scholarly journals Adjusting for Variable Brain Coverage in Voxel-Based fMRI Meta-Analysis

2018 ◽  
Author(s):  
Jo Cutler ◽  
Joaquim Radua ◽  
Daniel Campbell-Meiklejohn
Keyword(s):  
Meta Analysis ◽  
Brain Regions ◽  
Random Effects Models ◽  
Z Scores ◽  
Novel Method ◽  
Meta Analyses ◽  
Type Ii Errors ◽  
Variable Subset ◽  
Unadjusted Analysis ◽  
Signal Dropout

Meta-analyses of fMRI studies are vital to establish consistent findings across the literature. However, fMRI data are susceptible to signal dropout (i.e. incomplete brain coverage), which varies across studies and brain regions. In other words, for some brain regions, only a variable subset of the studies included in an fMRI meta-analysis have data present. These missing data can mean activations in fMRI meta-analysis are underestimated (type II errors). Here we present SPM (MATLAB) code to run a novel method of adjusting random-effects models for meta-analytic averaging of a group of studies and mixed-effects models for comparison between two groups of studies. In two separate datasets, meta-analytic effect sizes and z-scores were larger in the adjusted, compared to the unadjusted analysis. Relevantly, these changes were in regions such as the ventromedial prefrontal cortex where coverage was lowest. Limitations of the method, including issues of how to threshold the adjusted maps are discussed. Code and demonstration data for the adjusted method are available at https://doi.org/10.25377/sussex.c.4223411.

scholarly journals To which extent are per-and poly-fluorinated substances associated to metabolic syndrome?

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Maryam Zare Jeddi ◽  
Rozita Soltanmohammadi ◽  
Giulia Barbieri ◽  
Aline S. C. Fabricio ◽  
Gisella Pitter ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
General Population ◽  
Meta Analysis ◽  
Small Body ◽  
Epidemiological Studies ◽  
Cross Sectional ◽  
Random Effects Models ◽  
Epidemiologic Evidence ◽  
Adults And Children ◽  
Meta Analyses

Abstract Exposure to per- and polyfluoroalkyl substances (PFAS), ubiquitous persistent environmental contaminants, has led to substantial global concern due to their potential environmental and human health effects. Several epidemiological studies have assessed the possible association between PFAS exposure and risk of metabolic syndrome (MetS), however, the results are ambiguous. The aim of this study was to assess the current human epidemiologic evidence on the association between exposure to PFAS and MetS. We performed a systematic search strategy using three electronic databases (PubMed, Scopus, and Web of Science) for relevant studies concerning the associations of PFAS with MetS and its clinical relevance from inception until January 2021. We undertook meta-analyses where there were five or more studies with exposure and outcomes assessments that were reasonably comparable. The pooled odd ratios (ORs) were calculated using random effects models and heterogeneity among studies was assessed by I2 index and Q test. A total of 12 cross-sectional studies (10 studies on the general population and two studies in the occupational settings) investigated the association between PFAS exposure and MetS. We pooled data from seven studies on the general population for perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) and five studies for perfluorohexanesulfonate (PFHxS) and perfluorononanoic acid (PFNA). Predominately, most studies reported no statistically significant association between concentrations of PFAS and MetS. In the meta-analysis, the overall measure of effect was not statistically significant, showing no evidence of an association between concentrations of PFOA, PFOS, PFNA, and PFHxS and the risk of MetS. Based on the results of the meta-analysis, current small body of evidence does not support association between PFAS and MetS. However, due to limited number of studies and substantial heterogeneity, results should be interpreted with caution. Further scrutinizing cohort studies are needed to evaluate the association between various and less well-known PFAS substances and their mixture with MetS and its components in both adults and children in different settings.

scholarly journals Leishmanicidal effects of resveratrol and its derivatives: a systematic review and meta-Analysis

2020 ◽  
Author(s):  
Nasrin Amiri Dashatan ◽  
Marzieh Ashrafmansouri ◽  
Mehdi Koushki ◽  
Nayebali Ahmadi
Keyword(s):  
Systematic Review ◽  
Publication Bias ◽  
Data Extraction ◽  
Meta Analysis ◽  
Sensitivity Analyses ◽  
Protective Effects ◽  
Random Effects Models ◽  
Important Health ◽  
Mean Differences ◽  
Meta Analyses

Abstract Background Leishmaniasis is one of the most important health problems worldwide. The evidence has suggested that resveratrol and its derivatives have anti-leishmanial effects; however, the results are inconsistent and inconclusive. The aim of this study was to assess the effect of resveratrol and its derivatives on the Leishmania viability through a systematic review and meta-analysis of available relevant studies. Methods The electronic databases PubMed, ScienceDirect, Embase, Web of Science and Scopus were queried between October 2000 and April 2020 using a comprehensive search strategy. The eligible articles selected and data extraction conducted by two reviewers. Mean differences of IC50 (concentration leading to reduction of 50% of Leishmania) for each outcome was calculated using random-effects models. Sensitivity analyses and prespecified subgroup were conducted to evaluate potential heterogeneity and the stability of the pooled results. Publication bias was evaluated using the Egger’s and Begg’s tests. We also followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines for this review. Results Ten studies were included in the meta-analysis. We observed that RSV and its derivatives had significant reducing effects on Leishmania viability in promastigote [24.02 µg/ml; (95% CI 17.1, 30.8); P < 0.05; I2 = 99.8%; P heterogeneity = 0.00] and amastigote [18.3 µg/ml; (95% CI 13.5, 23.2); P < 0.05; I2 = 99.6%; P heterogeneity = 0.00] stages of Leishmania. A significant publication bias was observed in the meta-analysis. Sensitivity analyses showed a similar effect size while reducing the heterogeneity. Subgroup analysis indicated that the pooled effects of leishmanicidal of resveratrol and its derivatives were affected by type of stilbenes and Leishmania species. Conclusions Our findings clearly suggest that the strategies for the treatment of leishmaniasis should be focused on natural products such as RSV and its derivatives. Further study is needed to identify the mechanisms mediating this protective effects of RSV and its derivatives in leishmaniasis.

scholarly journals A Meta-analysis of Functional Neuroimaging Studies of Self- and Other Judgments Reveals a Spatial Gradient for Mentalizing in Medial Prefrontal Cortex

2012 ◽  
Vol 24 (8) ◽  
pp. 1742-1752 ◽  
Author(s):  
Bryan T. Denny ◽  
Hedy Kober ◽  
Tor D. Wager ◽  
Kevin N. Ochsner
Keyword(s):  
Functional Organization ◽  
Functional Neuroimaging ◽  
Meta Analysis ◽  
Brain Regions ◽  
The Self ◽  
Spatial Gradient ◽  
Self And Other ◽  
Neuroimaging Data ◽  
Medial Pfc ◽  
Meta Analyses

The distinction between processes used to perceive and understand the self and others has received considerable attention in psychology and neuroscience. Brain findings highlight a role for various regions, in particular the medial PFC (mPFC), in supporting judgments about both the self and others. We performed a meta-analysis of 107 neuroimaging studies of self- and other-related judgments using multilevel kernel density analysis [Kober, H., & Wager, T. D. Meta-analyses of neuroimaging data. Wiley Interdisciplinary Reviews, 1, 293–300, 2010]. We sought to determine what brain regions are reliably involved in each judgment type and, in particular, what the spatial and functional organization of mPFC is with respect to them. Relative to nonmentalizing judgments, both self- and other judgments were associated with activity in mPFC, ranging from ventral to dorsal extents, as well as common activation of the left TPJ and posterior cingulate. A direct comparison between self- and other judgments revealed that ventral mPFC as well as left ventrolateral PFC and left insula were more frequently activated by self-related judgments, whereas dorsal mPFC, in addition to bilateral TPJ and cuneus, was more frequently activated by other-related judgments. Logistic regression analyses revealed that ventral and dorsal mPFC lay at opposite ends of a functional gradient: The z coordinates reported in individual studies predicted whether the study involved self- or other-related judgments, which were associated with increasingly ventral or dorsal portions of mPFC, respectively. These results argue for a distributed rather than localizationist account of mPFC organization and support an emerging view on the functional heterogeneity of mPFC.

Abstract WP196: Selective Serotonin Reuptake Inhibitors (SSRI) for Depression and Functional Recovery After Stroke: A Meta-Analysis

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Thirumalaivasan Dhasakeerthi ◽  
Muhammad Ishfaq ◽  
Balaji Krishnaiah ◽  
Andrei Alexandrov ◽  
Georgios Tsivgoulis
Keyword(s):  
Functional Recovery ◽  
Selective Serotonin Reuptake Inhibitors ◽  
Meta Analysis ◽  
Potential Effect ◽  
Control Group ◽  
Random Effects Models ◽  
Post Stroke Depression ◽  
Meta Analyses ◽  
And Function ◽  
Ssri Treatment

Background: Post-stroke depression is common and it impedes rehabilitation and function recovery after stroke, and numerous trials evaluated SSRI’s for depression prophylaxis. The objective of this study is to assess the use of SSRI for prevention of poststroke depression and the potential effect on functional recovery after stroke. Methods: We searched electronic databases up to July 2019 for randomized controlled trials of SSRI’s for patients with stroke versus placebo. We calculated pooled odds ratios and 95% CIs by using random-effects models. The primary end points were depression and good functional outcome (modified Rankin Scale score of 0-2) at 90 days post-randomization. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Results: Twelve randomized control trials assessing 4,887 patients have been included in the meta-analysis. SSRI treatment after stroke decreased the odds of depression compared to control group (OR = 0.48, 95% CI - 0.30 to 0.78, p=0.003). There was no heterogeneity between the trials (Cochran’s Q statistic 4.623, df 5; P = .337, I 2 =5.626%). The proportion of subjects who achieved mRS 0-2 at 90 days was similar between SSRI and control groups (OR= 3.471, 95% CI - 0.59 to 20.38, p=0.168). Conclusion: SSRI treatment for the stroke patients reduces the incidence of depression but it does not increase the odds of good functional recovery.

scholarly journals Adiposity and the risk of rheumatoid arthritis: a systematic review and meta-analysis of cohort studies

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tomoya Ohno ◽  
Dagfinn Aune ◽  
Alicia K. Heath
Keyword(s):  
Rheumatoid Arthritis ◽  
Systematic Review ◽  
Waist Circumference ◽  
Cohort Studies ◽  
Meta Analysis ◽  
Case Control Studies ◽  
Rheumatoid Arthritis Risk ◽  
Random Effects Models ◽  
Relative Risks ◽  
Meta Analyses

Abstract Several studies have investigated associations between overweight/obesity and risk of developing rheumatoid arthritis, however, the evidence is not entirely consistent, and previous meta-analyses mainly included case–control studies, which can be affected by various biases. We therefore conducted a systematic review and meta-analysis of cohort studies on adiposity and risk of rheumatoid arthritis. Relevant studies were identified by searching PubMed and Embase databases. Random effects models were used to estimate summary relative risks (RRs) and 95% confidence intervals (CIs) for rheumatoid arthritis in relation to different measures of adiposity. Thirteen cohort studies (10 publications) were included. The summary RR per 5 kg/m2 increase in body mass index (BMI) was 1.11 (95% CI 1.05–1.18, I2 = 50%), but the association was restricted to women (1.15, 95% CI 1.08–1.21, I2 = 17%) and not observed in men (0.89, 95% CI 0.73–1.09, I2 = 58%). The summary RR per 5 kg/m2 increment in BMI at age 18 years was 1.17 (95% CI 1.01–1.36, I2 = 26%, n = 3), and per 10 cm increase in waist circumference was 1.13 (95% CI 1.02–1.25, I2 = 44%, n = 2). Higher BMI in middle age, BMI at age 18 years, and waist circumference were associated with increased rheumatoid arthritis risk, suggesting adiposity could be targeted for primary prevention.

scholarly journals Comparison of different approaches to antibiotic restriction in food-producing animals: stratified results from a systematic review and meta-analysis

2019 ◽  
Vol 4 (4) ◽  
pp. e001710 ◽  
Author(s):  
Karen L Tang ◽  
Niamh P Caffrey ◽  
Diego B Nóbrega ◽  
Susan C Cork ◽  
Paul E Ronksley ◽  
...  
Keyword(s):  
Systematic Review ◽  
Antibiotic Resistance ◽  
Meta Analysis ◽  
Antibiotic Use ◽  
Growth Promoter ◽  
Antibiotic Resistant ◽  
Random Effects Models ◽  
Differential Effectiveness ◽  
Different Types ◽  
Meta Analyses

BackgroundWe have previously reported, in a systematic review of 181 studies, that restriction of antibiotic use in food-producing animals is associated with a reduction in antibiotic-resistant bacterial isolates. While informative, that report did not concretely specify whether different types of restriction are associated with differential effectiveness in reducing resistance. We undertook a sub-analysis of the systematic review to address this question.MethodsWe created a classification scheme of different approaches to antibiotic restriction: (1) complete restriction; (2) single antibiotic-class restriction; (3) single antibiotic restriction; (4) all non-therapeutic use restriction; (5) growth promoter and prophylaxis restriction; (6) growth promoter restriction and (7) other/undetermined. All studies in the original systematic review that were amenable to meta-analysis were included into this substudy and coded by intervention type. Meta-analyses were conducted using random effects models, stratified by intervention type.ResultsA total of 127 studies were included. The most frequently studied intervention type was complete restriction (n=51), followed by restriction of non-therapeutic (n=33) and growth promoter (n=19) indications. None examined growth promoter and prophylaxis restrictions together. Three and seven studies examined single antibiotic-class and single antibiotic restrictions, respectively; these two intervention types were not significantly associated with reductions in antibiotic resistance. Though complete restrictions were associated with a 15% reduction in antibiotic resistance, less prohibitive approaches also demonstrated reduction in antibiotic resistance of 9%–30%.ConclusionBroad interventions that restrict global antibiotic use appear to be more effective in reducing antibiotic resistance compared with restrictions that narrowly target one specific antibiotic or antibiotic class. Importantly, interventions that allow for therapeutic antibiotic use appear similarly effective compared with those that restrict all uses of antibiotics, suggesting that complete bans are not necessary. These findings directly inform the creation of specific policies to restrict antibiotic use in food-producing animals.

scholarly journals Altered central and blood glutathione in Alzheimer Disease and Mild Cognitive Impairment: a meta-analysis

2021 ◽  
Author(s):  
Jinghan J Chen ◽  
Mathura Thiyagarajah ◽  
Jianmeng Song ◽  
Clara Chen ◽  
Nathan Herrmann ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Alzheimer Disease ◽  
Publication Bias ◽  
Subgroup Analysis ◽  
Meta Analysis ◽  
Random Effects Models ◽  
Mean Differences ◽  
Meta Analyses

Abstract Background: Increasing evidence implicates oxidative stress (OS) in Alzheimer Disease (AD) and Mild Cognitive Impairment (MCI). Depletion of the brain antioxidant glutathione (GSH) may be important in OS-mediated neurodegeneration, though studies of post-mortem brain GSH changes in AD have been inconclusive. Recent in vivo measurements of brain and blood GSH may shed light on GSH changes earlier in the disease.Aim: To quantitatively review in vivo GSH in AD and MCI compared to healthy controls (HC) using meta-analyses. Method: Studies with in vivo brain or blood GSH levels in MCI or AD with a HC group were identified using Medline, PsychInfo, and Embase (1947-June 2020). Standardized mean differences (SMD) and 95% confidence intervals (CI) were calculated for outcomes using random effects models. Outcome measures included brain GSH (Meshcher-Garwood Point Resolved Spectroscopy (MEGA-PRESS) versus non-MEGA-PRESS), and blood GSH (intracellular versus extracellular) in AD and MCI. The Q statistic and Egger’s test were used to assess heterogeneity and risk of publication bias, respectively. Results: For brain GSH, 4 AD (AD=135, HC=223) and 4 MCI (MCI=213, HC=211) studies were included. For blood GSH, 26 AD (AD=1203, HC=1135) and 7 MCI (MCI=434, HC=408) studies were included. Brain GSH overall did not differ in AD or MCI compared to HC; however, the subgroup of studies using MEGA-PRESS reported lower brain GSH in AD (SMD [95%CI] -1.45 [-1.83, -1.06], p<0.001) and MCI (-1.15 [-1.71, -0.59], z=4.0, p<0.001). AD had lower intracellular and extracellular blood GSH overall (-1.10 [-1.58, -0.62], z=4.46, p<0.001). In a subgroup analysis, intracellular GSH was lower in MCI (-0.66 [-1.11, -0.21], p=0.025). Heterogeneity was observed throughout (I2 >85%) and not fully accounted by subgroup analysis. Egger’s test indicated risk of publication bias.Conclusion: Blood intracellular GSH decrease is seen in MCI, while both intra- and extracellular decreases were seen in AD. Brain GSH is decreased in AD and MCI in subgroup analysis. Potential bias and heterogeneity suggest the need for measurement standardization and additional studies to explore sources of heterogeneity.

scholarly journals Prognostic Role of Matrix Metalloproteinases in Cervical Cancer: A Meta-Analysis

2021 ◽  
Vol 28 ◽  
pp. 107327482110337
Author(s):  
Weiwei Chen ◽  
Shenjiao Huang ◽  
Kun Shi ◽  
Lisha Yi ◽  
Yaqiong Liu ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Matrix Metalloproteinases ◽  
Random Effects ◽  
Fixed Effects ◽  
Prognostic Value ◽  
Meta Analysis ◽  
Free Survival ◽  
Random Effects Models ◽  
Registration Number ◽  
Meta Analyses

Objective Studies have published the association between the expression of matrix metalloproteinases (MMPs) and the outcome of cervical cancer. However, the prognostic value in cervical cancer remains controversial. This meta-analysis was conducted to evaluate the prognostic functions of MMP expression in cervical cancer. Methods A comprehensive search of PubMed, Embase, and Web of Science databases was conducted to identify the eligible studies according to defined selection and excluding criteria and analyzed according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Fixed and random effects models were evaluated through the hazard ratios (HRs) and 95% confidence intervals (CIs) to estimate the overall survival (OS), recurrence-free survival (RFS), and progress-free survival (PFS). Results A total of 18 eligible studies including 1967 patients were analyzed for prognostic value. Totally 16 selected studies including 21 tests were relevant to the cervical cancer OS, 4 studies focused on RFS, and 1 study on PFS. The combined pooled HRs and 95% CIs of OS were calculated with random-effects models (HR = 1.64, 95% CI = 1.01–2.65, P = .000). In the subgroup analysis for OS, there was no heterogeneity in MMP-2 (I2 = .0%, P = .880), MMP-1 (I2 = .0%, P = .587), and MMP-14 (I2 = 28.3%, P = .248). In MMP-7 and MMP-9, the heterogeneities were obvious (I2 = 99.2% ( P = .000) and I2 = 77.9% ( P = .000), respectively). The pooled HRs and 95% CIs of RFS were calculated with fixed-effects models (HR = 2.22, 95% CI = 1.38–3.58, P = .001) and PFS (HR = 2.29, 95% CI = 1.14–4.58, P = .035). Conclusions The results indicated that MMP overexpression was associated with shorter OS and RFS in cervical cancer patients. It suggested that MMP overexpression might be a poor prognostic marker in cervical cancer. Research Registry Registration Number: reviewregistry 1159.

scholarly journals Prevalence and prognostic value of elevated troponins in patients hospitalised for coronavirus disease 2019: a systematic review and meta-analysis

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Bing-Cheng Zhao ◽  
Wei-Feng Liu ◽  
Shao-Hui Lei ◽  
Bo-Wei Zhou ◽  
Xiao Yang ◽  
...  
Keyword(s):  
Systematic Review ◽  
Prognostic Value ◽  
Meta Analysis ◽  
Multivariable Analysis ◽  
Significant Heterogeneity ◽  
Random Effects Models ◽  
Reference Limit ◽  
Risk Of Death ◽  
Upper Reference Limit ◽  
Meta Analyses

Abstract Background The clinical significance of cardiac troponin measurement in patients hospitalised for coronavirus disease 2019 (covid-19) is uncertain. We investigated the prevalence of elevated troponins in these patients and its prognostic value for predicting mortality. Methods Studies were identified by searching electronic databases and preprint servers. We included studies of hospitalised covid-19 patients that reported the frequency of troponin elevations above the upper reference limit and/or the association between troponins and mortality. Meta-analyses were performed using random-effects models. Results Fifty-one studies were included. Elevated troponins were found in 20.8% (95% confidence interval [CI] 16.8–25.0 %) of patients who received troponin test on hospital admission. Elevated troponins on admission were associated with a higher risk of subsequent death (risk ratio 2.68, 95% CI 2.08–3.46) after adjusting for confounders in multivariable analysis. The pooled sensitivity of elevated admission troponins for predicting death was 0.60 (95% CI 0.54–0.65), and the specificity was 0.83 (0.77–0.88). The post-test probability of death was about 42% for patients with elevated admission troponins and was about 9% for those with non-elevated troponins on admission. There was significant heterogeneity in the analyses, and many included studies were at risk of bias due to the lack of systematic troponin measurement and inadequate follow-up. Conclusion Elevated troponins were relatively common in patients hospitalised for covid-19. Troponin measurement on admission might help in risk stratification, especially in identifying patients at high risk of death when troponin levels are elevated. High-quality prospective studies are needed to validate these findings. Systematic review registration PROSPERO CRD42020176747

scholarly journals An fMRI Study Using a Combined Task of Interval Discrimination and Oddball Could Reveal Common Brain Circuits of Cognitive Change

2021 ◽  
Vol 12 ◽  
Author(s):  
María Sol Garcés ◽  
Irene Alústiza ◽  
Anton Albajes-Eizagirre ◽  
Javier Goena ◽  
Patricio Molero ◽  
...  
Keyword(s):  
Cognitive Processes ◽  
Healthy Subjects ◽  
Functional Neuroimaging ◽  
Meta Analysis ◽  
Brain Structures ◽  
Cognitive Change ◽  
Brain Regions ◽  
Task Type ◽  
Meta Analyses ◽  
The Brain

Recent functional neuroimaging studies suggest that the brain networks responsible for time processing are involved during other cognitive processes, leading to a hypothesis that time-related processing is needed to perform a range of tasks across various cognitive functions. To examine this hypothesis, we analyze whether, in healthy subjects, the brain structures activated or deactivated during performance of timing and oddball-detection type tasks coincide. To this end, we conducted two independent signed differential mapping (SDM) meta-analyses of functional magnetic resonance imaging (fMRI) studies assessing the cerebral generators of the responses elicited by tasks based on timing and oddball-detection paradigms. Finally, we undertook a multimodal meta-analysis to detect brain regions common to the findings of the two previous meta-analyses. We found that healthy subjects showed significant activation in cortical areas related to timing and salience networks. The patterns of activation and deactivation corresponding to each task type partially coincided. We hypothesize that there exists a time and change-detection network that serves as a common underlying resource used in a broad range of cognitive processes.

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