Midlife vascular risk factors and Alzheimer's disease in later life: longitudinal, population based study

Association between social networking and dementia: A systematic review of observational studies

Poor social networking (SN) is associated with the development of cognitive impairment and dementia. Our objective was to perform a systematic review of the evidence on the associations between SN and the incidence of dementia, disease pathology, level of cognition, and brain structure. Bibliographic databases (PubMed, Embase, Cochrane Library, CINAHL) and additional sources (Open Gray, Google Scholar, manual searches) were screened through November 30, 2024. Observational studies assessing the SN-dementia link were selected, with data extraction and bias evaluation performed independently by two authors via the PRISMA checklist and Newcastle-Ottawa Scale. We included 17 observational studies (355 initially screened), involving 20,678 participants aged 40-90 years, published between 2000 and 2024. Studies have utilized various SN assessment tools and cognitive measures, including the MMSE and MoCA. Poor SN was consistently associated with increased risks of dementia, cognitive decline, and severe disease pathology, particularly Alzheimer's disease (AD). Larger and more integrated SNs were linked to better cognitive resilience and lower conversion rates from mild cognitive impairment (MCI) to dementia. One study on frontotemporal dementia (FTD) indicated that the SN might mitigate cortical atrophy. SN size and density are also correlated with favorable structural brain changes, such as greater gray matter volume. This review highlights SN as a modifiable factor in dementia risk. However, its role in non-AD dementia, particularly FTD, requires further investigation. Future research should include more culturally diverse and methodologically robust studies. Randomized controlled trials will be important to determine whether intervention to expand social networks decreases incidence of progression of dementia.

LDL Exposure Disrupts Mitochondrial Function and Dynamics in a Hippocampal Neuronal Cell Line

Hypercholesterolemia has been associated with cognitive dysfunction and neurodegenerative diseases. Moreover, this metabolic condition disrupts the blood-brain barrier, allowing low-density lipoprotein (LDL) to enter the central nervous system. Thus, we investigated the effects of LDL exposure on mitochondrial function in a mouse hippocampal neuronal cell line (HT-22). HT-22 cells were exposed to human LDL (50 and 300 μg/mL) for 24 h. After this, intracellular lipid droplet (LD) content, cell viability, cell death, and mitochondrial parameters were assessed. We found that the higher LDL concentration increases LD content compared with control. Both concentrations increased the number of Annexin V-positive cells, indicating apoptosis. Moreover, in mitochondrial parameters, the LDL exposure on hippocampal neuronal cell line leads to a decrease in mitochondrial complexes I and II activities in both concentrations tested and a reduction in Mitotracker™ Red fluorescence and Mitotracker™ Red and Mitotracker™ Green ratio in the higher concentration, indicating mitochondrial impairment. The LDL incubation induces mitochondrial superoxide production and decreases superoxide dismutase activity in the lower concentration in HT-22 cells. Finally, LDL exposure increases the expression of genes associated with mitochondrial fusion (OPA1 and mitofusin 2) in the lower concentration. In conclusion, our findings suggest that LDL exposure induces mitochondrial dysfunction and modulates mitochondrial dynamics in the hippocampal neuronal cells.

HMGCR Inhibitor Restores Mitochondrial Dynamics by Regulating Signaling Cascades in a Rodent Alzheimer's Disease Model

Atorvastatin an HMGCR inhibitor may play a role in enhancing spatial and long-term memory and combating anxious behavior deficits induced by Aβ1-42. Behavioral deficit studies, immunoblotting for the antioxidant/apoptotic protein expression, flow cytometry (FACS) for mitochondrial ROS, membrane potential (▲ψm), and histopathological alterations were performed against Aβ1-42 toxicity. Aβ1-42 was infused directly into the brain through i.c.v for the establishment of the AD model. Atorvastatin (ATOR) was administered orally and was used to treat AD in adult male Wistar rats aged between 200 and 250 g. We confirmed that ATOR administration significantly attenuates the Aβ1-42-induced cognitive decline targeted mitochondrial-mediated age-dependent disease progression. Nrf2 stabilizes to interact SOD2 antioxidant enzyme, allowing transcriptional activity by the steep increase in ▲ψm and a reduction in ROS by activating mitochondrial superoxide scavenger and Nrf2-dependent pathway. These findings confirmed that ATOR has the potential efficacy to modulate the interference in cognitive decline induced by Aβ1-42.

Double product is longitudinally associated with reduced cognitive function in type 2 diabetes with insights from cross-lagged panel analysis and mediation by leucine-rich α-2-glycoprotein 1

BackgroundElevated systolic blood pressure (SBP) and resting heart rate (RHR) contribute to pathogenesis of diabetic complications. They increase inflammation which can upregulate leucine-rich α-2-glycoprotein 1 (LRG1), an emerging biomarker of cognitive decline.ObjectiveTo examine association between double product (DP, derived from multiplying SBP and RHR) and cognitive function in type 2 diabetes (T2D), with possible mediation by plasma LRG1.MethodsIn this prospective cohort of 1319 patients (mean age 62.5 ± 7.3), plasma LRG1 was measured with enzyme-linked immunosorbent assay. Cognitive function was assessed using Repeatable Battery for Assessment of Neuropsychological Status (RBANS). Cross-lagged panel analysis was done to examine temporal relationship between DP and cognitive function.ResultsBaseline DP was associated with lower baseline RBANS total score (adjusted coefficient = -2.43; 95%CI -4.76, -0.10; p = 0.041). 586 patients were followed up to 8.6 years. Baseline DP was associated with follow-up RBANS total score (adjusted coefficient = -3.80; 95%CI -6.51, -1.10; p = 0.006). It was also associated with lower follow-up RBANS scores in immediate memory and delayed memory with adjusted coefficients -4.38 (95%CI -8.49, -0.28; p = 0.036) and -5.12 (95%CI -9.88, -0.35; p = 0.035) respectively. In cross-lagged panel analysis, standardized effect size of baseline DP on follow-up RBANS total score (β = -0.08; p = 0.002) was larger than that of baseline RBANS total score on follow-up DP (β = -0.04; p = 0.266). LRG1 accounted for 14.7% of the association in mediation analysis (p = 0.035).ConclusionsDP was independently associated with cognitive function with possible mediation by LRG1. DP preceded decline in cognitive function. DP may be potential intervention and monitoring target for prevention of cognitive impairment and possibly Alzheimer's disease in T2D.

Hypercholesterolemia, oxidative stress, and low-grade inflammation: a potentially dangerous scenario to blood-brain barrier

For more than a century, hypercholesterolemia has been linked to atherosclerotic cardiovascular disease. Notably, this metabolic condition has also been pointed out as a risk factor for neurodegenerative diseases, such as Alzheimer's disease (AD). Oxidative stress seems to be the connective factor between hypercholesterolemia and cardio and neurological disorders. By disturbing redox homeostasis, hypercholesterolemia impairs nitric oxide (NO) availability, an essential vasoprotective element, and jeopardizes endothelial function and selective permeability. The central nervous system (CNS) is partially protected from peripheral insults due to an arrangement between endothelial cells, astrocytes, microglia, and pericytes that form the blood-brain barrier (BBB). The endothelial dysfunction related to hypercholesterolemia increases the risk of developing cardiovascular diseases and also initiates BBB breakdown, which is a cause of brain damage characterized by neuroinflammation, oxidative stress, mitochondrial dysfunction, and, ultimately, neuronal and synaptic impairment. In this regard, we reviewed the mechanisms by which hypercholesterolemia-induced oxidative stress affects peripheral vessels, BBB, and leads to memory deficits. Finally, we suggest oxidative stress as the missing link between hypercholesterolemia and dementia.

Cerebral perfusion and gray matter volume alterations associated with cognitive impairment in metabolic syndrome with cerebral small vessel disease

Objective

Metabolic syndrome (MetS) combined with cerebral small vessel disease (CSVD) is associated with cognitive dysfunction. However, the underlying mechanisms remain poorly understood. This study investigated the roles of brain perfusion and gray matter volume (GMV) in cognitive dysfunction in patients with MetS combined with CSVD (MetS-CSVD).

Methods

This study enrolled 180 MetS patients and 86 healthy controls (HCs). Patients with MetS were categorized into MetS without CSVD (MetS-NCSVD) (n = 58) and MetS with CSVD (MetS-CSVD) (n = 122) groups. All participants underwent laboratory tests, neuropsychological assessments, 3D pseudo-continuous arterial spin labeling (3D-PCASL), and magnetic resonance imaging scans with voxel-based morphometry (VBM). Cerebral blood flow (CBF), GMV, and clinical scales were analyzed for correlations in regions of interest (ROIs). The relationships among cognitive performance, CBF, and GMV were evaluated using partial correlation analysis and multivariable linear regression analysis (MLRA). Mediation analysis was performed to investigate the roles of CBF and GMV in the association between CSVD scores and cognitive performance.

Results

Compared to the MetS-NCSVD and HC groups, the MetS-CSVD group displayed significantly reduced perfusion and GMV in the frontal and temporal lobes. Partial correlation analysis revealed that CBF and GMV in the frontotemporal lobe were strongly associated with overall cognitive function, executive function, and language function in the MetS-CSVD group. MLRA identified the CSVD score as the sole independent factor negatively associated with cognitive performance. Mediation analysis revealed that CBF and GMV in the frontal lobes mediated the relationship between the CSVD score and overall cognitive and executive function.

Conclusion

CBF and GMV were strongly associated with cognitive performance. CSVD, rather than individual components of MetS, mediated cognitive impairment in patients with MetS-CSVD. CSVD likely contributes indirectly to cognitive impairment through its effects on CBF and GMV in these patients.

Federated learning with multi-cohort real-world data for predicting the progression from mild cognitive impairment to Alzheimer's disease

INTRODUCTION

Leveraging routinely collected electronic health records (EHRs) from multiple health-care institutions, this approach aims to assess the feasibility of using federated learning (FL) to predict the progression from mild cognitive impairment (MCI) to Alzheimer's disease (AD).

METHODS

We analyzed EHR data from the OneFlorida+ consortium, simulating six sites, and used a long short-term memory (LSTM) model with a federated averaging (FedAvg) algorithm. A personalized FL approach was used to address between-site heterogeneity. Model performance was assessed using the area under the receiver operating characteristic curve (AUC) and feature importance techniques.

RESULTS

Of 44,899 MCI patients, 6391 progressed to AD. FL models achieved a 6% improvement in AUC compared to local models. Key predictive features included body mass index, vitamin B12, blood pressure, and others.

DISCUSSION

FL showed promise in predicting AD progression by integrating heterogeneous data across multiple institutions while preserving privacy. Despite limitations, it offers potential for future clinical applications.

HIGHLIGHTS

We applied long short-term memory and federated learning (FL) to predict mild cognitive impairment to Alzheimer's disease progression using electronic health record data from multiple institutions. FL improved prediction performance, with a 6% increase in area under the receiver operating characteristic curve compared to local models. We identified key predictive features, such as body mass index, vitamin B12, and blood pressure. FL shows effectiveness in handling data heterogeneity across multiple sites while ensuring data privacy. Personalized and pooled FL models generally performed better than global and local models.

Longitudinal Analysis of Electronic Health Records Reveals Medical Conditions Associated with Subsequent Alzheimer's Disease Development

Background

Several health conditions are known to increase the risk of Alzheimer's disease (AD). We aim to systematically identify medical conditions that are associated with subsequent development of AD by leveraging the growing resources of electronic health records (EHRs).

Methods

This retrospective cohort study used de-identified EHRs from two independent databases (MarketScan and VUMC) with 153 million individuals to identify AD cases and age- and gender-matched controls. By tracking their EHRs over a 10-year window before AD diagnosis and comparing the EHRs between AD cases and controls, we identified medical conditions that occur more likely in those who later develop AD. We further assessed the genetic underpinnings of these conditions in relation to AD genetics using data from two large-scale biobanks (BioVU and UK Biobank, total N=450,000).

Results

We identified 43,508 AD cases and 419,455 matched controls in MarketScan, and 1,320 AD cases and 12,720 matched controls in VUMC. We detected 406 and 102 medical phenotypes that are significantly enriched among the future AD cases in MarketScan and VUMC databases, respectively. In both EHR databases, mental disorders and neurological disorders emerged as the top two most enriched clinical categories. More than 70 medical phenotypes are replicated in both EHR databases, which are dominated by mental disorders (e.g., depression), neurological disorders (e.g., sleep orders), circulatory system disorders (e.g. cerebral atherosclerosis) and endocrine/metabolic disorders (e.g., type 2 diabetes). We identified 19 phenotypes that are either associated with individual risk variants of AD or a polygenic risk score of AD.

Conclusions

In this study, analysis of longitudinal EHRs from independent large-scale databases enables robust identification of health conditions associated with subsequent development of AD, highlighting potential opportunities of therapeutics and interventions to reduce AD risk.

Cardiovascular Health and Biomarkers of Neurodegenerative Disease in Older Adults

Importance

Cardiovascular health (CVH), defined by the American Heart Association as Life's Simple 7 to promote a healthy lifestyle and manage vascular risk factors, has been associated with a low risk of Alzheimer disease and less vascular dementia. However, the association between CVH and biomarkers of neurodegeneration remains less understood.

Objective

To investigate the association of CVH with serum biomarkers of neurodegeneration, including neurofilament light chain (NfL) and total tau (t-tau).

Design, Setting, and Participants

This cohort study was conducted within the biracial, population-based Chicago Health and Aging Project (CHAP) of adults aged 65 years or older between 1993 and 2012. Participants who had measured serum NfL and t-tau levels and data on all components of the CVH score were included. The statistical analysis was conducted from April 10 to September 26, 2024.

Exposure

The CVH score includes 7 components: a healthy diet; regular exercise; normal body mass index; nonsmoking status; and the absence of dyslipidemia, diabetes, and hypertension. The scores were divided into 3 groups from lowest to highest CVH (0-6 points, 7-9 points, and 10-14 points).

Main Outcomes and Measures

The main outcome was the association of CVH score with serum biomarkers of NfL and t-tau as measured using linear regression and mixed-effects models.

Results

A total of 1018 CHAP participants were included in the analysis (mean [SD] age, 73.1 [6.1] years; 625 female [61.4%]; 610 Black or African American [59.9%] and 408 White [40.1%]). Participants with a high CVH score (ie, 10-14 points) were predominantly White (151 [64.3%]) and had a higher education (mean [SD], 13.6 [3.7] years). Compared with participants with low CVH scores (ie, 0-6 points), those with CVH scores of 10 to 14 points had significantly lower serum levels of NfL (relative difference, -18.9%; β = -0.091; SE, 0.025). A higher CVH score was associated with a slower annual increase in NfL levels as participants aged (relative difference in rate, -1.7%; β = -0.008; SE, 0.004). Cardiovascular health was not associated with serum levels of t-tau.

Conclusions and Relevance

These findings suggest that promoting CVH in older adults may help alleviate the burden of neurodegenerative diseases, particularly among Black adults, who are known to experience a higher prevalence of cardiovascular disease.

Assessing the role of vascular risk factors in dementia: Mendelian randomization meta-analysis and comparison with observational estimates

Background

Although observational studies demonstrate that higher levels of vascular risk factors are associated with an increased risk of dementia, these associations might be explained by confounding or other biases. Mendelian randomization (MR) uses genetic instruments to test causal relationships in observational data. We sought to determine if genetically predicted modifiable risk factors (type 2 diabetes mellitus, low density lipoprotein cholesterol, high density lipoprotein cholesterol, total cholesterol, triglycerides, systolic blood pressure, diastolic blood pressure, body mass index, and circulating glucose) are associated with dementia by meta-analysing published MR studies. Secondary objectives were to identify heterogeneity in effect estimates across primary MR studies and to compare meta-analysis results with observational studies.

Methods

MR studies were identified by systematic search of Web of Science, OVID and Scopus. We selected primary MR studies investigating the modifiable risk factors of interest. Only one study from each cohort per risk factor was included. A quality assessment tool was developed to primarily assess the three assumptions of MR for each MR study. Data were extracted on study characteristics, exposure and outcome, effect estimates per unit increase, and measures of variation. Effect estimates were pooled to generate an overall estimate, I 2 and Cochrane Q values using fixed-effect model.

Results

We screened 5211 studies and included 12 primary MR studies after applying inclusion and exclusion criteria. Higher genetically predicted body mass index was associated with a higher odds of dementia (OR 1.03 [1.01, 1.05] per 5 kg/m 2 increase, one study, p=0.00285). Fewer hypothesized vascular risk factors were supported by estimates from MR studies than estimates from meta-analyses of observational studies.

Conclusion

Genetically predicted body mass index was associated with an increase in risk of dementia.

Age-related differences in agility are related to both muscle strength and corticospinal tract function

Agility is essential for "healthy" aging, but neuromuscular contributions to age-related differences in agility are not entirely understood. We recruited healthy (n = 32) non-athletes (30-84 years) to determine: (1) if aging is associated with agility and (2) whether muscle strength or corticospinal tract function predicts agility. We assessed muscle strength via a validated knee extension test, corticospinal tract function via transcranial magnetic stimulation, and agility via spatiotemporal values (i.e., leg length-adjusted hop length and hop length variability) collected during a novel propulsive bipedal hopping (agility) task on an electronic walkway. Pearson correlation revealed aging is associated with leg length-adjusted hop length (r = -0.671, p < 0.001) and hop length variability (r = 0.423, p = 0.016). Further, leg length-adjusted hop length and hop length variability correlated with quadriceps strength (r = 0.581, p < 0.001; r = -0.364, p = 0.048) and corticospinal tract function (r = -0.384, p = 0.039; r = 0.478, p = 0.007). However, hierarchical regressions indicated that, when controlling for sex, muscle strength only predicts leg length-adjusted hop length (R2 = 0.345, p = 0.002), whereas corticospinal tract function only predicts hop length variability (R2 = 0.239, p = 0.014). Therefore, weaker quadriceps decrease the distance hopped, and deteriorating corticospinal tract function increases variability in hop length.

The cerebral blood flow response to neuroactivation is reduced in cognitively normal men with β-amyloid accumulation

BACKGROUND

Accumulation of β-amyloid (Aβ) in the brain is a hallmark of Alzheimer's Disease (AD). Cerebral deposition of Aβ initiates deteriorating pathways which eventually can lead to AD. However, the exact mechanisms are not known. A possible pathway could be that Aβ affects the cerebral vessels, causing inadequate cerebrovascular function. In the present study, we examined if Aβ accumulation is associated with a reduced cerebral blood flow response (CBF) to neuronal activation by visual stimulation (ΔCBFVis.Act.) in cognitively normal subjects from the Metropolit Danish Male Birth Cohort.

METHODS

64 subjects participated in the present study. ΔCBFVis.Act. was measured using arterial spin labelling (ASL) combined with blood-oxygen-level-dependent (BOLD) MRI. Neuronal activation was obtained by visual stimulation by a flickering checkerboard presented on a screen in the MRI-scanner. Brain Aβ accumulation and cerebral glucose metabolism were assessed by PET imaging using the radiotracers [11C]Pittsburgh Compound-B (PiB) and [18F]Fluorodeoxyglucose (FDG), respectively. Cortical thickness was measured from structural MRI.

RESULTS

ΔCBFVis.Act. correlated negatively ( β = -32.1 [95% confidence interval (CI): -60.2; -4.1], r = -0.30, p = 0.025) with PiB standardized uptake value ratio (SUVr) in the brain regions activated by visual stimulation. ΔCBFVis.Act. did not correlate with FDG SUVr ( β = 1.9 [CI: -23.8; 27.6], r = 0.02, p = 0.88) or cortical thickness ( β = 10.3 [CI: -8.4; 29.0], r = 0.15, p = 0.27) in the activated brain regions. Resting CBF did not correlate with PiB SUVr neither in the regions activated by visual stimulation ( β = -17.8 [CI:-71.9; 36.2], r =- 0.09, p = 0.51) nor in the remaining cortex ( β = 5.2 [CI:-3.9; 14.2], r = 0.15, p = 0.26).

CONCLUSION

We found a correlation between high PiB SUVr and reduced CBF response to neuronal activation, indicating a link between Aβ accumulation and impaired cerebrovascular function. The impairment was not associated with cortical thinning or hypometabolism, suggesting that Aβ accumulation affecting brain vessel function could be a very early pathology leading to neurodegenerative disease.

Characterizing vascular function in mouse models of Alzheimer's disease, atherosclerosis, and mixed Alzheimer's and atherosclerosis

Significance

Alzheimer's disease does not occur in isolation, and there are many comorbidities associated with the disease, especially diseases of the vasculature. Atherosclerosis is a known risk factor for the subsequent development of Alzheimer's disease; therefore, understanding how both diseases interact will provide a greater understanding of co-morbid disease progression and aid the development of potential new treatments.

Aim

We characterize hemodynamic responses and cognitive performance in APP/PS1 Alzheimer's mice, atherosclerosis mice, and a mixed disease group (APP/PS1 and atherosclerosis) between the ages of 9 and 12 months.

Approach

Whisker-evoked hemodynamic responses and recognition memory were assessed in awake mice, immunohistochemistry to assess amyloid pathology, and histology to characterize atherosclerotic plaque load.

Results

We observed hemodynamic deficits in atherosclerosis mice (versus Alzheimer's, mixed disease, or wild-type mice), with reduced short-duration stimulus-evoked hemodynamic responses occurring when there was no concurrent locomotion during the stimulation period. Mixed Alzheimer's and atherosclerosis models did not show differences in amyloid beta coverage in the cortex or hippocampus or atherosclerotic plaque burden in the aortic arch vs relevant Alzheimer's or atherosclerosis controls. Consistent with the subtle vascular deficits and no pathology differences, we also observed no difference in performance on the object recognition task across groups.

Conclusions

These results emphasize the importance of experimental design for characterizing vascular function across disease groups, as locomotion and stimulus duration impacted the ability to detect differences between groups. Although atherosclerosis did reduce hemodynamic responses, these were recovered in the presence of co-occurring Alzheimer's disease, which may provide targets for future studies to explore the potentially contrasting vasodilatory mechanisms these diseases impact.

Causal Associations of Cognitive Reserve and Hierarchical Aging-Related Outcomes: A Two-Sample Mendelian Randomization Study

PURPOSE

Two-sample Mendelian randomization methods were used to explore the causal effects of cognitive reserve proxies, such as educational attainment, occupational attainment, and physical activity (PA), on biological (leukocyte telomere length), phenotypic (sarcopenia-related features), and functional (frailty index and cognitive performance) aging levels.

RESULTS

Educational attainment had a potential protective effect on the telomere length (β = 0.10, 95% CI: 0.08-0.11), sarcopenia-related features (β = 0.04-0.24, 95% CI: 0.02-0.27), frailty risk (β = -0.31, 95% CI: -0.33 to -0.28), cognitive performance (β = 0.77, 95% CI: 0.75-0.80). Occupational attainment was causally related with sarcopenia-related features (β = 0.07-0.10, 95% CI: 0.05-0.14), and cognitive performance (β = 0.30, 95% CI: 0.24-0.36). Device-measured PA was potentially associated with one sarcopenia-related feature (β = 0.14, 95% CI: 0.03-0.25).

CONCLUSIONS

Our findings support the potential causality of educational attainment on biological, phenotypic, and functional aging outcomes, of occupational attainment on phenotypic and functional aging-related outcomes, and of PA on phenotypic aging-related outcomes.

Advantages and challenges of using arterial spin labelling MRI to monitor cerebral blood flow in multi-centre clinical trials of neurodegenerative disease: Experience from the RADAR study

Arterial spin labelling (ASL) enables non-invasive quantification of regional brain perfusion using MRI. ASL was used in the Reducing Pathology in Alzheimer's Disease through Angiotensin TaRgeting (RADAR) multi-centre trial to pilot the assessment of the effects of the anti-hypertension drug losartan on cerebral blood flow (CBF). In the multi-centre setting, disparities in ASL implementation on scanners from different manufacturers lead to inherent differences in measured CBF and its associated parameters (e.g. spatial coefficient of variation (sCoV) of CBF, a proxy of arterial arrival times). In addition, differences in ASL acquisition parameter settings can also affect the measured quantitative perfusion values. In this study, we used data from the RADAR cohort as a case study to evaluate the site-dependent systematic differences of CBF and sCoV, and show that variations in the readout module (2D or 3D) and the post-labelling delay acquisition parameter introduced artifactual group differences. When accounting for this effect in data analysis, we show that it is still possible to combine ASL data across sites to observe the expected relationships between grey matter CBF and cognitive scores. In summary, ASL can provide useful information relating to CBF difference in multi-centre therapeutic trials, but care must be taken in data analysis to account for the inevitable inter-site differences in scanner type and acquisition protocol.

Regional cerebral blood flow reflects both neurodegeneration and microvascular integrity across the Alzheimer's continuum

INTRODUCTION

Alzheimer's disease (AD) typically involves both neurodegenerative and vascular pathologies, each associated with reductions in cerebral blood flow (CBF). However, it remains unclear whether vascular and neural contributions to regional CBF can be differentiated.

METHODS

Using 3D background-suppressed arterial spin labeled perfusion magnetic resonance imaging, we evaluated regional CBF in a cohort of 257 participants across the AD continuum and assessed the impact of risk factors for both AD and small vessel disease (SVD) on regional CBF.

RESULTS

Vascular risk factors (VRFs) were associated with reduced CBF in normal-appearing periventricular white matter, while amyloid positivity was associated with reduced CBF in the posterior cingulate cortex and precuneus. Putative SVD-sensitive regions in white matter exhibited diagnosis-related CBF changes comparable to those in typical AD cortical regions.

DISCUSSION

Spatial patterns of hypoperfusion may differentiate AD and VRF-related effects on regional CBF. Our findings also support the contribution of SVD in AD pathogenesis.

HIGHLIGHTS

We used 3D background-suppressed pCASL MRI to evaluate CBF across the AD continuum. Putative SVD-sensitive regions in white matter exhibited diagnosis-related CBF changes. AD and/or SVD risk correlated with reduced CBF in AD and/or SVD-related regions. VRFs were associated with more widespread CBF reductions than amyloid positivity. Spatial patterns of hypoperfusion may differentiate AD and VRF-related effects.

Association between pathological scar and hypertension: A two-sample Mendelian randomization study

Observational studies have linked pathological scars to hypertension; however, the causality remains ambiguous. In this study, we aimed to explore this issue using Mendelian randomization (MR). We obtained genome-wide association study data for hypertrophic scar and hypertension from the IEU Open genome-wide association study project [hypertension (containing 9851,867 SNPs, observation group of 124,227, and control group of 337,653), hypertrophic scars (containing 16,380,443 SNPs with a sample mass of 207,482), and keloids (containing 24,197,210 SNPs and sample volume of 481,912)]. The inverse variance weighted method and MR-Egger test were used, followed by a sensitivity analysis. With hypertension as the exposure and hypertrophic scar as the outcome, we obtained the IVW analysis results (OR = 0.264, 95% CI = 0.098-0.709, P = .008) and the MR-Egger test results (OR = 0.036, 95% CI = 0.002-0.544, P = .017); for keloid as the outcome, the results of IVW analysis showed OR = 0.592, 95% CI = 0.293-1.195, P = .143. Contrary to the findings of observational studies, our results revealed hypertension as a protective factor against hypertrophic scarring, and was unrelated to keloids.

Standardization in the judgment of line orientation test in elderly people in Northeast Brazil

Aging is generally associated with a decline in cognition when compared to adulthood. The changes most seen are in attention, perception, working memory, short-term memory, free recall, and processing speed. Certain changes in the Judgment of Line Orientation (JLO) test may be present in elderly people.

Objective

The objective of this study was to describe the difference among age, sex, schooling, Mini-Mental State (MMS), and Mini-Mental State Examination (MMSE) when compared to the JLO test in elderly people. The second is to assess the clinical use of the JLO test in elderly people's cognitive decline in Northeast Brazil.

Methods

A cross-sectional, randomized study was carried out on 280 elderly people, between 60 and 89 years old, and the mean age was 69.4 (±6.8 years SD); 73.9% of the females lived in Olinda City, State of Pernambuco, Brazil. Age was stratified every 5 years between 60 and 89 years old, and schooling was divided into four subgroups between illiterate and more than 8 years of schooling. Each participant was submitted to an analysis of age, sex, schooling, risk factors, MMS, modified MMSE, and a JLO test.

Results

There was no statistical difference between the sexes. However, there was a statistical difference when compared to the JLO test and age (p<0.012), schooling (p<0.001), MMS (p<0.001), and modified MMSE (p<0.001).

Conclusion

We observed that with a cutoff point of 18 points, the JLO test is indicated to assess visuospatial and visuoperceptive changes in elderly people in Northeast Brazil.

Non-canonical pathways associated to Amyloid beta and tau protein dyshomeostasis in Alzheimer's disease: A narrative review

Alzheimer's Disease (AD) is the most common form of dementia among elderly people. This disease imposes a significant burden on the healthcare system, society, and economy due to the increasing global aging population. Current trials with drugs or bioactive compounds aimed at reducing cerebral Amyloid beta (Aβ) plaques and tau protein neurofibrillary tangles, which are the two main hallmarks of this devastating neurodegenerative disease, have not provided significant results in terms of their neuropathological outcomes nor met the expected clinical end-points. Ageing, genetic and environmental risk factors, along with different clinical symptoms suggest that AD is a complex and heterogeneous disorder with multiple interconnected pathological pathways rather than a single disease entity. In the present review, we highlight and discuss various non-canonical, Aβ-independent mechanisms, like gliosis, unhealthy dietary intake, lipid and sugar signaling, and cerebrovascular damage that contribute to the onset and development of AD. We emphasize that challenging the traditional "amyloid cascade hypothesis" may improve our understanding of this age-related complex syndrome and help fight the progressive cognitive decline in AD.

Risk of Stroke or Heart Attack in Mild Cognitive Impairment and Subjective Cognitive Impairment

BACKGROUND

The study aimed to identify Mild Cognitive Impairment (MCI) as an alert clinical manifestation of increased probability of major acute vascular events (MVEs), such as Ischemic Stroke and heart attack.

METHODS

In a longitudinal study, 181 (M = 81, F = 100; mean age of 75.8 ± 8.69 years) patients were enrolled and divided into three groups based on diagnosis: Subjective Cognitive Impairment (SCI), amnestic MCI Single Domain (aMCI-SD), and amnestic MCI More Domain (aMCI-MD). Clinical assessment and the presence of vascular risk factors were collected.

RESULTS

The distribution of MVEs showed a higher incidence in the first two years of follow-up of 7.4% in SCI, 12.17% in aMCI-SD, and 8.57% in aMCI-MD. Acute Myocardial Infarction showed a major incidence in one year of follow-up (41%) and in two years of follow-up (29%). Also, Ischemic Stroke showed a major incidence in one year of follow-up (30%) and in two years of follow-up (40%). A statistically significant difference in the progression to dementia was shown (SCI 3.75%; aMCI-SD 10.43%; aMCI-MD 37%; p-value < 0.001).

CONCLUSIONS

MCI is considered an expression of the systemic activation of mechanisms of endothelial damage, representing a diagnosis predictive of increased risk of MVEs.

The association between serum cholesterol levels and mild-to-moderate cognitive impairment in the Suita Study and evidence from other epidemiological studies

BACKGROUND

Serum cholesterols are well-documented markers of cardiovascular diseases; however, their association with cognitive well-being is uncertain. This study investigated the association between serum cholesterol levels and mild-to-moderate cognitive impairment.

METHODS

Epidemiological evidence on the role of total cholesterol (TC), high-density lipoprotein cholesterol (HDLC), non-HDL-C, and low-density lipoprotein cholesterol (LDL-C) in cognitive impairment was highlighted. Then, data from 6216 Japanese individuals, aged ≥50 years, from the Suita Study were analyzed. Mini-Mental State Examination (MMSE) scores <27 and < 24 were used to define cognitive impairment. Logistic regression was used to calculate the odds ratios (ORs) and 95 % confidence intervals (95 % CIs) for cognitive impairment.

RESULTS

Epidemiological studies investigating the association between serum cholesterol and cognitive impairment have shown conflicting findings: elevated risk with certain lipid components in some studies and no association in others. In the Suita Study, HDL-C < 40 mg/dL was associated with cognitive impairment: ORs (95 % CIs) = 1.36 (1.08, 1.72) for MMSE <27 and 1.61 (1.00, 2.60) for MMSE <24. Non-HDL-C ≥ 200 mg/dL was also associated with cognitive impairment: ORs (95 % CIs) = 1.53 (1.02, 2.31) for MMSE <27 and 1.80 (1.16, 2.79) for MMSE <24. No such associations were detected with TC.

CONCLUSION

While epidemiological evidence remains inconsistent, the Suita Study showed that decreased HDL-C and increased non-HDL-C, but not increased TC, were associated with mild-to-moderate cognitive impairment. Management of serum cholesterol levels should be considered to prevent cognitive impairment.

The Relationship Between Dietary Patterns, Cognition, and Cardiometabolic Health in Healthy, Older Adults

BACKGROUND

Healthy dietary patterns can support the maintenance of cognition and brain health in older age and are negatively associated with cardiometabolic risk. Cardiometabolic risk factors are similarly important for cognition and may play an important role in linking diet to cognition.

AIM

This study aimed to explore the relationship between dietary patterns and cognition and to determine whether cardiometabolic health markers moderate these relationships in older adulthood.

DESIGN

A cross-sectional analysis of observational data from the baseline of the ACTIVate study.

PARTICIPANTS

The cohort included 426 cognitively normal adults aged 60-70 years.

METHODS

The Australian Eating Survey (AES) Food Frequency Questionnaire was used to collect data on usual dietary intake, along with additional questions assessing intake of dietary oils. Principal component analysis (PCA) was applied to reduce the dimensionality of dietary data. Cardiometabolic risk was quantified using the metabolic syndrome severity score (MetSSS). Tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB) were used to derive composite scores on four cognitive domains: processing speed, executive function, short-term memory, and long-term memory.

RESULTS

Three dietary patterns were identified using PCA: a plant-dominant diet, a Western-style diet, and a meat-dominant diet. After controlling for age, sex, total years of education, energy intake, and moderate-to-vigorous physical activity (MVPA), there was a small, negative association between the meat-dominant diets and long-term memory. Subsequent moderation analysis indicated that MetSSS significantly moderated this relationship.

CONCLUSIONS

Findings highlight the link between diet, cardiometabolic health, and cognitive function in older, cognitively healthy adults. However, longitudinal studies are needed to confirm observations and evaluate the dynamics of diet, cardiometabolic health, and cognitive function over time.

Apolipoprotein B gene expression and regulation in relation to Alzheimer's disease pathophysiology

Apolipoprotein B (APOB), a receptor-binding protein present in cholesterol-rich lipoproteins, has been implicated in Alzheimer's disease (AD). High levels of APOB-containing low-density lipoproteins (LDL) are linked to the pathogenesis of both early-onset familial and late-onset sporadic AD. Rare coding mutations in the APOB gene are associated with familial AD, suggesting a role for APOB-bound lipoproteins in the central nervous system. This research explores APOB gene regulation across the AD spectrum using four cohorts: BRAINEAC (elderly control brains), DBCBB (controls, AD brains), ROSMAP (controls, MCI, AD brains), and ADNI (control, MCI, AD clinical subjects). APOB protein levels, measured via mass spectrometry and ELISA, positively correlated with AD pathology indices and cognition, while APOB mRNA levels showed negative correlations. Brain APOB protein levels are also correlated with cortical Aβ levels. A common coding variant in the APOB gene locus affected its expression but didn't impact AD risk or brain cholesterol concentrations, except for 24-S-hydroxycholesterol. Polymorphisms in the CYP27A1 gene, notably rs4674344, were associated with APOB protein levels. A negative correlation was observed between brain APOB gene expression and AD biomarker levels. CSF APOB correlated with Tau pathology in presymptomatic subjects, while cortical APOB was strongly associated with cortical Aβ deposition in late-stage AD. The study discusses the potential link between blood-brain barrier dysfunction and AD symptoms in relation to APOB neurobiology. Overall, APOB's involvement in lipoprotein metabolism appears to influence AD pathology across different stages of the disease.

Lipids, lipoproteins, and apolipoproteins: Associations with cognition and dementia

Due to increasing lifespan and aging populations globally there has been a steep rise in late-life dementia, which is now the second most common cause of death in high-income countries. In general, dementia can be divided into two major groups: Alzheimer's disease (AD) and vascular-related dementia (VD). AD is pathologically characterised by senile plaques containing amyloid-β and neurofibrillary tangles composed of hyperphosphorylated tau, whereas VD is dominated by vascular pathology such as cerebral small vessel disease, major strokes, and white matter lesions. Recently, the importance of vascular components in AD is increasingly recognized and it is estimated that up to 45 % of all dementia cases can be prevented by preventing or treating midlife cardiovascular risk factors such as physical inactivity, diabetes, and hypertension. Even though the brain contains approximately 25 % of the total body cholesterol pool, and several genetic variants related to the lipid metabolism have been identified in genome-wide associations studies of AD, the role of lipids, lipoproteins, and apolipoproteins in dementia risk is less well-known. In this review, we go through the current literature on lipids, lipoproteins, and apolipoproteins and risk of dementia. We conclude that the evidence is primarily insufficient or conflicting, possibly due to nonoptimal study designs. The future calls for large, prospective studies of midlife measurements of lipids, lipoproteins, and apolipoproteins and one-sample, individual level data Mendelian randomization studies to overcome survival bias. However, the current literature suggests that it is safe to say that what is good for the heart is good for the brain.

Cationic Surface Charge Engineering of Recombinant Transthyretin Remarkably Increases the Inhibitory Potency Against Amyloid β-Protein Fibrillogenesis

The deposition of amyloid β-protein (Aβ) in the brain is the main pathogenesis of Alzheimer's disease (AD). The development of potent inhibitors against Aβ aggregation is one of the effective strategies to combat AD. Endogenous transthyretin (TTR) can inhibit Aβ fibrillization via hydrophobic interactions, but its weak inhibitory potency hinders its application in AD therapy. Here, different recombinant TTRs were designed by cationic surface charge engineering. Compared with TTR, all positively charged recombinant TTRs showed enhanced capability in inhibiting Aβ aggregation, especially the recombinant protein obtained by mutating the acidic amino acid in TTR to arginine (TTR-nR) exhibited excellent inhibitory effect. Among them, TTR-7R remarkably increased the inhibitory potency against Aβ, which could effectively inhibit Aβ40 fibrillization at a very low concentration (0.5 μM). In addition, TTR-7R increased cultured cell viability from 62% to 89%, scavenged amyloid plaques in AD nematodes, and prolonged nematode lifespan by 5 d at 2 μM. Thermodynamic studies demonstrated that TTR-7R, enriching in positive charges, presented hydrophobic interactions and enhanced electrostatic interactions with Aβ40, leading to a significantly enhanced inhibitory capacity of TTR-7R. The research provided insights into the development of efficient recombinant protein inhibitors for AD treatment.

Associations Between High-Density Lipoprotein Cholesterol Efflux and Brain Grey Matter Volume

Objective: High-density lipoprotein cholesterol efflux function may prevent brain amyloid beta deposition and neurodegeneration. However, the relevance of this finding has not been established in the diverse middle-aged population. Methods: We examined 1826 adults (47% Black adults) who participated in the Dallas Heart Study to determine associations between high-density lipoprotein (HDL) measures and brain structure and function. White matter hyperintensities (WMH) and whole-brain grey matter volume (GMV) were measured using brain MRI, and the Montreal Cognitive Assessment (MoCA) was used to measure neurocognitive function. HDL cholesterol efflux capacity (HDL-CEC) was assessed using fluorescence-labeled cholesterol efflux from J774 macrophages, and HDL particle size measures were assessed using nuclear magnetic resonance (NMR) spectroscopy (LipoScience). Multivariable linear regressions were performed to elucidate associations between HDL-CEC and brain and cognitive phenotypes after adjustment for traditional risk factors such as age, smoking status, time spent in daily physical activity, and education level. Results: Higher HDL-CEC and small HDL particle (HDL-P) concentration were positively associated with higher GMV normalized to total cranial volume (TCV) (GMV/TCV) after adjustment for relevant risk factors (β = 0.078 [95% CI: 0.029, 0.126], p = 0.002, and β = 0.063 [95% CI: 0.014, 0.111], p = 0.012, respectively). Conversely, there were no associations between HDL measures and WMH or MoCA (all p > 0.05). Associations of HDL-CEC and small HDL-P with GMV/TCV were not modified by ApoE-ε4 status or race/ethnicity. Interpretation: Higher HDL cholesterol efflux and higher plasma concentration of small HDL-P were associated with higher GMV/TCV. Additional studies are needed to explore the potential neuroprotective functions of HDL.

Change of leisure activity participation and associations with cognitive frailty in older adults: A population-based longitudinal study

OBJECTIVES

To examine changes in leisure activity participation and their associations with cognitive frailty among older adults.

METHODS

The study utilized data from the Chinese Longitudinal Healthy Longevity Survey covering 2008-2018. Three distinct intervals represented short-term (2008-2011), medium-term (2008-2014) and long-term (2008-2018) changes in leisure activity participation, and the change patterns of levels of leisure activities based on the tertile were described. Restricted cubic splines (RCS) were used to determine the inflection point of the absolute value of leisure activity participation over two time points. Group-based trajectory modeling identified trajectories of leisure activity participation among participants from 2008 to 2018. Logistic regression analysis examined how changes in leisure activity participation impacted cognitive frailty.

RESULTS

Five patterns of change in leisure activity participation were identified, including the persistently low group, the declining (medium-low, high-low, high-medium) group, persistently medium, rising (low-medium, low-high, medium-high), and persistently high levels of activity. A lower risk of cognitive frailty was found among three groups of persistently medium, rising, and persistently high levels of activity across three distinct intervals and among the declining group over the short-term and long-term intervals but not in the medium-term interval than among the persistently low group, respectively. RCS analysis showed that the inflection point of the association between absolute changes in leisure activity and cognitive frailty was -2.11 (short-term), -0.9 (medium-term), and -3.94 (long-term). Leisure activity trajectories were categorized into persistently low, persistently moderate, and persistently high groups, and both the persistently moderate and persistently high groups exhibited a lower risk of cognitive frailty compared to the persistently low group.

CONCLUSION

Persistently moderate to high levels and increasing levels of leisure activities can reduce the risk of cognitive frailty in the short, medium, and long term, and even the declining in leisure activity participation less than the threshold could protect against cognitive frailty, particularly in the short and long term.

Enhancing cognitive performance and mitigating dyslipidemia: the impact of moderate aerobic training on sedentary older adults

BACKGROUND

The present study aimed to evaluate the effects of 24 weeks of moderate aerobic exercise on lipids and lipoprotein levels; Lipo (a) markers, and their association with cognitive performance in healthy older adults.

METHODS

A total of 150 healthy subjects (100 males and 50 females; age range: 65-95 years) were recruited for this study. Based on the LOTCA test score, subjects were classified into two groups: the control group (n = 50) and the cognitive impairment group (n = 100). Cognitive functioning, leisure-time physical activity (LTPA), lipid profile, total cholesterol, TG, HDL-c, LDL-C, and lipo(a) were assessed at baseline and post-24-week aerobic exercise interventions using LOTCA battery, pre-validated Global Physical Activity Questionnaire (GPAQ) version II, colorimetric, and immunoassay techniques, respectively.

RESULTS

Significant improvements in cognitive function and modulation in lipid profile and lipoprotein (a) markers were reported in all older subjects following 24 weeks of moderate exercise. LOTCA-7-sets scores significantly correlated with physical activity status and the regulation of lipids and Lipo (a) markers. Physically active persons showed higher cognitive performance along with a reduction in the levels of T-Cholest., TG, LDL-C, Lipo (a), and an increase in the levels of HDL-C and aerobic fitness VO2max compared with sedentary participants. Cognitive performance correlated positively with increased aerobic fitness, HDL-C, and negatively with T-Cholest., TG, LDL-C, and Lipo (a). However, a significant increase in the improvement of motor praxis, vasomotor organization, thinking operations, attention, and concentration were reported among older adults.

CONCLUSIONS

The study findings revealed that supervised moderate aerobic training for 24 weeks significantly enhances cognitive functions via mitigating older adults' lipid profiles and lipoprotein (a). Cognitive performance is positively correlated with aerobic fitness and HDL-C level and negatively with T-Cholest., TH, LDL-C, and Lipo (a).

Microglia contribute to cognitive decline in hypercholesterolemic LDLr-/- mice

Familial hypercholesterolemia (FH) is caused by mutations in the gene that encodes the low-density lipoprotein (LDL) receptor, which leads to an excessive increase in plasma LDL cholesterol levels. Previous studies have shown that FH is associated with gliosis, blood-brain barrier dysfunction, and memory impairment, but the mechanisms associated with these events are still not fully understood. Therefore, we aimed to investigate the role of microgliosis in the neurochemical and behavioral changes associated with FH using LDL receptor knockout (LDLr-/-) mice. We noticed that microgliosis was more severe in the hippocampus of middle-aged LDLr-/- mice, which was accompanied by microglial morphological changes and alterations in the immunocontent of synaptic protein markers. At three months of age, the LDLr-/- mice already showed increased microgliosis and decreased immunocontent of claudin-5 in the prefrontal cortex (PFC). Subsequently, 6-month-old male C57BL/6 wild-type and LDLr-/- mice were treated once daily for 30 days with minocycline (a pharmacological inhibitor of microglial cell reactivity) or vehicle (saline). Adult LDLr-/- mice displayed significant hippocampal memory impairment, which was ameliorated by minocycline treatment. Non-treated LDLr-/- mice showed increased microglial density in all hippocampal regions analyzed, a process that was not altered by minocycline treatment. Region-specific microglial morphological analysis revealed different effects of genotype or minocycline treatment on microglial morphology, depending on the hippocampal subregion analyzed. Moreover, 6-month-old LDLr-/- mice exhibited a slight but not significant increase in IBA-1 immunoreactivity in the PFC, which was reduced by minocycline treatment without altering microglial morphology. Minocycline treatment also reduced the presence of microglia within the perivascular area in both the PFC and hippocampus of LDLr-/- mice. However, no significant effects of either genotype or minocycline treatment were observed regarding the phagocytic activity of microglia in the PFC and hippocampus. Our results demonstrate that hippocampal microgliosis, microglial morphological changes, and the presence of these glial cells in the perivascular area, but not increased microglial phagocytic activity, are associated with cognitive deficits in a mouse model of FH.

Cholesterol profiling reveals 7β-hydroxycholesterol as a pathologically relevant peripheral biomarker of Alzheimer's disease

AIM

Cholesterol homeostasis is associated with Alzheimer's disease (AD). Despite the multitude of cholesterol metabolites, little is known about which metabolites are directly involved in AD pathogenesis and can serve as its potential biomarkers.

METHODS

To identify "hit" metabolites, steroid profiling was conducted in mice with different age, diet, and genotype and also in humans with normal cognition, mild cognitive impairment, and AD using gas chromatography-mass spectrometry. Then, using one of the "hit" molecules (7β-hydroxycholesterol; OHC), molecular and histopathological experiment and behavioral testing were conducted in normal mice following its intracranial stereotaxic injection to see whether this molecule drives AD pathogenesis and causes cognitive impairment.

RESULTS

The serum levels of several metabolites, including 7β-OHC, were increased by aging in the 3xTg-AD unlike normal mice. Consistently, the levels of 7β-OHC were increased in the hairs of patients with AD and were correlated with clinical severity. We found that 7β-OHC directly affects AD-related pathophysiology; intrahippocampal injection of 7β-OHC induced astrocyte and microglial cell activation, increased the levels of pro-inflammatory cytokines (TNF-alpha, IL-1β, IL-6), and enhanced amyloidogenic pathway. Mice treated with 7β-OHC also exhibited deficits in memory and frontal/executive functions assessed by object recognition and 5-choice serial reaction time task, respectively.

CONCLUSIONS

Our results suggest that 7β-OHC could serve as a convenient, peripheral biomarker of AD. As directly involved in AD pathogenesis, 7β-OHC assay may help actualize personalized medicine in a way to identify an at-risk subgroup as a candidate population for statin-based AD treatment.

Association between Age at Diagnosis of Hyperlipidemia and Subsequent Risk of Dementia

OBJECTIVES

The relationship between age at diagnosis of hyperlipidemia and dementia remains unclear. We examined whether younger age at diagnosis of hyperlipidemia is associated with higher risk of subsequent dementia.

DESIGN

A longitudinal population-based study with a median follow-up of 12.8 years.

SETTING AND PARTICIPANTS

We analyzed data on a sample of 489,642 participants in the United Kingdom.

METHODS

This study was based on the UK Biobank. Information on hyperlipidemia and dementia diagnoses was collected at baseline (2006-2010) and follow-up [median = 12.8 years, interquartile range (IQR): 12.1-13.6 years]. Propensity score matching method and Cox proportional hazards models were used to assess the association between age at diagnosis of hyperlipidemia and dementia.

RESULTS

Among 489,642 participants (mean age: 56.9 ± 8.1 years; female: 54.7%), 114,112 (23.3%) were diagnosed with hyperlipidemia. Younger age at diagnosis of hyperlipidemia (per 10-year decrease) was significantly associated with higher risks of all-cause dementia [hazard ratio (HR), 1.12; 95% CI, 1.07-1.18; P < .001], Alzheimer's disease (AD) (HR, 1.22; 95% CI, 1.14-1.31; P < .001), and vascular dementia (VD) (HR, 1.16; 95% CI, 1.05-1.27; P < .001). After propensity score matching, patients with hyperlipidemia diagnosed before 50 years had the highest HR for all-cause dementia (HR, 1.46; 95% CI, 1.15-1.86; P = .002), followed by patients diagnosed between 50 and 69 years (HR, 1.21; 95% CI, 1.12-1.31; P < .001) and then patients diagnosed aged 70 years and older (HR, 0.94; 95% CI, 0.84-1.06; P = .302). Similar results were observed for AD and VD.

CONCLUSIONS AND IMPLICATIONS

A dose-response relationship between age at hyperlipidemia diagnosis and risk of dementia was found in the longitudinal cohort study, with younger age at diagnosis of hyperlipidemia being associated with higher subsequent risk.

The circadian syndrome is a predictor for cognition impairment in middle-aged adults: Comparison with the metabolic syndrome

AIMS

Circadian syndrome (CircS) is considered a better predictor for cardiovascular disease than the metabolic syndrome (MetS). We aim to examine the associations between CircS and MetS with cognition in Chinese adults.

METHOD

We used the data of 8546 Chinese adults aged ≥40 years from the 2011 China Health and Retirement Longitudinal Study. MetS was defined using harmonised criteria. CircS included the components of MetS plus short sleep and depression. The cut-off for CircS was set as ≥4. Global cognitive function was assessed during the face-to-face interview.

RESULTS

CircS and MetS had opposite associations with the global cognition score and self-reported poor memory. Compared with individuals without the CircS and MetS, the regression coefficients (95%CI) for global cognition score were -1.02 (-1.71 to -0.34) for CircS alone and 0.52 (0.09 to 0.96) for MetS alone in men; -1.36 (-2.00 to -0.72) for CircS alone and 0.60 (0.15 to 1.06) for MetS alone in women. Having CircS alone was 2.53 times more likely to report poor memory in men (95%CI 1.80-3.55) and 2.08 times more likely in women (95%CI 1.54-2.81). In contrast, having MetS alone was less likely to report poor memory (OR 0.64 (0.49-0.84) in men and 0.65 (0.52-0.81) in women). People with CircS and MetS combined were more likely to have self-reported poor memory.

CONCLUSIONS

CircS is a strong and better predictor for cognition impairment than MetS in Chinese middle-aged adults. MetS without short sleep and depression is associated with better cognition.

Serum proteomics study on cognitive impairment after cardiac valve replacement surgery: a prospective observational study

Objective

The incidence of perioperative neurocognitive disorders (PND) is high, especially after cardiac surgeries, and the underlying mechanisms remain elusive. Here, we conducted a prospective observational study to observe serum proteomics differences in PND patients after cardiac valve replacement surgery.

Methods

Two hundred and twenty-six patients who underwent cardiac valve surgery were included. They were categorized based on scoring into non-PND group (group non-P) and PND group (group P'). The risk factors associated with PND were analyzed. These patients were further divided into group C and group P by propensity score matching (PSM) to investigate the serum proteome related to the PND by serum proteomics.

Results

The postoperative 6-week incidence of PND was 16.8%. Risk factors for PND include age, chronic illness, sufentanil dosage, and time of cardiopulmonary bypass (CPB). Proteomics identified 31 down-regulated proteins and six up-regulated proteins. Finally, GSTO1, IDH1, CAT, and PFN1 were found to be associated with PND.

Conclusion

The occurrence of PND can impact some oxidative stress proteins. This study provided data for future studies about PND to general anaesthesia and surgeries.

Drug Development for Alzheimer's and Parkinson's Disease: Where Do We Go Now?

Neurodegenerative diseases (NDs) are a set of progressive, chronic, and incurable diseases characterized by the gradual loss of neurons, culminating in the decline of cognitive and/or motor functions. Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common NDs and represent an enormous burden both in terms of human suffering and economic cost. The available therapies for AD and PD only provide symptomatic and palliative relief for a limited period and are unable to modify the diseases' progression. Over the last decades, research efforts have been focused on developing new pharmacological treatments for these NDs. However, to date, no breakthrough treatment has been discovered. Hence, the development of disease-modifying drugs able to halt or reverse the progression of NDs remains an unmet clinical need. This review summarizes the major hallmarks of AD and PD and the drugs available for pharmacological treatment. It also sheds light on potential directions that can be pursued to develop new, disease-modifying drugs to treat AD and PD, describing as representative examples some advances in the development of drug candidates targeting oxidative stress and adenosine A2A receptors.

Effects of Future Subjective Expectations on Cognitive Decline and Dementia among Middle-Aged and Older Adults

This study investigated the impact of subjective expectations of the future (e.g., income, life expectancy, and national policies) on the onset of dementia and mild cognitive impairment by sex and age in middle-aged and older adults. The Korean Longitudinal Study of Aging (KLoSA) data from 2008 to 2020, comprising 4116 people above 45 years, were used. A time-series analysis and multiple panel logistic regression were conducted to highlight subjective expectation trends and their effect on dementia and mild cognitive impairment, respectively. Low subjective expectations of the future negatively affected cognitive impairment (total: odds ratio [OR] = 1.02, 95% confidence interval [CI] = 1.01-1.03) and dementia (total: OR = 1.05, 95% CI = 1.03-1.06), and those of national policies were the biggest risk factors for cognitive impairment (total: OR = 1.17, 95% CI = 1.12-1.22) and dementia (total: OR = 1.10, 95% CI = 1.07-1.13). Individuals about to retire and with low expectations of workability were more likely to develop cognitive impairment (total: OR = 1.03, 95% CI = 1.02-1.06). Subjective expectations of economic downturn also caused cognitive impairment, especially in women (OR = 1.04, 95% CI = 1.01-1.07) and early stage older adults (OR = 1.06, 95% CI = 1.02-1.10). Policymakers must consider the impact of changes in national policies and living environments on cognitive impairment and dementia in older adults.

Structural neuroimaging changes associated with subjective cognitive decline from a clinical sample

BACKGROUND

Alzheimer's disease (AD) is characterized by progressive deterioration of cognitive functions. Some individuals with subjective cognitive decline (SCD) are in the early phase of the disease and subsequently progress through the AD continuum. Although neuroimaging biomarkers could be used for the accurate and early diagnosis of preclinical AD, the findings in SCD samples have been heterogeneous. This study established the morphological differences in brain magnetic resonance imaging (MRI) findings between individuals with SCD and those without cognitive impairment based on a clinical sample of patients defined according to SCD-Initiative recommendations. Moreover, we investigated baseline structural changes in the brains of participants who remained stable or progressed to mild cognitive impairment or dementia.

METHODS

This study included 309 participants with SCD and 43 healthy controls (HCs) with high-quality brain MRI at baseline. Among the 99 subjects in the SCD group who were followed clinically, 32 progressed (SCDp) and 67 remained stable (SCDnp). A voxel-wise statistical comparison of gray and white matter (WM) volume was performed between the HC and SCD groups and between the HC, SCDp, and SCDnp groups. XTRACT ATLAS was used to define the anatomical location of WM tract damage. Region-of-interest (ROI) analyses were performed to determine brain volumetric differences. White matter lesion (WML) burden was established in each group.

RESULTS

Voxel-based morphometry (VBM) analysis revealed that the SCD group exhibited gray matter atrophy in the middle frontal gyri, superior orbital gyri, superior frontal gyri, right rectal gyrus, whole occipital lobule, and both thalami and precunei. Meanwhile, ROI analysis revealed decreased volume in the left rectal gyrus, bilateral medial orbital gyri, middle frontal gyri, superior frontal gyri, calcarine fissure, and left thalamus. The SCDp group exhibited greater hippocampal atrophy (p < 0.001) than the SCDnp and HC groups on ROI analyses. On VBM analysis, however, the SCDp group exhibited increased hippocampal atrophy only when compared to the SCDnp group (p < 0.001). The SCD group demonstrated lower WM volume in the uncinate fasciculus, cingulum, inferior fronto-occipital fasciculus, anterior thalamic radiation, and callosum forceps than the HC group. However, no significant differences in WML number (p = 0.345) or volume (p = 0.156) were observed between the SCD and HC groups.

CONCLUSIONS

The SCD group showed brain atrophy mainly in the frontal and occipital lobes. However, only the SCDp group demonstrated atrophy in the medial temporal lobe at baseline. Structural damage in the brain regions was anatomically connected, which may contribute to early memory decline.

Effects of risk factors on the development and mortality of early- and late-onset dementia: an 11-year longitudinal nationwide population-based cohort study in South Korea

BACKGROUND

Early-onset dementia (EOD, onset age < 65) and late-onset dementia (LOD, onset age ≥ 65) exhibit distinct features. Understanding the risk factors for dementia development and mortality in EOD and LOD respectively is crucial for personalized care. While risk factors are known for LOD development and mortality, their impact on EOD remains unclear. We aimed to investigate how hypertension, diabetes mellitus, hyperlipidemia, atrial fibrillation, and osteoporosis influence the development and mortality of EOD and LOD, respectively.

METHODS

Using the Korean National Health Insurance Service (NHIS) database, we collected 546,709 dementia-free individuals and followed up for 11 years. In the two study groups, the Younger group (< 65 years old) and the Older group (≥ 65 years old), we applied Cox proportional hazard models to assess risk factors for development of EOD and LOD, respectively. Then, we assessed risk factors for mortality among EOD and LOD.

RESULTS

Diabetes mellitus and osteoporosis increased the risk of EOD and LOD development. Hypertension increased the risk of EOD, while atrial fibrillation increased the risk of LOD. Conversely, hyperlipidemia exhibited a protective effect against LOD development. Additionally, diabetes mellitus increased mortality in EOD and LOD. Hypertension and atrial fibrillation increased mortality in LOD, while hyperlipidemia decreased mortality in EOD and LOD.

CONCLUSIONS

Risk factors influencing dementia development and mortality differed in EOD and LOD. Targeted public health interventions addressing age-related risk factors may reduce dementia incidence and mortality.

Vascular risk burden is a key player in the early progression of Alzheimer's disease

Understanding whether vascular risk factors (VRFs) synergistically potentiate Alzheimer's disease (AD) progression is important in the context of emerging treatments for preclinical AD. In a group of 503 cognitively unimpaired individuals, we tested whether VRF burden interacts with AD pathophysiology to accelerate neurodegeneration and cognitive decline. Baseline VRF burden was calculated considering medical data and AD pathophysiology was assessed based on cerebrospinal fluid (CSF) amyloid-β1-42 (Aβ1-42) and tau phosphorylated at threonine 181 (p-tau181). Neurodegeneration was assessed with plasma neurofilament light (NfL) and global cognition with the modified version of the Preclinical Alzheimer's Cognitive Composite. The mean (SD) age of participants was 72.9 (6.1) years, and 220 (43.7%) were men. Linear mixed-effects models revealed that an elevated VRF burden synergistically interacted with AD pathophysiology to drive longitudinal plasma NfL increase and cognitive decline. Additionally, VRF burden was not associated with CSF Aβ1-42 or p-tau181 changes over time. Our results suggest that VRF burden and AD pathophysiology are independent processes; however, they synergistically lead to neurodegeneration and cognitive deterioration. In preclinical stages, the combination of therapies targeting VRFs and AD pathophysiology might potentiate treatment outcomes.

Effects of cognitive reserve on cognitive frailty among older adults: A population-based prospective cohort study

AIM

We investigated the effect of lifespan cognitive reserve and its components on cognitive frailty among older adults.

METHODS

A total of 4922 participants aged ≥65 years were recruited in 2008 and were followed up in 2011 from the Chinese Longitudinal Healthy Longevity Survey. Cognitive frailty was determined through the simultaneous presence of physical frailty (pre-frailty or frailty) and mild cognitive impairment, excluding concurrent dementia. The assessment of physical frailty and mild cognitive impairment was based on the Fatigue, Resistence, Ambulation, Illness, Loss of weight (FRAIL) (Fatigue, Resistence, Ambulation, Illness, Loss) and Mini-Mental State Examination scale, respectively. The lifespan cognitive reserve consisted of education attainment, occupational complexity and later-life leisure activities. We used logistic regression models to estimate the risk of cognitive frailty associated with the lifespan cognitive reserve and its components.

RESULTS

A higher level of lifespan cognitive reserve, higher educational attainment or leisure activities engagement, but not occupational complexity, were associated with lower risk of incident cognitive frailty. Furthermore, cognitive, social and physical activities were associated with lower risk of incident cognitive frailty.

CONCLUSION

Cognitive reserve, particularly educational attainment and leisure activities, can protect from cognitive frailty. This implicates that individuals should accumulate cognitive reserve in their lifespan, and older adults should actively participate in leisure activities to prevent cognitive frailty. Geriatr Gerontol Int 2024; 24: 398-403.

Leveraging electronic health records and knowledge networks for Alzheimer's disease prediction and sex-specific biological insights

Identification of Alzheimer's disease (AD) onset risk can facilitate interventions before irreversible disease progression. We demonstrate that electronic health records from the University of California, San Francisco, followed by knowledge networks (for example, SPOKE) allow for (1) prediction of AD onset and (2) prioritization of biological hypotheses, and (3) contextualization of sex dimorphism. We trained random forest models and predicted AD onset on a cohort of 749 individuals with AD and 250,545 controls with a mean area under the receiver operating characteristic of 0.72 (7 years prior) to 0.81 (1 day prior). We further harnessed matched cohort models to identify conditions with predictive power before AD onset. Knowledge networks highlight shared genes between multiple top predictors and AD (for example, APOE, ACTB, IL6 and INS). Genetic colocalization analysis supports AD association with hyperlipidemia at the APOE locus, as well as a stronger female AD association with osteoporosis at a locus near MS4A6A. We therefore show how clinical data can be utilized for early AD prediction and identification of personalized biological hypotheses.

Lifestyle and factors of vascular and metabolic health and inflammation are associated with sensorineural-neurocognitive aging in older adults

This study's aim was to identify risk factors associated with sensorineural and neurocognitive function (brain aging) in older adults. In N = 1,478 Epidemiology of Hearing Loss Study participants (aged 64-100 years, 59% women), we conducted sensorineural and cognitive tests, which were combined into a summary measure using Principal Component Analysis (PCA). Participants with a PCA score <-1 standard deviation (SD) were considered to have brain aging. Incident brain aging was defined as PCA score <-1 SD at 5-year follow-up among participants who had a PCA score ≥-1 SD at baseline. Logistic regression and Poisson models were used to estimate associations between baseline risk factors of lifestyle, vascular and metabolic health, and inflammation and prevalent or incident brain aging, respectively. In an age-sex adjusted multivariable model, not consuming alcohol (odds ratio(OR) = 1.77, 95% confidence Interval (CI) = 1.18,2.66), higher interleukin-6 levels (OR = 1.30, 95% CI = 1.03,1.64), and depressive symptoms (OR = 2.44, 95% CI = 1.63,3.67) were associated with a higher odds of having brain aging, while higher education had protective effects (OR = 0.55, 95% CI = 0.33,0.94). A history of stroke, arterial stiffness, and obesity were associated with an increased risk of developing brain aging during the five years of follow-up. Lifestyle, vascular, metabolic and inflammatory factors were associated with brain aging in older adults, which adds to the evidence of shared pathways for sensorineural and neurocognitive declines in aging. Targeting these shared central processing etiological factors with interventions may lead to retention of better neurological function, benefiting multiple systems, i.e., hearing, smell, and cognition, ultimately helping older adults retain independence and higher quality of life longer.

Association between metabolic syndrome and risk of incident dementia in UK Biobank

INTRODUCTION

The association between metabolic syndrome (MetS) and incident dementia remains inconclusive.

METHODS

In 176,249 dementia-free UK Biobank participants aged ≥60 years at baseline, Cox proportional-hazards models were used to investigate the association between MetS and incident dementia. MetS was defined as the presence of ≥3 of the following: elevated waist circumference, triglycerides, blood pressure, blood glucose, and reduced high-density lipoprotein cholesterol.

RESULTS

Over 15 years of follow-up (median = 12.3), 5255 participants developed dementia. MetS was associated with an increased risk of incident dementia (hazard ratio [HR]: 1.12, 95% confidence interval [CI]: 1.06, 1.18). The association remained consistent when restricting to longer follow-up intervals: >5 to 10 years (HR: 1.17, 95% CI: 1.07, 1.27) and >10 years (HR: 1.22, 95% CI: 1.12, 1.32). Stronger associations were observed in those with ≥4 MetS components and in apolipoprotein-E (APOE)-ε4 non-carriers.

DISCUSSION

In this large population-based prospective cohort, MetS was associated with an increased risk of dementia.

HIGHLIGHTS

MetS was associated with a 12% increased risk of incident all-cause dementia. Associations remained similar after restricting the analysis to those with longer follow-up. The presence of four or five MetS components was significantly associated with dementia. Stronger associations were observed in those with a low genetic risk for dementia.

Association of Statin Use with Dementia Risk Among Older Adults in Japan: A Nested Case-Control Study Using the LIFE Study

Background

Previous studies have shown a possible association between statin use and a decreased risk of dementia, but the association has not been sufficiently established, especially in the super-aging society of Japan.

Objective

This study aimed to determine the association between statin use and the risk of dementia among Japanese participants aged> =65 years old.

Methods

Data from the Longevity Improvement and Fair Evidence (LIFE) Study were utilized, including medical and long-term care (LTC) claim data from 17 municipalities between April 2014 and December 2020. A nested case-control study was conducted with one case matched to five controls based on age, sex, municipality, and year of cohort entry. We used a conditional logistic regression model to calculate the odds ratios (ORs) and 95% confidence intervals (95% CIs).

Results

This study included 57,302 cases and 283,525 controls, with 59.7% of the participants being woman. After adjusting for potential confounders, statin use was associated with a lower risk of dementia (OR, 0.70; 95% CI: 0.68-0.73) and Alzheimer's disease (OR: 0.66; 95% CI: 0.63-0.69). Compared with non-users, the ORs of dementia were as follows: 1.42 (1.34-1.50) for 1-30 total standardized daily dose (TSDD), 0.91 (0.85-0.98) for 31-90 TSDD, 0.63 (0.58-0.69) for 91-180 TSDD, and 0.33 (0.31-0.36) for >180 TSDD in dose-analysis.

Conclusions

Statin use is associated with a reduced risk of dementia and Alzheimer's disease among older Japanese adults. A low cumulative statin dose is associated with an increased risk of dementia, whereas a high cumulative statin dose is a protective factor against dementia.

Beyond cardiovascular risk: Implications of Familial hypercholesterolemia on cognition and brain function

Familial hypercholesterolemia (FH) is a metabolic condition caused mainly by a mutation in the low-density lipoprotein (LDL) receptor gene (LDLR), which is highly prevalent in the population. Besides being an important causative factor of cardiovascular diseases, FH has been considered an early risk factor for Alzheimer's disease. Cognitive and emotional behavioral impairments in LDL receptor knockout (LDLr-/-) mice are associated with neuroinflammation, blood-brain barrier dysfunction, impaired neurogenesis, brain oxidative stress, and mitochondrial dysfunction. Notably, today, LDLr-/- mice, a widely used animal model for studying cardiovascular diseases and atherosclerosis, are also considered an interesting tool for studying dementia. Here, we reviewed the main findings in LDLr-/- mice regarding the relationship between FH and brain dysfunctions and dementia development.

Development and Concurrent Validity of the Short-Form CogDrisk Dementia Risk Assessment Tool

Evidence-based dementia risk assessment is required to inform individual and policy-level dementia risk reduction interventions. We developed the CogDrisk Short Form (CogDrisk-SF) to assess dementia risk factors, for situations where time and resources are limited. To evaluate concurrent validity with the original CogDrisk, we conducted an online survey using a repeated-measures, counterbalanced design. Community dwelling participants (n = 647, 50.1% were female, mean age 62.2 years, age range 40-89) completed the survey. The mean(sd) score for CogDrisk-SF and the CogDrisk was 9.7 (5.3) and 9.9 (5.5), respectively. The intraclass correlation between the risk score obtained from CogDrisk and CogDrisk-SF was 0.92. Fish intake, insomnia and depression had percentage agreements of 79%, 87% and 89% respectively. Other items had >95% agreement except for loneliness (94%), hypertension (94%), cholesterol (93%), atrial fibrillation (91%) and cognitive activity (90%). Very high agreement between the CogDrisk-SF and original CogDrisk shows that CogDrisk-SF is valid for use in research and clinical practice.

Hypertension & dementia: Pathophysiology & potential utility of antihypertensives in reducing disease burden

Dementia is a common cause of disability and dependency among the elderly due to its progressive neurodegenerative nature. As there is currently no curative therapy, it is of major importance to identify new ways to reduce its prevalence. Hypertension is recognised as a modifiable risk factor for dementia, particularly for the two most common subtypes; vascular dementia (VaD) and Alzheimer's disease (AD). From the current literature, identified through a comprehensive literature search of PubMed and Cochrane Library, this review aims to establish the stage in adulthood when hypertension becomes a risk for cognitive decline and dementia, and whether antihypertensive treatment is effective as a preventative therapy. Observational studies generally found hypertension in mid-life (age 45-64) to be correlated with an increased risk of cognitive decline and dementia incidence, including both VaD and AD. Hypertension manifesting in late life (age ≥ 65) was demonstrated to be less of a risk, to the extent that incidences of high blood pressure (BP) in the very elderly (age ≥ 75) may even be related to reduced incidence of dementias. Despite the evidence linking hypertension to dementia, there were conflicting findings as to whether the use of antihypertensives was beneficial for its prevention and this conflicting evidence and inconsistent results could be due to the methodological differences between the reviewed observational and randomised controlled trials. Furthermore, dihydropyridine calcium channel blockers and potassium-sparing diuretics were proposed to have neuroprotective properties in addition to BP lowering. Overall, if antihypertensives are confirmed to be beneficial by larger-scale homogenous trials with longer follow-up durations, treatment of hypertension, particularly in mid-life, could be an effective strategy to considerably lower the prevalence of dementia. Furthermore, greater clarification of the neuroprotective properties that some antihypertensives possess will allow for better clinical practice guidance on the choice of antihypertensive class for both BP lowering and dementia prevention.

The Relation Between Arterial Hypertension and Cognitive Impairment: A Literature Review

The global increase in dementia cases, driven by improved life expectancy and reduced elderly mortality rates, presents a significant public health challenge. Dementia, characterized by a gradual and irreversible decline in cognitive abilities, affects individuals aged 65 and older, disrupting lives and straining healthcare systems. Hypertension significantly influences dementia development. Research consistently links midlife hypertension to cognitive decline, mild cognitive impairment (MCI), and dementia, but findings in older adults vary. While some studies suggest that late-life hypertension accelerates cognitive decline and dementia risk, others propose a protective effect. The impact of hypertension on cognition varies across age groups, spanning from childhood to late life. High blood pressure during midlife and earlier life stages consistently predicts poorer cognitive outcomes. Executive function, attention, and motor speed are the cognitive domains most affected by hypertension, particularly in subcortical diseases. Memory impairments in hypertension-related dementias are complex, often overlapping with other causes. Understanding the inconsistent findings in older adults regarding hypertension, cognitive decline, and dementia risk requires comprehensive exploration of methodological and biological factors. Addressing hypertension and its management may hold the key to reducing the risk of cognitive decline and dementia, especially in midlife and earlier life stages.

[Cognitive impairment in patients with arterial hypertension]

Arterial hypertension (AH) is a leading risk factor for cardiovascular diseases including cerebrovascular complications. Strokes and/or vascular cognitive impairment (VCI) are considered as a clinical sign of brain damage as a target organ in hypertension. To identify and assess the severity of VCI, patients with hypertension should undergo a neuropsychological assessment. Neuroimaging confirm the vascular origin of cognitive impairment. Patient management should include antihypertensive therapy along with neuroprotection. Among different neuroprotective therapy, ethylmethylhydroxypyridine succinate (mexidol) is one of medication with serious evidence of clinical efficacy.

Neurodegenerative Diseases: New Hopes and Perspectives

Alzheimer's disease, Parkinson's disease, Amyotrophic lateral sclerosis, Huntington's disease, and Friedrich ataxia are all incurable neurodegenerative diseases defined by the continuous progressive loss of distinct neuronal subtypes. Despite their rising prevalence among the world's ageing population, fewer advances have been made in the concurrent massive efforts to develop newer drugs. Recently, there has been a shift in research focus towards the discovery of new therapeutic agents for neurodegenerative diseases. In this review, we have summarized the recently developed therapies and their status in the management of neurodegenerative diseases.

The association between varicella zoster virus and dementia: a systematic review and meta-analysis of observational studies

PURPOSE

The relationship between varicella zoster virus (VZV) infection and the risk of dementia has not been previously studied specifically. Therefore, this study sought to determine the relationship between studying VZV infection and dementia occurring in the general population by conducting an extensive meta-analysis of published cases.

METHOD

A systematic literature search was conducted in seven online databases by October 31, 2022. Heterogeneity was tested by the I2 index. Pooled HR and 95% CI were used to estimate the effect of VZV infection on dementia. Sensitivity analyses and publication bias were also performed.

RESULT

Nine studies involving 3,326,673 subjects were included. VZV infection was associated with an increased risk of dementia (HR = 1.11, 95% CI: 1.02-1.21). The risk of dementia was reduced in those who received antiviral therapy compared to those who did not (HR = 0.84, 95% CI: 0.71-0.99). In addition, VZV infection was found to be associated with an increased risk of developing dementia in the pooled results of the moderate quality study (HR = 1.81,95% CI: 1.27-2.59), and this association persisted when subgroup analyses were performed based on region (Asia: HR = 1.18,95% CI: 1.04-1.33).

CONCLUSIONS

Our results suggest that VZV infection might increase the risk of developing dementia, but there is no clear mechanism about the true relationship, and since there is no effective treatment for dementia, and our results suggest that some populations can benefit from antiviral therapy, it is at least arguable that patients who develop VZV infection should be treated with appropriate antiviral medications.