indicated that the degradation rates of PLGAs were accelerated with the incorporation of DP into the microspheres, and the molecular weight of all three kinds of PLGAs sharply dropped to about 11,000 Da within the initial three days. The basic catalysis effect induced by DP might be responsible for the accelerated degradation of PLGAs, which led to similar in-vitro release profiles of DP from different PLGA matrices. A point-to-point level A correlation between the in-vitro release and the in-vivo absorption was observed, which confirmed the accelerated release of DP from the DP-MSs in-vivo. The results indicated that the influence of DP on the degradation of PLGA should be considered when developing DP-sustained microspheres.

A Group of Long Non-coding RNAs in Blood Acts as a Specific Biomarker of Alzheimer's Disease

Long non-coding RNAs (lncRNAs) have been identified to be involved in the pathogenesis of Alzheimer's disease (AD). In this study, we evaluated whether lncRNAs can be used to discriminate AD patients from controls and patients with other dementias, such as vascular, Parkinson's disease, behavioral variant frontotemporal, and dementia with Lewy body. In this study, we used three datasets to measure the blood lncRNA levels. A pilot study (dataset 1, n = 40; controls, 20; AD, 20) was used to screen for differentially expressed lncRNAs. Dataset 2 (n = 174; controls, 86; AD, 88) was used to identify a lncRNA panel for the diagnostic model. Dataset 3 (n = 333; control, 60; AD, 54; vascular dementia, 53; Parkinson's disease dementia, 55; behavioral variant frontotemporal dementia, 56; and dementia with Lewy body, 55) was used to validate the diagnostic model. In dataset 1, 12 upregulated and 15 downregulated lncRNAs were identified. In dataset 2, a panel of seven lncRNAs was found to have the ability to differentiate AD patients from controls. Finally, this panel was applied to dataset 3 to successfully distinguish AD from other dementias. This study proposes a panel of seven lncRNAs as specific and promising biomarker for AD diagnosis.

Incidence, Clinical Correlates, and Prognostic Impact of Dementia in Heart Failure: A Population-Based Cohort Study

Background

Heart failure (HF) may increase the risk of dementia via shared risk factors.

Objectives

The authors investigated the incidence, types, clinical correlates, and prognostic impact of dementia in a population-based cohort of patients with index HF.

Methods

The previously territory-wide database was interrogated to identify eligible patients with HF (N = 202,121) from 1995 to 2018. Clinical correlates of incident dementia and their associations with all-cause mortality were assessed using multivariable Cox/competing risk regression models where appropriate.

Results

Among a total cohort aged ≥18 years with HF (mean age 75.3 ± 13.0 years, 51.3% women, median follow-up 4.1 [IQR: 1.2-10.2] years), new-onset dementia occurred in 22,145 (11.0%), with age-standardized incidence rate of 1,297 (95% CI: 1,276-1,318) per 10,000 in women and 744 (723-765) per 10,000 in men. Types of dementia were Alzheimer's disease (26.8%), vascular dementia (18.1%), and unspecified dementia (55.1%). Independent predictors of dementia included: older age (≥75 years, subdistribution hazard ratio [SHR]: 2.22), female sex (SHR: 1.31), Parkinson's disease (SHR: 1.28), peripheral vascular disease (SHR: 1.46), stroke (SHR: 1.24), anemia (SHR: 1.11), and hypertension (SHR: 1.21). The population attributable risk was highest for age ≥75 years (17.4%) and female sex (10.2%). New-onset dementia was independently associated with increased risk of all-cause mortality (adjusted SHR: 4.51; P < 0.001).

Conclusions

New-onset dementia affected more than 1 in 10 patients with index HF over the follow-up, and portended a worse prognosis in these patients. Older women were at highest risk and should be targeted for screening and preventive strategies.

Leisure Participation and Cognitive Impairment Among Healthy Older Adults in China

Leisure participation is beneficial to various health outcomes. This study examined a comprehensive list of leisure activities in relation to incidence of cognitive impairment among healthy older adults (65+) in China. Using data from the 2002 to 2018 Chinese Longitudinal Healthy Longevity Survey, we found that most of the leisure activities were protective of cognitive decline and three leisure activities (watching TV, doing housework, and playing cards/mah-jong) stood out as the most important ones. Additionally, our results revealed subgroup variations in the association between leisure participation and cognitive function: Leisure activities such as reading newspapers/books (not significant for the illiterate), gardening (not significant for the illiterate), and regular exercise (not significant for the rural residents) had different effects across different demographic social groups. Our findings suggest that intervention programs designed to prevent cognitive decline for older adults should consider subgroup and cultural variations in order to yield the best outcomes.

A New Smart 2-Min Mobile Alerting Method for Mild Cognitive Impairment Due to Alzheimer's Disease in the Community

The early identification of mild cognitive impairment (MCI) due to Alzheimer's disease (AD), in an early stage of AD can expand the AD warning window. We propose a new capability index evaluating the spatial execution process (SEP), which can dynamically evaluate the execution process in the space navigation task. The hypothesis is proposed that there are neurobehavioral differences between normal cognitive (NC) elderly and AD patients with MCI reflected in digital biomarkers captured during SEP. According to this, we designed a new smart 2-min mobile alerting method for MCI due to AD, for community screening. Two digital biomarkers, total mission execution distance (METRtotal) and execution distance above the transverse obstacle (EDabove), were selected by step-up regression analysis. For the participants with more than 9 years of education, the alerting efficiency of the combination of the two digital biomarkers for MCI due to AD could reach 0.83. This method has the advantages of fast speed, high alerting efficiency, low cost and high intelligence and thus has a high application value for community screening in developing countries. It also provides a new intelligent alerting approach based on the human-computer interaction (HCI) paradigm for MCI due to AD in community screening.

Brain Activation During Working Memory Task in Amnestic Mild Cognitive Impairment Patients and Its Association with Memory and Attention

BACKGROUND

Amnestic mild cognitive impairment (aMCI) is regarded as a transitional state of Alzheimer's disease, with working memory (WM) impairment.

OBJECTIVE

To investigate the brain activity in aMCI patients during WM tasks with the functional near-infrared spectroscopy (fNIRS) technique, as well as explore the association between brain activity and cognitive function in multiple domains.

METHODS

This study is a case-control study of 54 aMCI patients and 33 cognitively healthy elderly (NC). All participants underwent neuropsychological assessments. fNIRS was applied to examine the brain activation during the WM task. Multivariable linear regression analysis was applied to evaluate associations between brain activation and cognitive function in multiple domains.

RESULTS

Compared to NC subjects, aMCI patients had lower activation in the bilateral prefrontal, parietal, and occipital cortex during the WM task. Additionally, activation in the left prefrontal, bilateral parietal, and occipital cortex during the encoding and maintenance phase was positively associated with memory function. During memory retrieval, higher activity in the left prefrontal, parietal, and occipital cortex were correlated with higher memory scores. Besides, a positive association also formed between attention function and the activation in the left prefrontal, parietal, and occipital cortex during the WM task.

CONCLUSION

These findings demonstrated that reduced activation in the prefrontal, parietal and occipital cortex during WM might reflect the risk of cognitive impairment, especially memory and attention function in aMCI patients. Given the brain activation visualization, fNIRS may be a convenient and alternative tool for screening the risk of Alzheimer's disease.

Plasma Core Alzheimer's Disease Biomarkers Predict Amyloid Deposition Burden by Positron Emission Tomography in Chinese Individuals with Cognitive Decline

Blood-based biomarkers have been considered as a promising method for the diagnosis of Alzheimer's disease (AD). The reliability and accuracy of plasma core AD biomarkers, including phosphorylated tau (P-tau181), total tau (T-tau), Aβ42, and Aβ40, have also been confirmed in diagnosing AD and predicting cerebral β-amyloid (Aβ) deposition in Western populations, while fewer research studies have ever been conducted in China's Han population. In this study, we investigated the capability of plasma core AD biomarkers in predicting cerebral Aβ deposition burden among the China Aging and Neurodegenerative Disorder Initiative (CANDI) cohort consisting of cognitively normal (CN), mild cognitive impairment (MCI), AD dementia, and non-Alzheimer's dementia disease (Non-ADD). Body fluid (plasma and CSF) AD core biomarkers were measured via single-molecule array (Simoa) immunoassay. The global standard uptake value ratio (SUVR) was then calculated by ¹⁸F-florbetapir PET, which was divided into positive (+) and negative (-). The most significant correlation between plasma and CSF was plasma P-tau181 (r = 0.526, P < 0.0001). Plasma P-tau181 and P-tau181/T-tau ratio were positively correlated with global SUVR (r = 0.257, P < 0.0001; r = 0.263, P < 0.0001, respectively), while Aβ42 and Aβ42/Aβ40 ratio were negatively correlated with global SUVR (r = -0.346, P < 0.0001; r = -0.407, P < 0.0001, respectively). Interestingly, voxel-wise analysis showed that plasma P-tau181 and P-tau181/T-tau ratio were negatively related to ¹⁸F-florbetapir PET in the hippocampus and parahippocampal cortex. The optimal predictive capability in distinguishing all Aβ+ participants from Aβ- participants and MCI+ from MCI- subgroups was the plasma P-tau181/T-tau ratio (AUC = 0.825 and 0.834, respectively). Our study suggested that plasma P-tau181 and P-tau181/T-tau ratio possessed better diagnostic and predictive values than plasma Aβ42 and Aβ42/Aβ40 in this cohort, a finding that may be useful in clinical practices and trials in China.

Female perspective: the burden of Alzheimer's disease and other dementias in China from 1990 to 2019 and prediction of their prevalence up to 2044

Background

Dementia is more prevalent in women than in men across the world, and sex differences are reflected in the burden of dementia borne by women and men. However, a few studies have specifically analyzed the disease burden of dementia in Chinese women.

Objective

This article aims to raise awareness of Chinese females with dementia (CFWD), outline an effective response to future trends in China from a female perspective, and provide a reference for the scientific formulation of dementia prevention and treatment policies in China.

Methods

In this article, epidemiological data on dementia in Chinese women were obtained from the Global Burden of Disease Study 2019, and three risk factors, namely, smoking, a high body mass index, and a high fasting plasma glucose, were selected for the analysis. This article also predicted the burden of dementia in Chinese women in the next 25 years.

Results

The prevalence of dementia, mortality, and disability-adjusted life year rates increased with age in CFWD in 2019. All three risk factors provided by the Global Burden of Disease Study 2019 showed positive correlations for the effect of disability-adjusted life years (DALYs) rates on CFWD. Among them, a high body mass index had the greatest effect (8%) and smoking had the smallest effect (6.4%). Over the next 25 years, the number of CFWD and its prevalence are expected to be on the rise, while mortality is expected to remain relatively stable and decline slightly, but deaths from dementia will continue to increase.

Conclusions

The situation arising due to the spread of dementia among Chinese women in the future is going to become a serious issue. To reduce the burden of dementia, the Chinese government should prioritize its prevention and treatment. A multi-dimensional, long-term care system involving families, community, and hospitals should also be established and supported.

A new early warning method for mild cognitive impairment due to Alzheimer's disease based on dynamic evaluation of the "spatial executive process"

Objective

Mild cognitive impairment (MCI) due to Alzheimer's disease (AD), as an early stage of AD, is an important point for early warning of AD. Neuropathological studies have shown that AD pathology in pre-dementia patients involves the hippocampus and caudate nucleus, which are responsible for controlling cognitive mechanisms such as the spatial executive process (SEP). The aim of this study is to design a new method for early warning of MCI due to AD by dynamically evaluating SEP.

Methods

We designed fingertip interaction handwriting digital evaluation paradigms and analyzed the dynamic trajectory of fingertip interaction and image data during "clock drawing" and "repetitive writing" tasks. Extracted fingertip interaction digital biomarkers were used to assess participants' SEP disorders, ultimately enabling intelligent diagnosis of MCI due to AD. A cross-sectional study demonstrated the predictive performance of this new method.

Results

We enrolled 30 normal cognitive (NC) elderly and 30 MCI due to AD patients, and clinical research results showed that there may be neurobehavioral differences between the two groups in digital biomarkers captured during SEP. The early warning performance for MCI due to AD of this new method (areas under the curve (AUC) = 0.880) is better than that of the Minimum Mental State Examination (MMSE) neuropsychological scale (AUC = 0.856) assessed by physicians.

Conclusion

Patients with MCI due to AD may have SEP disorders, and this new method based on dynamic evaluation of SEP will provide a novel human-computer interaction and intelligent early warning method for home and community screening of MCI due to AD.

Alterations in Peripheral Metabolites as Key Actors in Alzheimer's Disease

Growing evidence supports that Alzheimer's disease (AD) could be regarded as a metabolic disease, accompanying central and peripheral metabolic disturbance. Nowadays, exploring novel and potentially alternative hallmarks for AD is needed. Peripheral metabolites based on blood and gut may provide new biochemical insights about disease mechanisms. These metabolites can influence brain energy homeostasis, maintain gut mucosal integrity, and regulate the host immune system, which may further play a key role in modulating the cognitive function and behavior of AD. Recently, metabolomics has been used to identify key AD-related metabolic changes and define metabolic changes during AD disease trajectory. This review aims to summarize the key blood- and microbial-derived metabolites that are altered in AD and identify the potential metabolic biomarkers of AD, which will provide future targets for precision therapeutic modulation.

Correlation between serum lipid profiles and cognitive impairment in old age: a cross-sectional study

Background

The correlation between cognitive function and lipid profiles, including total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides, is inconsistent.

Aims

This cross-sectional study investigated the association between serum lipid levels and the prevalence of cognitive impairment among community-dwelling older adults and explored this difference in association by gender and urban-rural residency.

Methods

Participants aged 65 and above in urban and rural areas were recruited between 2018 and 2020, selected from the Hubei Memory and Aging Cohort Study. Detailed neuropsychological evaluations, clinical examinations and laboratory tests were conducted in community health service centres. Multivariate logistic regression was used to analyse the correlation between serum lipid profiles and the prevalence of cognitive impairment.

Results

We identified 1 336 cognitively impaired adults (≥65 years)-1 066 with mild cognitive impairment and 270 with dementia-from 4 746 participants. Triglycerides level was correlated with cognitive impairment in the total sample (χ²=6.420, p=0.011). In gender-stratified multivariate analysis, high triglycerides in males reduced the risk of cognitive impairment (OR: 0.785, 95% CI: 0.623 to 0.989, p=0.040), and high LDL-C in females increased the risk of cognitive impairment (OR: 1.282, 95% CI: 1.040 to 1.581, p=0.020). In both gender-stratified and urban-rural stratified multivariate analyses, high triglycerides reduced the risk of cognitive impairment in older urban men (OR: 0.734, 95% CI: 0.551 to 0.977, p=0.034), and high LDL-C increased the risk of cognitive impairment in older rural women (OR: 1.830, 95% CI: 1.119 to 2.991, p=0.016).

Conclusions

There are gender and urban-rural differences in the correlation of serum lipids with cognitive impairment. High triglycerides levels may be a protective factor for cognitive function in older urban men, while high LDL-C levels may be a risk factor for cognitive function in older rural women.

Brain Gray Matter Volume Mediated the Correlation Between Plasma P-Tau and Cognitive Function of Early Alzheimer's Disease in China: A Cross-Sectional Observational Study

BACKGROUND

The primary manifestations of Alzheimer's disease (AD) include cognitive decline and brain gray matter volume (GMV) atrophy. Recent studies have found that plasma phosphorylated-tau (p-tau) concentrations perform better in diagnosing, differentiating, and monitoring the progression of AD. However, the correlation between plasma p-tau, GMV, and cognition remains unclear.

OBJECTIVE

To investigate whether GMV plays a mediating role in the association between plasma p-tau concentrations and cognition.

METHODS

In total, 99 participants (47 patients with AD and 52 cognitively unimpaired [CU] individuals) were included. All participants underwent neuropsychological assessments, laboratory examinations, and magnetic resonance imaging scans. Plasma p-tau217 and p-tau181 concentrations were measured using an enzyme-linked immunosorbent assay kit. Voxel-based morphometry was performed to assess participants' brain GMV. Partial correlation and mediation analyses were conducted in AD group.

RESULTS

Plasma p-tau concentrations were significantly higher in the AD group than in the CU group. Patients with AD had significant brain GMV atrophy in the right hippocampus, bilateral middle temporal gyrus, and right inferior temporal gyrus. In the AD group, there were significant correlations between plasma p-tau217 concentrations, GMV, and Mini-Mental State Examination (MMSE) scores. Brain GMV of the right hippocampus mediated the association between plasma p-tau217 concentrations and MMSE scores. A significant correlation between plasma p-tau181 and MMSE scores was not identified.

CONCLUSION

The findings indicate that p-tau217 is a promising biomarker for central processes affecting brain GMV and cognitive function. This may provide potential targets for future intervention and treatment of tau-targeting therapies in the early stages of AD.

Relationship between sarcopenia and sleep status in female patients with mild to moderate Alzheimer's disease

BACKGROUND

Sleep disorders and sarcopenia could contribute to the development of Alzheimer's disease (AD), which are risk factors that rapidly deteriorate cognitive functions. However, few studies have evaluated the relationship between sarcopenia and sleep disorders in female AD patients, who have a higher prevalence than male patients. This study aimed to investigate the relationship between sarcopenia and sleep status in female patients with mild to moderate AD.

METHODS

This cross-sectional study recruited 112 female outpatients aged between 60 and 85 years. Demographic characteristics, appendicular skeletal muscle mass index (ASMI), grip strength, and gait speed were assessed. Sarcopenia was diagnosed according to criteria of the Asian Working Group for Sarcopenia. Pittsburgh Sleep Quality Index (PSQI) assessed sleep variables. Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) assessed cognitive function. Binary logistic regression models explored the relationship between sleep variables and cognitive function and sarcopenia, adjusting for potential cofounders.

RESULTS

The outpatients were divided into 36 AD patients with sarcopenia (ADSa) and 76 AD patients without sarcopenia (ADNSa), with a prevalence of 32.1%. ADSa had lower ASMI, weaker grip strength, slower gait speed, a higher incidence of poor sleep quality and poorer cognitive function. Multivariate binary logistic regression analysis showed that high total scores of PSQI (odds ratio (OR) = 1.13), poor sleep quality (OR = 2.73), poor subjective sleep quality (OR = 1.83), low MMSE (OR = 0.77) and MoCA (OR = 0.76) scores were associated with high odds of sarcopenia. Compared to sleep time ≤ 15 min, >60 min (OR = 5.01) were associated with sarcopenia. Sleep duration <6 h (OR = 3.99), 8-9 h (OR = 4.48) and ≥9 h (OR = 6.33) were associated with sarcopenia compared to 7-8 h.

CONCLUSIONS

More sleep symptoms and cognitive impairment exist in female patients with sarcopenia. The higher total scores of PSQI, poorer subjective sleep quality, longer sleep latency, excessive and insufficient sleep duration and poorer cognitive function are associated with higher odds of sarcopenia in female patients with mild to moderate AD.

Pathogenesis, Animal Models, and Drug Discovery of Alzheimer's Disease

Alzheimer's disease (AD), the most common cause of dementia, is a chronic neurodegenerative disease induced by multiple factors. The high incidence and the aging of the global population make it a growing global health concern with huge implications for individuals and society. The clinical manifestations are progressive cognitive dysfunction and lack of behavioral ability, which not only seriously affect the health and quality of life of the elderly, but also bring a heavy burden to the family and society. Unfortunately, almost all the drugs targeting the classical pathogenesis have not achieved satisfactory clinical effects in the past two decades. Therefore, the present review provides more novel ideas on the complex pathophysiological mechanisms of AD, including classical pathogenesis and a variety of possible pathogenesis that have been proposed in recent years. It will be helpful to find out the key target and the effect pathway of potential drugs and mechanisms for the prevention and treatment of AD. In addition, the common animal models in AD research are outlined and we examine their prospect for the future. Finally, Phase I, II, III, and IV randomized clinical trials or on the market of drugs for AD treatment were searched in online databases (Drug Bank Online 5.0, the U.S. National Library of Medicine, and Alzforum). Therefore, this review may also provide useful information in the research and development of new AD-based drugs.

Gender differences in the modifying effect of living arrangements on the association of sleep quality with cognitive function among community-dwelling older adults: a cross-sectional study

Background

Sleep quality is considered to be associated with cognitive function for older adults, but little is known about whether living with others can buffer mild cognitive impairment in older adults with poor sleep quality. The objective of this study was to examine the role of living arrangements in sleep quality and cognitive function among older adults aged 65 and over.

Methods

2,859 older adults over 65 years old were selected by using multi-stage stratified sampling method. Cognitive function and sleep quality were measured using Mini-Mental State Examination (MMSE) and Pittsburgh Sleep Quality Index (PSQI). Binary logistic regression was performed to examine the relationship between sleep quality and mild cognitive impairment, and the interaction effects of sleep quality and living arrangements on mild cognitive impairment stratified by gender.

Results

Poor sleep quality was associated with mild cognitive impairment among men and women regardless of living arrangements. The significantly protective role of living with others in reducing the incidence of mild cognitive impairment was found in men with poor sleep quality, but not in women.

Conclusion

Targeted support for older adults with poor sleep quality may be effective in preventing mild cognitive impairment, and gender differences should be taken into account when promoting cohabitations.

Long-term care insurance, mental health of the elderly and its spillovers

The paper studies the effects of the long-term care insurance (LTCI) program in China on the mental health of older adults and the wellbeing of their families. We employ the staggered difference-in-differences approach based on the LTCI pilots from 2015 to 2017. First, we find the LTCI program improves older adults' happiness and reduces depression symptoms significantly. The effects on the improvement in memory and cognition are associated with the elderly with activities of daily living-related need for care. Second, the effects of LTCI are partially mediated through providing community services, relieving care burdens, and reducing the incidence of diseases. More importantly, LTCI coverage improves caregivers' physical health and social activities, reflecting its welfare spillover effects. Furthermore, the relationship between LTCI and mental health differs due to the difference in LTCI designs and older adults' demographic characteristics. This presents a need to consider mental health in the services and evaluation criteria of LTCI.

Expanding Arsenal against Neurodegenerative Diseases Using Quercetin Based Nanoformulations: Breakthroughs and Bottlenecks

Quercetin (Qu), a dietary flavonoid, is obtained from many fruits and vegetables such as coriander, broccoli, capers, asparagus, onion, figs, radish leaves, cranberry, walnuts, and citrus fruits. It has proven its role as a nutraceutical owing to numerous pharmacological effects against various diseases in preclinical studies. Despite these facts, Qu and its nanoparticles are less explored in clinical research as a nutraceutical. The present review covers various neuroprotective actions of Qu against various neurodegenerative diseases (NDs) such as Alzheimer's, Parkinson's, Huntington's, and Amyotrophic lateral sclerosis. A literature search was conducted to systematically review the various mechanistic pathways through which Qu elicits its neuroprotective actions and the challenges associated with raw Qu that compromise therapeutic efficacy. The nanoformulations developed to enhance Qu's therapeutic efficacy are also covered. Various ongoing/completed clinical trials related to Qu in treating various diseases, including NDs, are also tabulated. Despite these many successes, the exploration of research on Qu-loaded nanoformulations is limited mostly to preclinical studies, probably due to poor drug loading and stability of the formulation, time-consuming steps involved in the formulation, and their poor scale-up capacity. Hence, future efforts are required in this area to reach Qu nanoformulations to the clinical level.

Challenges of conducting of online educational programs for family caregivers of people with dementia living at home: An integrative review

Objectives

This integrative review aimed to understand the challenges of conducting online educational programs for family caregivers of people with dementia by focusing on the components and design of them.

Methods

Following Whittemore & Knafl's five-step method, seven databases were systematically searched. The Mixed Methods Appraisal Tool was used to evaluate the quality of the studies.

Results

Of the 25,256 articles identified, 49 studies were included. Limitations in components (including useless or repetitive information, incomplete access to dementia-related information, the impact of components related to culture or ethnicity or gender) and in the format of delivered information (including less interaction, time schedule limitations and preference for traditional forms of delivery of information) make it more challenging to conduct online educational programs. Additionally, implementation constraints such as technical problems, poor computer literacy, and fidelity assessment are challenges that cannot be ignored.

Conclusions

Insight into the challenges of online educational programs for family caregivers of people with dementia can help guide researchers in constructing the optimal online educational program. Incorporating cultural specificity, considering structured construction strategies, optimizing interaction design, and increasing fidelity assessment may contribute to the conduct of online educational programs.

A health promoting-lifestyle prediction model for dementia prevention among chinese adults: based on the health belief model

BACKGROUND

People's health belief is an important factor affecting health behavior. However, there has been little use of the health belief model (HBM) in determining the pathway effect of patients' beliefs on health behavior in dementia prevention in China. The aim of our study was to evaluate the impact of dementia prevention beliefs on health promoting lifestyle among Chinese adults.

METHODS

A cross-sectional study was conducted on line by convenience sampling from January to March 2020. A survey about dementia prevention knowledge, health belief of dementia prevention and health-promoting lifestyle was completed by 1201 adults in China. Data was analyzed using a structural equation model with the analysis of moment program.

RESULTS

The participants were aged 40.50 ± 12.72 years. About 70.3% of participants were female. The purposed model fit the data from the study well. Perceived barriers (total effect-0.322, P < 0.01) and perceived susceptibility (total effect -0.242, P < 0.01) had negative effects on lifestyle. Self-efficacy had promoting effects on lifestyle (total effect 0.207, P < 0.01). Perceived severity had positive effects both on perceived benefits (total effect 0.137, P < 0.01) and perceived barriers (total effect 0.202, P < 0.01), which had a contradictory effect in the formation of health belief. Perceived benefits, cues to action and self-efficacy played a partial mediating role between knowledge and health behavior. The belief of changing lifestyle to reduce the risk of dementia could explain 24.5% of health behavior (P < 0.05).

CONCLUSIONS

The findings indicate that in dementia prevention, dementia prevention health belief has important influences on health behavior. Community medical staff can develop targeted dementia prevention interventions based on the health belief model in the future.

Indoor air pollution from solid fuels use, inflammation, depression and cognitive function in middle-aged and older Chinese adults

BACKGROUND

Few studies have focused on the influence of indoor air pollution on depression and cognitive impairment; besides, the underlying mechanism is not well-established.

OBJECTIVE

This study aimed to fill the above gaps by exploring the underlying influence mechanism of solid fuel use, the major cause of indoor air pollution, with the risk of depression and cognitive impairment.

METHODS

This data came from China Health and Retirement Longitudinal Study (CHARLS) 2015 dataset. Self-reported household cooking fuels were collected and categorized as clean fuels and solid fuels. High-sensitivity C-reactive protein (CRP) and white blood cells (WBC) were used to measure inflammation. Depression and cognitive function were assessed by using standardized questionnaires.

RESULTS

Respondents had an average Center for Epidemiologic Studies Depression Scale (CESD-10) scores of 7.68 (SD = 6.14) and cognitive function scores of 15.97 (SD = 4.84). In the whole sample, 36.4 % of respondents used solid fuels use, but this proportion was much greater among those living in rural areas (78.38 %). Compared with clean fuel users, solid fuel users had more depression and worse cognitive function. After adjusting for confounders, indoor air pollution was significantly associated with depression and cognitive function respectively (β = -0.444, p < 0.001; β = 0.656, p < 0.001). Indoor air pollution was significantly related to the WBC (β = 0.170, p < 0.01), but not for the CRP. The WBC mediated the association between indoor air pollution and depression (β = 0.026, p < 0.01).

CONCLUSION

In conclusion, solid fuel use was significantly associated with a higher risk of depression and cognitive impairment. Furthermore, we found that solid fuel use influences depression partly via the inflammatory profile.

Feasibility of a Culturally Specific DEmentia Competence Education for Nursing Home Taskforce (DECENT) Programme: A Mixed-Method Approach

Although educational resources have been developed to build staff's dementia care competence in Western culture, their applicability and cultural relevance to the Chinese population are questionable. To address this gap, the DEmentia Competence Education for Nursing home Taskforce (DECENT) programme was developed and tailored to Chinese staff. This study aimed to evaluate the feasibility and preliminary effects of the DECENT programme. A one-group pretest-posttest study, embedded with a qualitative component, was conducted among 12 healthcare professionals. The DECENT programme comprised eight topics covering essential competencies in dementia care. It was delivered face-to-face by a qualified educator once per week for 60-90 min over 8 weeks. Outcomes were measured at baseline and immediately post-intervention. A satisfaction survey and individual interviews were conducted post-intervention to understand participants' perceptions and experience with the intervention. Nine participants finished the post-intervention assessment. Except for staff's attitudes towards people with dementia, quantitative findings generally demonstrated positive changes following the intervention. Three categories were identified from the qualitative data: well-developed programme, perceived benefits, and barriers. The findings showed that the DECENT programme is feasible and is perceived by nursing home staff as relevant and useful to daily practice. A larger-scale study is needed to evaluate its effectiveness.

Understanding the Intricate Role of Exosomes in Pathogenesis of Alzheimer's Disease

Alzheimer's disease causes loss of memory and deterioration of mental abilities is utmost predominant neurodegenerative disease accounting 70-80% cases of dementia. The appearance of plaques of amyloid-β and neurofibrillary tangles in the brain post-mortems of Alzheimer's patients established them as key participants in the etiology of Alzheimer's disease. Exosomes exist as extracellular vesicles of nano-size which are present throughout the body. Exosomes are known to spread toxic hyperphosphorylated tau and amyloid-β between the cells and are linked to the loss of neurons by inducing apoptosis. Exosomes have progressed from cell trashcans to multifunctional organelles which are involved in various functions like internalisation and transmission of macromolecules such as lipids, proteins, and nucleic acids. This review covers current findings on relationship of exosomes in biogenesis and angiogenesis of Alzheimer's disease and functions of exosomes in the etiology of AD. Furthermore, the roles of exosomes in development, diagnosis, treatment, and its importance as therapeutic targets and biomarkers for Alzheimer's disease have also been highlighted.

Psychological resilience, activities of daily living, and cognitive functioning among older male Tekun adults in rural long-term care facilities in China

Most of the rural long-term care (LTC) facilities in China are ill-equipped to manage the physical and psychological needs of older residents with dementia. These facilities mostly consist of older male Tekun (socially and economically vulnerable) adults. Preventing or delaying the onset of dementia is especially crucial for these older Tekun adults. A sample of 711 older male Tekun adults from rural LTC facilities in the Anhui province of China was used to investigate the association between psychological resilience and cognitive functioning, and to examine the moderating effect of activities of daily living (ADLs) on that association. Linear and quantile regression found that resilience was positively associated with cognitive functioning for the total sample, with a greater effect among those with a lower level of cognitive functioning. The benefit of resilience on cognitive functioning was observed only in participants with disability in ADLs. Our findings present evidence in support of interventions to foster psychological resilience and potentially improve cognitive functioning among vulnerable older adults. Resilience-promoting intervention is a strength-based approach that aligns with social work values and can be used in practice. The implications for social work practice were discussed.