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The relationships between mastication and cognitive function: A systematic review and meta-analysis.The Japanese Dental Science Review Dec 2023Masticatory function such as chewing is expected to modify human cognitive function, and/or the possibility of improving cognitive function is also predicted. This... (Review)
Review
Masticatory function such as chewing is expected to modify human cognitive function, and/or the possibility of improving cognitive function is also predicted. This systematic review investigated whether masticatory function affects cognitive function for older/young adults. Full articles written in English from January 2000 to April 2022 were collected using PubMed and Cochrane Library. Target outcomes were cognitive function test scores, cognitive processing speed (reaction time), and masticatory function. For each research question, two independent reviewers conducted the search and screening, data extraction, quality assessment, and risk of bias assessment. The reviewers resolved any disagreements by discussion. From 226 articles retrieved, 20 were included in this review. Older adults with lower scores on the cognitive function test had lower masticatory performance, lower chewing ability, chewing difficulty, and decreased number of teeth. An increased risk of cognitive impairment was found in older adults with masticatory dysfunction. For young adults, gum chewing significantly reduced the processing speed of cognitive tasks compared to no gum chewing. Although most of the evidence included had a low level of evidence and a high risk of bias because of the research designs, the results still suggest that mastication may be a factor in improving cognitive function.
PubMed: 38022390
DOI: 10.1016/j.jdsr.2023.10.001 -
PloS One 2023Bullous pemphigoid (BP) is a rare autoimmune skin condition that causes large fluid-filled blisters on the skin, especially in older adults. BP has been linked to... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Bullous pemphigoid (BP) is a rare autoimmune skin condition that causes large fluid-filled blisters on the skin, especially in older adults. BP has been linked to various diseases and medications, but its association with cognitive outcomes is unclear.
METHODS
We conducted a systematic review and meta-analysis of studies investigating the association between BP and cognitive outcomes, such as all-cause dementia, Alzheimer's disease, and vascular dementia in middle-aged and older adults. We searched PubMed, Embase, and Web of Science databases for relevant studies published up to March 2023. We included studies that reported odds ratios (ORs) or hazard ratios (HRs) with 95% confidence intervals (CIs) for the association between BP and cognitive outcomes. We pooled the ORs, or HRs using random-effects models and performed subgroup and sensitivity analyses to explore potential sources of heterogeneity.
RESULTS
The study selection process identified 13 studies for inclusion in the analysis, 11 studied arms of which used a case-control design and 7 studied arms of which used a cohort design. The studies were conducted primarily in Europe, with a few from Asia and the United States. The meta-analysis found that BP was associated with higher odds of all-cause dementia in middle-aged and older participants in both cohort studies(HR = 1.41,95% CI: 1.20-1.66, P = 0.000) and case-control (OR = 4.25, 95% CI, 2.73-6.61; P = 0.000). The study found no significant publication bias in the included studies. The meta-regression analyses identified some subgroups associated with significantly reported odds ratios in case-control association analysis, including Europe, BP diagnosed based on clinical, histology, immunofluorescence, and both adjustment status of NO and YES.
CONCLUSIONS
Our meta-analysis suggests that BP is associated with an increased risk of all-cause dementia in middle-aged and older adults. Further studies are needed to elucidate the underlying mechanisms and causal relationship between BP and cognitive outcomes.
Topics: Middle Aged; Humans; Aged; Pemphigoid, Bullous; Alzheimer Disease; Cohort Studies; Europe; Autoimmune Diseases; Cognition; Cognitive Dysfunction
PubMed: 38033098
DOI: 10.1371/journal.pone.0295135 -
Nutrients Oct 2023This systematic review aims to provide a comprehensive understanding of the current literature regarding gut microbiota composition in patients with Parkinson's disease... (Review)
Review
This systematic review aims to provide a comprehensive understanding of the current literature regarding gut microbiota composition in patients with Parkinson's disease (PD) and Alzheimer's disease (AD) compared to healthy controls. To identify the relevant studies, a thorough search of PubMed, Medline, and Embase was conducted following the PRISMA guidelines. Out of 5627 articles, 73 studies were assessed for full-text eligibility, which led to the inclusion of 42 studies (26 PD and 16 AD studies). The risk of bias assessment showed a medium risk in 32 studies (20 PD studies and 12 AD studies), a low risk in 9 studies (5 PD studies and 4 AD studies), and 1 PD study with a high risk. Among the PD studies, 22 out of 26 studies reported a different gut microbiota composition between the PD cases and the healthy controls, and 15 out of 16 AD studies reported differences in gut microbiota composition between the AD cases and the healthy controls. The PD and AD studies consistently identified the phyla Bacteroidetes, Firmicutes, and Proteobacteria as prevalent in the gut microbiota in both the healthy groups and the case groups. Microbial dysbiosis was specifically characterized in the PD studies by a high abundance of , , , and in the cases and a high abundance of , , , and in the controls. Similarly, Bacteroides and Acidobacteriota were abundant in the AD cases, and , Firmicutes, , and were abundant in the AD controls. The microbial signature assessment showed the association of several microbial taxa, including , , , , , and Verrucomicrobia with PD and , , and Actinobacteria with AD. The microbial diversity evaluations in the PD and AD studies indicated comparable alpha diversity in some groups and distinct gut microbiota composition in others, with consistent beta diversity differences between the cases and the controls across multiple studies. The bacterial signatures identified in this study that are associated with PD and AD may offer promising prospects for efficient management and treatment approaches.
Topics: Humans; Gastrointestinal Microbiome; Parkinson Disease; Alzheimer Disease; Feces; Neurodegenerative Diseases; Bacteria
PubMed: 37892440
DOI: 10.3390/nu15204365 -
Nutrients Aug 2023Neurodegenerative diseases (NDs) have posed significant challenges to public health, and it is crucial to understand their mechanisms in order to develop effective... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Neurodegenerative diseases (NDs) have posed significant challenges to public health, and it is crucial to understand their mechanisms in order to develop effective therapeutic strategies. Recent studies have highlighted the potential role of selenium in ND pathogenesis, as it plays a vital role in maintaining cellular homeostasis and preventing oxidative damage. However, a comprehensive analysis of the association between selenium and NDs is still lacking.
METHOD
Five public databases, namely PubMed, Web of Science, EMBASE, Cochrane and Clinical Trials, were searched in our research. Random model effects were chosen, and Higgins inconsistency analyses (), Cochrane's Q test and Tau2 were calculated to evaluate the heterogeneity.
RESULT
The association of selenium in ND patients with Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS) and Huntington's disease (HD) was studied. A statistically significant relationship was only found for AD patients (SMD = -0.41, 95% CI (-0.64, -0.17), < 0.001), especially for erythrocytes. However, no significant relationship was observed in the analysis of the other four diseases.
CONCLUSION
Generally, this meta-analysis indicated that AD patients are strongly associated with lower selenium concentrations compared with healthy people, which may provide a clinical reference in the future. However, more studies are urgently needed for further study and treatment of neurodegenerative diseases.
Topics: Humans; Selenium; Neurodegenerative Diseases; Alzheimer Disease; Amyotrophic Lateral Sclerosis; Databases, Factual
PubMed: 37686737
DOI: 10.3390/nu15173706 -
Journal of the American Heart... Dec 2023Cerebral small vessel disease (cSVD) is a major contributing factor to ischemic stroke and dementia. However, the vascular pathologies of cSVD remain inconclusive. The... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Cerebral small vessel disease (cSVD) is a major contributing factor to ischemic stroke and dementia. However, the vascular pathologies of cSVD remain inconclusive. The aim of this systematic review and meta-analysis was to characterize the associations between cSVD and cerebrovascular reactivity (CVR), cerebral autoregulation, and arterial stiffness (AS).
METHODS AND RESULTS
MEDLINE, Web of Science, and Embase were searched from inception to September 2023 for studies reporting CVR, cerebral autoregulation, or AS in relation to radiological markers of cSVD. Data were extracted in predefined tables, reviewed, and meta-analyses performed using inverse-variance random effects models to determine pooled odds ratios (ORs). A total of 1611 studies were identified; 142 were included in the systematic review, of which 60 had data available for meta-analyses. Systematic review revealed that CVR, cerebral autoregulation, and AS were consistently associated with cSVD (80.4%, 78.6%, and 85.4% of studies, respectively). Meta-analysis in 7 studies (536 participants, 32.9% women) revealed a borderline association between impaired CVR and cSVD (OR, 2.26 [95% CI, 0.99-5.14]; =0.05). In 37 studies (27 952 participants, 53.0% women) increased AS, per SD, was associated with cSVD (OR, 1.24 [95% CI, 1.15-1.33]; <0.01). Meta-regression adjusted for comorbidities accounted for one-third of the AS model variance (=29.4%, =0.02). Subgroup analysis of AS studies demonstrated an association with white matter hyperintensities (OR, 1.42 [95% CI, 1.18-1.70]; <0.01).
CONCLUSIONS
The collective findings of the present systematic review and meta-analyses suggest an association between cSVD and impaired CVR and elevated AS. However, longitudinal investigations into vascular stiffness and regulatory function as possible risk factors for cSVD remain warranted.
Topics: Humans; Female; Male; Vascular Stiffness; Cerebral Small Vessel Diseases; Risk Factors; Magnetic Resonance Imaging
PubMed: 37930079
DOI: 10.1161/JAHA.123.032616 -
Neuroscience and Biobehavioral Reviews Apr 2024Conflicting evidence exists on the relationship between diabetes mellitus (DM) and Alzheimer's disease (AD) biomarkers. Therefore, we conducted a random-effects... (Meta-Analysis)
Meta-Analysis
Conflicting evidence exists on the relationship between diabetes mellitus (DM) and Alzheimer's disease (AD) biomarkers. Therefore, we conducted a random-effects meta-analysis to evaluate the correlation of glucose metabolism measures (glycated hemoglobin, fasting blood glucose, insulin resistance indices) and DM status with AD biomarkers of amyloid-β and tau measured by positron emission tomography or cerebrospinal fluid. We selected 37 studies from PubMed and Embase, including 11,694 individuals. More impaired glucose metabolism and DM status were associated with higher tau biomarkers (r=0.11[0.03-0.18], p=0.008; I2=68%), but were not associated with amyloid-β biomarkers (r=-0.06[-0.13-0.01], p=0.08; I=81%). Meta-regression revealed that glucose metabolism and DM were specifically associated with tau biomarkers in population settings (p=0.001). Furthermore, more impaired glucose metabolism and DM status were associated with lower amyloid-β biomarkers in memory clinic settings (p=0.004), and in studies with a higher prevalence of dementia (p<0.001) or lower cognitive scores (p=0.04). These findings indicate that DM is associated with biomarkers of tau but not with amyloid-β. This knowledge is valuable for improving dementia and DM diagnostics and treatment.
Topics: Humans; Alzheimer Disease; Amyloid beta-Peptides; Biomarkers; Cognitive Dysfunction; Diabetes Mellitus; Glucose; Peptide Fragments; Positron-Emission Tomography; tau Proteins
PubMed: 38423195
DOI: 10.1016/j.neubiorev.2024.105604 -
Frontiers in Immunology 2023Neuropathic pain is caused by a neurological injury or disease and can have a significant impact on people's daily lives. Studies have shown that neuropathic pain is...
BACKGROUND
Neuropathic pain is caused by a neurological injury or disease and can have a significant impact on people's daily lives. Studies have shown that neuropathic pain is commonly associated with neurodegenerative diseases. In recent years, there has been a lot of literature on the relationship between neuropathic pain and neurodegenerative diseases. However, bibliometrics is rarely used in analyzing the general aspects of studies on neuropathic pain in neurodegenerative diseases.
METHODS
The bibliometric analysis software CiteSpace and VOSviewer were used to analyze the knowledge graph of 387 studies in the Science Citation Index Expanded of the Web of Science Core Collection Database.
RESULTS
We obtained 2,036 documents through the search, leaving 387 documents after culling. 387 documents were used for the data analysis. The data analysis showed that 330 papers related to neuropathic pain in neurodegenerative diseases were published from 2007-2022, accounting for 85.27% of all published literature. In terms of contributions to the scientific study of neuropathic pain, the United States is in the top tier, with the highest number of publications, citations, and H-indexes.
CONCLUSION
The findings in our study may provide researchers with useful information about research trends, frontiers, and cooperative institutions. Multiple sclerosis, Parkinson's disease, and Alzheimer's disease are the three most studied neurodegenerative diseases. Among the pathological basis of neurodegenerative diseases, microglia-regulated neuroinflammation is a hot research topic. Deep brain stimulation and gamma knife radiosurgery are two popular treatments.
Topics: Humans; Neurodegenerative Diseases; Neuralgia; Alzheimer Disease; Parkinson Disease; Bibliometrics
PubMed: 37503342
DOI: 10.3389/fimmu.2023.1182411 -
Neuropsychology Review Sep 2023The current diagnostic criteria for the behavioural variant of frontotemporal dementia (bvFTD) foresee a relative sparing of long-term memory. Although bvFTD patients... (Review)
Review
Genuine Memory Deficits as Assessed by the Free and Cued Selective Reminding Test (FCSRT) in the Behavioural Variant of Frontotemporal Dementia. A Systematic Review and Meta-analysis Study.
The current diagnostic criteria for the behavioural variant of frontotemporal dementia (bvFTD) foresee a relative sparing of long-term memory. Although bvFTD patients were thought to report secondary memory deficits associated with prefrontal dysfunctions, some studies indicated the presence of a "genuine memory deficit" related to mesial temporal lobe dysfunctions. Among various neuropsychological tests, the Free and Cue Selective Reminding Test (FCSRT) has been recommended to distinguish genuine from apparent amnesia. We conducted a systematic review and a random effect Bayesian meta-analysis to evaluate the nature and severity of memory deficit in bvFTD. Our objective was to determine whether the existing literature offers evidence of genuine or apparent amnesia in patients with bvFTD, as assessed via the FCSRT. On 06/19/2021, we conducted a search across four databases (PMC, Scopus, Web of Science, and PubMed). We included all studies that evaluated memory performance using the FCSRT in patients with bvFTD, as long as they also included either cognitively unimpaired participants or AD groups. We tested publication bias through the Funnel plot and Egger's test. To assess the quality of studies, we used the Newcastle-Ottawa quality assessment scale adapted for cross-sectional studies. We included 16 studies in the meta-analysis. The results showed that bvFTD patients perform better than AD patients (pooled effects between 0.95 and 1.14), as their memory performance stands between AD and control groups (pooled effects between - 2.19 and - 1.25). Moreover, patients with bvFTD present both genuine and secondary memory disorders. As a major limitation of this study, due to our adoption of a rigorous methodology and stringent inclusion criteria, we ended up with just 16 studies. Nonetheless, our robust findings can contribute to the ongoing discussion on international consensus criteria for bvFTD and the selection of appropriate neuropsychological tools to facilitate the differential diagnosis between AD and bvFTD.
PubMed: 37736861
DOI: 10.1007/s11065-023-09613-3 -
Frontiers in Neurology 2023People with Alzheimer's disease (AD) have difficulties in performing activities of daily living (ADLs) as the disease progresses, commonly experience neuropsychiatric... (Review)
Review
Exploring the relationship between patient-relevant outcomes and Alzheimer's disease progression assessed using the clinical dementia rating scale: a systematic literature review.
BACKGROUND
People with Alzheimer's disease (AD) have difficulties in performing activities of daily living (ADLs) as the disease progresses, commonly experience neuropsychiatric symptoms (NPS), and often have comorbidities such as cardiovascular disease. These factors all contribute to a requirement for care and considerable healthcare costs in AD. The Clinical Dementia Rating (CDR) scale is a widely used measure of dementia staging, but the correlations between scores on this scale and patient-/care partner-relevant outcomes have not been characterized fully. We conducted a systematic literature review to address this evidence gap.
METHODS
Embase, MEDLINE, and the Cochrane Library were searched September 13, 2022, to identify published studies (no restriction by date or country) in populations with mild cognitive impairment due to AD or AD dementia. Studies of interest reported data on the relationships between CDR Global or CDR-Sum of Boxes (CDR-SB) scores and outcomes including NPS, comorbidities, ADLs, nursing home placement, healthcare costs, and resource use.
RESULTS
Overall, 58 studies met the inclusion criteria (42 focusing on comorbidities, 14 on ADLs or dependence, five on nursing home placement, and six on economic outcomes). CDR/CDR-SB scores were correlated with the frequency of multiple NPS and with total scores on the Neuropsychiatric Inventory. For cardiovascular comorbidities, no single risk factor was consistently linked to AD progression. Increasing CDR/CDR-SB scores were correlated with decline in multiple different measures of ADLs and were also associated with nursing home placement and increasing costs of care.
CONCLUSION
NPS, ADLs, and costs of care are clearly linked to AD progression, as measured using CDR Global or CDR-SB scores, from the earliest stages of disease. This indicates that scores derived from the CDR are a meaningful way to describe the severity and burden of AD for patients and care partners across disease stages.
PubMed: 37669257
DOI: 10.3389/fneur.2023.1208802 -
Frontiers in Aging Neuroscience 2023Mild cognitive impairment (MCI) is a preclinical and transitional stage between healthy ageing and dementia. The purpose of our study was to investigate the recent...
OBJECTIVE
Mild cognitive impairment (MCI) is a preclinical and transitional stage between healthy ageing and dementia. The purpose of our study was to investigate the recent pooled global prevalence of MCI.
METHODS
This meta-analysis was in line with the recommendations of Cochrane's Handbook and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020. We conducted a comprehensive search using the PubMed, Embase, Web of Science, CNKI, WFD, VIP, and CBM from their inception to March 1, 2023. Quality assessment was guided by the Agency for Healthcare Research and Quality (AHRQ) methodology checklist. The pooled global prevalence of MCI was synthesized using meta-analysis via random effect model. Subgroup analyses were performed to examine considered factors potentially associated with MCI prevalence.
RESULTS
We identified 233 studies involving 676,974 individuals aged above 50 years. All the studies rated as moderated-to-high quality. The overall prevalence of MCI was 19.7% [95% confidence interval (95% CI): 18.3-21.1%]. Subgroup analyses revealed that the global prevalence of MCI increased over time, with a significant rise [32.1% (95% CI: 22.6-41.6%)] after 2019. Additionally, MCI prevalence in hospitals [34.0% (95% CI: 22.2-45.7%)] was higher than in nursing homes [22.6% (95% CI: 15.5-29.8%)] and communities [17.9% (95% CI: 16.6-19.2%)], particularly after the epidemic of coronavirus disease 2019 (COVID-19).
CONCLUSION
The global prevalence of MCI was 19.7% and mainly correlated with beginning year of survey and sample source. The MCI prevalence increased largely in hospitals after 2019 may be related to the outbreak of COVID-19. Further attention to MCI is necessary in the future to inform allocation of health resources for at-risk populations.
PubMed: 37965493
DOI: 10.3389/fnagi.2023.1227112