scholarly journals Combined Effects of Aerobic Exercise and Diet on Lipids and Lipoproteins in Overweight and Obese Adults: A Meta-Analysis

2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
George A. Kelley ◽  
Kristi S. Kelley ◽  
Susan Roberts ◽  
William Haskell
Keyword(s):  
Aerobic Exercise ◽  
Random Effects ◽  
Effect Size ◽  
Meta Analysis ◽  
Combined Effects ◽  
Obese Adults ◽  
Men And Women ◽  
Random Effects Models ◽  
Multiple Groups ◽  
Lipids And Lipoproteins

This study used the aggregate data meta-analytic approach to determine the combined effects of aerobic exercise and diet on lipids and lipoproteins in overweight and obese adults. Twelve studies representing 859 men and women (443 intervention, 416 control) were included. Using random-effects models, statistically significant, intervention minus control reductions were found for TC (−12.8 mg/dL, 95% CI, −19.9 to −5.7), TC : HDL-C (−0.5 mg/dL, 95% CI, −0.8 to −0.1), LDL-C (−6.8 mg/dL, 95% CI, −11.8 to −1.8), and TG (−13.1 mg/dL, 95% CI, −21.2 to −5.0) but not HDL-C (−0.4 mg/dL, 95% CI, −2.3 to 1.6). Results remained robust when adjusted for publication bias, deleting each study from the model once, and collapsing results for multiple groups from the same study into one effect size. These findings suggest that concurrent aerobic exercise and diet improve TC, LDL-C, TC : HDL-C, and TG, but not HDL-C, in overweight and obese adults.

Detecting and correcting for publication bias in meta-analysis – A truncated normal distribution approach

2016 ◽  
Vol 27 (9) ◽  
pp. 2722-2741 ◽  
Author(s):  
Qiaohao Zhu ◽  
KC Carriere
Keyword(s):  
Normal Distribution ◽  
Publication Bias ◽  
Random Effects ◽  
Effect Size ◽  
Meta Analysis ◽  
Truncated Normal Distribution ◽  
Random Effects Models ◽  
Funnel Plot ◽  
Fixed And Random Effects ◽  
Truncated Normal

Publication bias can significantly limit the validity of meta-analysis when trying to draw conclusion about a research question from independent studies. Most research on detection and correction for publication bias in meta-analysis focus mainly on funnel plot-based methodologies or selection models. In this paper, we formulate publication bias as a truncated distribution problem, and propose new parametric solutions. We develop methodologies of estimating the underlying overall effect size and the severity of publication bias. We distinguish the two major situations, in which publication bias may be induced by: (1) small effect size or (2) large p-value. We consider both fixed and random effects models, and derive estimators for the overall mean and the truncation proportion. These estimators will be obtained using maximum likelihood estimation and method of moments under fixed- and random-effects models, respectively. We carried out extensive simulation studies to evaluate the performance of our methodology, and to compare with the non-parametric Trim and Fill method based on funnel plot. We find that our methods based on truncated normal distribution perform consistently well, both in detecting and correcting publication bias under various situations.

scholarly journals Improving the accuracy of likelihood-based inference in meta-analysis and meta-regression

Biometrika ◽  
2017 ◽  
Vol 104 (2) ◽  
pp. 489-496 ◽  
Author(s):  
I. Kosmidis ◽  
A. Guolo ◽  
C. Varin
Keyword(s):  
Random Effects ◽  
Effect Size ◽  
Variance Component ◽  
General Framework ◽  
Meta Analysis ◽  
Asymptotic Bias ◽  
Likelihood Estimator ◽  
Random Effects Models ◽  
The Mean ◽  
Meta Regression

Summary Random-effects models are frequently used to synthesize information from different studies in meta-analysis. While likelihood-based inference is attractive both in terms of limiting properties and of implementation, its application in random-effects meta-analysis may result in misleading conclusions, especially when the number of studies is small to moderate. The current paper shows how methodology that reduces the asymptotic bias of the maximum likelihood estimator of the variance component can also substantially improve inference about the mean effect size. The results are derived for the more general framework of random-effects meta-regression, which allows the mean effect size to vary with study-specific covariates.

scholarly journals Meta-Analysis of Sensorimotor Gating Deficits in Patients With Schizophrenia Evaluated by Prepulse Inhibition Test

2020 ◽  
Vol 46 (6) ◽  
pp. 1482-1497
Author(s):  
Rodrigo San-Martin ◽  
Leonardo Andrade Castro ◽  
Paulo Rossi Menezes ◽  
Francisco José Fraga ◽  
Priscyla Waleska Simões ◽  
...  
Keyword(s):  
Prepulse Inhibition ◽  
Random Effects ◽  
Effect Size ◽  
Meta Analysis ◽  
Sensorimotor Gating ◽  
Control Group ◽  
Random Effects Models ◽  
Meta Regression Analysis ◽  
High Level ◽  
Meta Analyses

Abstracts Prepulse inhibition (PPI) of startle is an operational measure of sensorimotor gating that is often impaired in patients with schizophrenia. Despite the large number of studies, there is considerable variation in PPI outcomes reported. We conducted a systematic review and meta-analysis investigating PPI impairment in patients with schizophrenia compared with healthy control subjects, and examined possible explanations for the variation in results between studies. Major databases were screened for observational studies comparing healthy subjects and patients with schizophrenia for the prepulse and pulse intervals of 60 and 120 ms as primary outcomes, ie, PPI-60 and PPI-120. Standardized mean difference (SMD) and 95% confidence intervals (CI) were extracted and pooled using random effects models. We then estimated the mean effect size of these measures with random effects meta-analyses and evaluated potential PPI heterogeneity moderators, using sensitivity analysis and meta-regressions. Sixty-seven primary studies were identified, with 3685 healthy and 4290 patients with schizophrenia. The schizophrenia group showed reduction in sensorimotor gating for both PPI-60 (SMD = −0.50, 95% CI = [−0.61, −0.39]) and PPI-120 (SMD = −0.44, 95% CI = [−0.54, −0.33]). The sensitivity and meta-regression analysis showed that sample size, gender proportion, imbalance for gender, source of control group, and study continent were sources of heterogeneity (P < .05) for both PPI-60 and PPI-120 outcomes. Our findings confirm a global sensorimotor gating deficit in schizophrenia patients, with overall moderate effect size for PPI-60 and PPI-120. Methodological consistency should decrease the high level of heterogeneity of PPI results between studies.

Aerobic Exercise And Diet Improve Selected Lipids And Lipoproteins In Overweight/obese Adults: A Meta-analysis

2011 ◽  
Vol 43 (Suppl 1) ◽  
pp. 278
Author(s):  
George A. Kelley ◽  
Kristi S. Kelley ◽  
Susan B. Roberts ◽  
William L. Haskell
Keyword(s):  
Aerobic Exercise ◽  
Meta Analysis ◽  
Obese Adults ◽  
Lipids And Lipoproteins

scholarly journals Dyslipidaemia and mortality in COVID-19 patients - a meta-analysis

QJM ◽  
2021 ◽  
Author(s):  
Marco Zuin ◽  
Gianluca Rigatelli ◽  
Claudio Bilato ◽  
Carlo Cervellati ◽  
Giovanni Zuliani ◽  
...  
Keyword(s):  
Random Effects ◽  
Mortality Risk ◽  
Meta Analysis ◽  
Random Effect ◽  
Final Analysis ◽  
Short Term ◽  
Random Effects Models ◽  
Pooled Prevalence ◽  
Statistical Heterogeneity ◽  
Trim And Fill

Abstract Objective The prevalence and prognostic implications of pre-existing dyslipidaemia in patients infected by the SARS-CoV-2 remain unclear. To perform a systematic review and meta-analysis of prevalence and mortality risk in COVID-19 patients with pre-existing dyslipidaemia. Methods Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed in abstracting data and assessing validity. We searched MEDLINE and Scopus to locate all the articles published up to January 31, 2021, reporting data on dyslipidaemia among COVID-19 survivors and non-survivors. The pooled prevalence of dyslipidaemia was calculated using a random effects model and presenting the related 95% confidence interval (CI), while the mortality risk was estimated using the Mantel-Haenszel random effects models with odds ratio (OR) and related 95% CI. Statistical heterogeneity was measured using the Higgins I2 statistic. Results Eighteen studies, enrolling 74.132 COVID-19 patients [mean age 70.6 years], met the inclusion criteria and were included in the final analysis. The pooled prevalence of dyslipidaemia was 17.5% of cases (95% CI: 12.3-24.3%, p < 0.0001), with high heterogeneity (I2=98.7%). Pre-existing dyslipidaemia was significantly associated with higher risk of short-term death (OR: 1.69, 95% CI: 1.19-2.41, p = 0.003), with high heterogeneity (I2=88.7%). Due to publication bias, according to the Trim-and-Fill method, the corrected random-effect ORs resulted 1.61, 95% CI 1.13-2.28, p < 0.0001 (one studies trimmed). Conclusions Dyslipidaemia represents a major comorbidity in about 18% of COVID-19 patients but it is associated with a 60% increase of short-term mortality risk.

scholarly journals Association of bisphenol A with puberty timing: a meta-analysis

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Hui Meng ◽  
Yunping Zhou ◽  
Yunxia Jiang
Keyword(s):  
Bisphenol A ◽  
Confidence Intervals ◽  
Random Effects ◽  
Strong Correlation ◽  
Fixed Effects ◽  
Meta Analysis ◽  
Random Effects Models ◽  
Study Heterogeneity ◽  
The Relationship ◽  
Prevalence Ratios

AbstractObjectivesThe results of existing studies on bisphenol A (BPA) and puberty timing did not reach a consensus. Thereby we performed this meta-analytic study to explore the association between BPA exposure in urine and puberty timing.MethodsMeta-analysis of the pooled odds ratios (OR), prevalence ratios (PR) or hazards ratios (HR) with 95% confidence intervals (CI) were calculated and estimated using fixed-effects or random-effects models based on between-study heterogeneity.ResultsA total of 10 studies involving 5621 subjects were finally included. The meta-analysis showed that BPA exposure was weakly associated with thelarche (PR: 0.96, 95% CI: 0.93–0.99), while no association was found between BPA exposure and menarche (HR: 0.99, 95% CI: 0.89–1.12; OR: 1.02, 95% CI: 0.73–1.43), and pubarche (OR: 1.00, 95% CI: 0.79–1.26; PR: 1.00, 95% CI: 0.95–1.05).ConclusionsThere was no strong correlation between BPA exposure and puberty timing. Further studies with large sample sizes are needed to verify the relationship between BPA and puberty timing.

EXPRESS: A meta-analysis of aspirin and subarachnoid haemorrhage in patients with intracranial aneurysms yields different results to the general population

2021 ◽  
pp. 174749302110048
Author(s):  
Frederick Ewbank ◽  
Jacqueline Birks ◽  
Diederik Bulters
Keyword(s):  
General Population ◽  
Subarachnoid Haemorrhage ◽  
Confidence Intervals ◽  
Random Effects ◽  
Intracranial Aneurysms ◽  
Meta Analysis ◽  
Risk Of Bias ◽  
Random Effects Models ◽  
Hazard Ratios ◽  
Unruptured Intracranial Aneurysms

Abstract Background Some studies have shown a protective association between aspirin use and subarachnoid haemorrhage (SAH). Other studies have found no relationship or the reverse. These studies differ in their study populations and definitions of SAH. Aims Our aim was to establish 1) if there is an association between aspirin and SAH, 2) how this differs between the general population and those with intracranial aneurysms. Summary of review Studies reporting aspirin use and the occurrence of SAH were included and grouped based on population (general population vs aneurysm population). Odds ratios, hazard ratios and confidence intervals were combined in random-effects models. 11 studies were included. Overall, there was an association between aspirin and SAH (OR 0.68 [0.48, 0.96]). However, populations were diverse and heterogeneity between studies high (p<0.00001), questioning the validity of combining these studies and justifying analysis by population. In the general population there was no difference in aspirin use between individuals with and without SAH (OR 1.15 [0.96, 1.38]). In patients with intracranial aneurysms, aspirin use was greater in patients without SAH (OR 0.37 [0.24, 0.58]), although these studies were at higher risk of bias. Conclusions There is an association between aspirin use and SAH in patients with intracranial aneurysms. This apparent protective relationship is not seen in the general population. Prospective randomised studies are required to further investigate the effect of aspirin on unruptured intracranial aneurysms.

scholarly journals Methods to calculate uncertainty in the estimated overall effect size from a random‐effects meta‐analysis

2018 ◽  
Vol 10 (1) ◽  
pp. 23-43 ◽  
Author(s):  
Areti Angeliki Veroniki ◽  
Dan Jackson ◽  
Ralf Bender ◽  
Oliver Kuss ◽  
Dean Langan ◽  
...  
Keyword(s):  
Random Effects ◽  
Effect Size ◽  
Meta Analysis

Abstract WP65: Low-Versus Standard-Dose Alteplase for AcuteIschemic Strokes Within 4.5 Hours: An updated Meta Analysis

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Huaguang Zheng ◽  
Xu Tong ◽  
Liping Liu ◽  
Zixiao Li ◽  
Xiaoling Liao ◽  
...  
Keyword(s):  
Cohort Studies ◽  
Random Effects ◽  
Standard Dose ◽  
Controlled Trial ◽  
Meta Analysis ◽  
Tissue Type ◽  
Random Effects Models ◽  
Dose Treatment ◽  
Randomized Controlled ◽  
Type Plasminogen Activator

Background and Purpose: We performed a meta-analysis to compare the outcomes between lower dose and standard dose intravenous tissue-type plasminogen activator (tPA) for acute ischemic stroke in randomized and non- randomized controlled trials. Methods: We searched PubMed for relevant studies and calculated pooled odds ratios (ORs) using random effects models.The primary endpoint was good functional outcome[modified Rankin Scale (mRS) of 0-1] at 3 month after stroke onset. Other major end points were all-cause mortality and symptomatic intracerebral haemorrhage (sICH). Results: From 2010 to 2016, 7 Cohort studies and 1 randomized controlled trial (ENCHANTED trial) were pooled in meta-analysis. The lower tPA strategy was likely to be less effective than the standard dose treatment (OR=0.87; 95% confidence interval [CI], 0.73-1.04, P=0.136; I 2 =47.9%, P=0.044 in random effects models and OR=0.88; 95% CI 0.88-0.98,P=0.016 ;I 2 =0.0%, P=0.693 in non- random effects models after 2 cohort studies were excluded due to heterogeneity). No difference was found for mortality at 90 days (OR=0.87; 95% CI 0.74-1.03, P=0.102 ;I 2 =0.0%, P=0.635 in non-random effects models)and sICH (OR=1.12; 95% CI 0.68-1.83,P=0.659; I 2 =57.6%, P=0.016 in random effects models and OR=1.23; 95% CI 0.92-1.65, P=0.168; I 2 =0.0%, P=0.547 in non-random effects models after 2 cohort studies were excluded due to heterogeneity ) between lower tPA group and standard dose . Conclusions: The low-dose alteplase strategy was less effective comparable to the standard-dose treatment .The safety was similar between the two strategies.

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