scholarly journals Abdominal Adiposity Distribution in Diabetic/Prediabetic and Nondiabetic Populations: A Meta-Analysis

2014 ◽  
Vol 2014 ◽  
pp. 1-20 ◽  
Author(s):  
Jane J. Lee ◽  
S. Natasha Beretvas ◽  
Jeanne H. Freeland-Graves
Keyword(s):  
Meta Analysis ◽  
Subcutaneous Fat ◽  
Assessment Method ◽  
Health Condition ◽  
Effect Sizes ◽  
Abdominal Adiposity ◽  
Fat Depots ◽  
Moderator Effects ◽  
Analysis Technique ◽  
Subcutaneous Adiposity

Excess fat in the abdomen can be classified generally as visceral and subcutaneous adiposity. Evidence suggests that visceral adiposity has greater implications for diabetes than other fat depots. The purpose of this study is to explore the disparities in the distribution of abdominal adiposity in diabetic/prediabetic and nondiabetic populations and to identify moderators that influence the pattern of central obesity via a meta-analysis technique. The Hedges’gwas used as a measure of effect size and 95% confidence interval was computed. A total of 41 relevant studies with 101 effect sizes were retrieved. Pooled effect sizes for visceral and subcutaneous adiposity were 0.69 and 0.42, respectively. Diabetic/prediabetic populations exhibited greater visceral and subcutaneous adiposity compared to nondiabetic populations (Z=10.35,P<0.05). Significant moderator effects of gender (Z=-2.90) and assessment method of abdominal adiposity (Z=-2.17) were found for visceral fat (P<0.05), but not for subcutaneous fat. Type of health condition influenced both visceral (Z=-5.10) and subcutaneous (Z=-7.09) abdominal adiposity volumes (P<0.05). Abdominal adiposity distributions were significantly altered in the diabetic/prediabetic population compared to the nondiabetic population. Gender, assessment method of abdominal adiposity, and type of health conditions (diabetic/prediabetics) were identified as crucial moderators that influence the degree of abdominal adiposity.

The Relationship between Physical Activity and Cognition in Children: A Meta-Analysis

2003 ◽  
Vol 15 (3) ◽  
pp. 243-256 ◽  
Author(s):  
Benjamin A. Sibley ◽  
Jennifer L. Etnier
Keyword(s):  
Physical Activity ◽  
Cognitive Assessment ◽  
Meta Analysis ◽  
Assessment Method ◽  
Effect Sizes ◽  
Inclusion Criteria ◽  
Moderator Variables ◽  
Method Effect ◽  
The Relationship ◽  
Significant Moderator

The purpose of this study was to quantitatively combine and examine the results of studies pertaining to physical activity and cognition in children. Studies meeting the inclusion criteria were coded based on design and descriptive characteristics, subject characteristics, activity characteristics, and cognitive assessment method. Effect sizes (ESs) were calculated for each study and an overall ES and average ESs relative to moderator variables were then calculated. ESs (n = 125) from 44 studies were included in the analysis. The overall ES was 0.32 (SD = 0.27), which was significantly different from zero. Significant moderator variables included publication status, subject age, and type of cognitive assessment. As a result of this statistical review of the literature, it is concluded that there is a significant positive relationship between physical activity and cognitive functioning in children.

Predicting behavioral intentions to prevent or mitigate COVID-19: A meta-analysis

2020 ◽  
Author(s):  
Ronald Fischer ◽  
Johannes Alfons Karl
Keyword(s):  
Social Norms ◽  
Behavioral Intentions ◽  
Behavioral Control ◽  
Meta Analysis ◽  
Effect Sizes ◽  
Perceived Behavioral Control ◽  
Negative Consequences ◽  
Moderator Effects ◽  
Societal Level ◽  
Strength Of Association

We examined the effectiveness of attitudes, social norms and perceived behavioral control on behavioral intentions and behaviors that prevent and mitigate COVID-19 infections and collateral negative consequences. We conducted a random-effects meta-analysis with 29 effect sizes from 19 studies involving data from 11 countries (N = 15,328). We found strongest effects for perceived behavioral control, but also moderately strong effects of social norms. This is practically important in a pandemic environment because social norms in other health contexts typically show negligible effects and advice based on non-pandemic contexts may be misguided. Examining moderator effects, we are the first to demonstrate that in contexts with strong endorsement of social norms, norm-behavior effects were strengthened. Focusing on societal level differences, both wealth and individualism increased the strength of association between perceived behavioral control and behavioral intentions. We discuss the practical and theoretical implications of the findings for behavior change and public health interventions.

scholarly journals Network meta-analysis: application and practice using R software

2019 ◽  
Vol 41 ◽  
pp. e2019013 ◽  
Author(s):  
Sung Ryul Shim ◽  
Seong-Jang Kim ◽  
Jonghoo Lee ◽  
Gerta Rücker
Keyword(s):  
Meta Analysis ◽  
Effect Sizes ◽  
Analysis Model ◽  
R Software ◽  
Data Synthesis ◽  
Theoretical Concepts ◽  
Moderator Effects ◽  
Analysis Application ◽  
R Packages ◽  
Meta Analyses

The objective of this study is to describe the general approaches to network meta-analysis that are available for quantitative data synthesis using R software. We conducted a network meta-analysis using two approaches: Bayesian and frequentist methods. The corresponding R packages were “gemtc” for the Bayesian approach and “netmeta” for the frequentist approach. In estimating a network meta-analysis model using a Bayesian framework, the “rjags” package is a common tool. “rjags” implements Markov chain Monte Carlo simulation with a graphical output. The estimated overall effect sizes, test for heterogeneity, moderator effects, and publication bias were reported using R software. The authors focus on two flexible models, Bayesian and frequentist, to determine overall effect sizes in network meta-analysis. This study focused on the practical methods of network meta-analysis rather than theoretical concepts, making the material easy to understand for Korean researchers who did not major in statistics. The authors hope that this study will help many Korean researchers to perform network meta-analyses and conduct related research more easily with R software.

Does Caffeine Added to Carbohydrate Provide Additional Ergogenic Benefit for Endurance?

2011 ◽  
Vol 21 (1) ◽  
pp. 71-84 ◽  
Author(s):  
Scott A. Conger ◽  
Gordon L. Warren ◽  
Michelle A. Hardy ◽  
Mindy L. Millard-Stafford
Keyword(s):  
Endurance Exercise ◽  
Human Subjects ◽  
Meta Analysis ◽  
Endurance Performance ◽  
Exercise Duration ◽  
Assessment Method ◽  
Effect Sizes ◽  
Performance Task ◽  
Condition Effect ◽  
Significant Performance

Context:Carbohydrate (CHO) and caffeine (CAF) both improve endurance performance.Purpose:To determine by systematic literature review coupled with meta-analysis whether CAF ingested with CHO (CHO+CAF) improves endurance performance more than CHO alone.Methods:Databases were searched using the keywords caffeine, endurance, exercise, carbohydrate, and performance. Criteria for inclusion were studies that used human subjects performing an endurance-exercise performance task and included both a CHO and CHO+CAF condition. Effect sizes (ESs) were calculated as the standardized mean difference.Results:Twenty-one studies met the criteria for analysis. ESs for individual studies ranged from –0.08 (trivial effect favoring CHO) to 1.01 (large effect favoring CHO+CAF). The overall ES equaled 0.26 (95% CI 0.15–0.38, p < .001), indicating that CHO+CAF provides a small but significant performance benefit over CHO. ES was not significantly (p > .05) related to CAF dose, exercise duration, or performance-assessment method. To determine whether ES of CHO+CAF vs. CHO was different than CAF compared with water (placebo), a subgroup meta-analysis compared 36 CAF vs. placebo studies against the 21 CHO+CAF vs. CHO studies. The overall ES for the former group of studies (ES = 0.51, 95% CI 0.40–0.61) was nearly 2-fold greater than in CHO+CAF vs. CHO studies (p = .006).Conclusions:CHO+CAF ingestion provides a significant but small effect to improve endurance performance compared with CHO alone. However, the magnitude of the performance benefit that CAF provides is less when added to CHO than when added to placebo.

Bullying and Suicidal Ideation and Behaviors: A Meta-Analysis

2018 ◽  
pp. 53-72
Author(s):  
Melissa K. Holt ◽  
Alana M. Vivolo-Kantor ◽  
Joshua R. Polanin ◽  
Kristin M. Holland ◽  
Sarah DeGue ◽  
...  
Keyword(s):  
Suicidal Ideation ◽  
Meta Analysis ◽  
Assessment Method ◽  
Effect Sizes ◽  
Significant Heterogeneity ◽  
Bullying Perpetration ◽  
Victim Status ◽  
And Behaviors ◽  
Meta Analyses ◽  
And Behavior

BACKGROUND AND OBJECTIVES Over the last decade there has been increased attention to the association between bullying involvement (as a victim, perpetrator, or bully-victim) and suicidal ideation/behaviors. We conducted a meta-analysis to estimate the association between bullying involvement and suicidal ideation and behaviors. METHODS We searched multiple online databases and reviewed reference sections of articles derived from searches to identify cross-sectional studies published through July 2013. Using search terms associated with bullying, suicide, and youth, 47 studies (38.3% from the United States, 61.7% in non-US samples) met inclusion criteria. Seven observers independently coded studies and met in pairs to reach consensus. RESULTS Six different meta-analyses were conducted by using 3 predictors (bullying victimization, bullying perpetration, and bully/victim status) and 2 outcomes (suicidal ideation and suicidal behaviors). A total of 280 effect sizes were extracted and multilevel, random effects meta-analyses were performed. Results indicated that each of the predictors were associated with risk for suicidal ideation and behavior (range, 2.12 [95% confidence interval (CI), 1.67–2.69] to 4.02 [95% CI, 2.39–6.76]). Significant heterogeneity remained across each analysis. The bullying perpetration and suicidal behavior effect sizes were moderated by the study’s country of origin; the bully/victim status and suicidal ideation results were moderated by bullying assessment method. CONCLUSIONS Findings demonstrated that involvement in bullying in any capacity is associated with suicidal ideation and behavior. Future research should address mental health implications of bullying involvement to prevent suicidal ideation/behavior.

Mental Imagery Meta-analysis

2017 ◽  
Author(s):  
Dominic Conroy ◽  
Martin S Hagger
Keyword(s):  
Mental Imagery ◽  
Meta Analysis ◽  
Health Behaviours ◽  
Effect Sizes ◽  
Data Sets ◽  
Independent Data ◽  
Physiological Measures ◽  
Post Intervention ◽  
Moderator Effects ◽  
Quantitative Synthesis

This review provided a quantitative synthesis of the effectiveness of mental imagery interventions in health behaviour and tested key moderator effects. Thirty-three independent data sets were eligible for inclusion. Mental imagery interventions led to non-trivial, small averaged corrected effect sizes of imagery interventions on post-intervention behaviour (d+ = 0.23) and on psychological predictors of behavior (d+ = 0.08-0.19) and a small-to-medium sized on post-intervention physiological measures (d+ = 0.29). Moderation effects are also reported. Results support effects of mental imagery interventions on health behaviours, identifies the conditions where they may be more effective, and points to how future imagery interventions might be optimized.

The Orchard Plot: Cultivating a Forest Plot for Use in Ecology, Evolution and Beyond

2019 ◽  
Author(s):  
Shinichi Nakagawa ◽  
Malgorzata Lagisz ◽  
Rose E O'Dea ◽  
Joanna Rutkowska ◽  
Yefeng Yang ◽  
...  
Keyword(s):  
Meta Analysis ◽  
R Package ◽  
Effect Sizes ◽  
Forest Plot ◽  
Point Estimates ◽  
Aggregate Effect ◽  
The Individual ◽  
Meta Analyses ◽  
Heterogeneous Effect ◽  
Intuitive Interpretation

‘Classic’ forest plots show the effect sizes from individual studies and the aggregate effect from a meta-analysis. However, in ecology and evolution meta-analyses routinely contain over 100 effect sizes, making the classic forest plot of limited use. We surveyed 102 meta-analyses in ecology and evolution, finding that only 11% use the classic forest plot. Instead, most used a ‘forest-like plot’, showing point estimates (with 95% confidence intervals; CIs) from a series of subgroups or categories in a meta-regression. We propose a modification of the forest-like plot, which we name the ‘orchard plot’. Orchard plots, in addition to showing overall mean effects and CIs from meta-analyses/regressions, also includes 95% prediction intervals (PIs), and the individual effect sizes scaled by their precision. The PI allows the user and reader to see the range in which an effect size from a future study may be expected to fall. The PI, therefore, provides an intuitive interpretation of any heterogeneity in the data. Supplementing the PI, the inclusion of underlying effect sizes also allows the user to see any influential or outlying effect sizes. We showcase the orchard plot with example datasets from ecology and evolution, using the R package, orchard, including several functions for visualizing meta-analytic data using forest-plot derivatives. We consider the orchard plot as a variant on the classic forest plot, cultivated to the needs of meta-analysts in ecology and evolution. Hopefully, the orchard plot will prove fruitful for visualizing large collections of heterogeneous effect sizes regardless of the field of study.

Identification of and Correction for Publication Bias: Comment

2019 ◽  
Author(s):  
Amanda Kvarven ◽  
Eirik Strømland ◽  
Magnus Johannesson
Keyword(s):  
Publication Bias ◽  
False Positive ◽  
Large Scale ◽  
Meta Analysis ◽  
False Positive Rate ◽  
Effect Sizes ◽  
Replication Studies ◽  
Moderate Reduction ◽  
Positive Rate ◽  
Meta Analyses

Andrews &amp; Kasy (2019) propose an approach for adjusting effect sizes in meta-analysis for publication bias. We use the Andrews-Kasy estimator to adjust the result of 15 meta-analyses and compare the adjusted results to 15 large-scale multiple labs replication studies estimating the same effects. The pre-registered replications provide precisely estimated effect sizes, which do not suffer from publication bias. The Andrews-Kasy approach leads to a moderate reduction of the inflated effect sizes in the meta-analyses. However, the approach still overestimates effect sizes by a factor of about two or more and has an estimated false positive rate of between 57% and 100%.

Effectiveness of psychological interventions to improve emotion regulation in youth - a meta-analysis

2019 ◽  
Author(s):  
Bettina Moltrecht ◽  
Jessica Deighton ◽  
Praveetha Patalay ◽  
Julian Childs
Keyword(s):  
Emotion Regulation ◽  
Emotion Dysregulation ◽  
Psychological Intervention ◽  
Meta Analysis ◽  
Age Groups ◽  
Effect Sizes ◽  
What Works ◽  
Large Heterogeneity ◽  
Larger Sample

Background: Research investigating the role of emotion regulation (ER) in the development and treatment of psychopathology has increased in recent years. Evidence suggests that an increased focus on ER in treatment can improve existing interventions. Most ER research has neglected young people, therefore the present meta-analysis summarizes the evidence for existing psychosocial intervention and their effectiveness to improve ER in youth. Methods: A systematic review and meta-analysis was conducted according to the PRISMA guidelines. Twenty-one randomized-control-trials (RCTs) assessed changes in ER following a psychological intervention in youth exhibiting various psychopathological symptoms.Results: We found moderate effect sizes for current interventions to decrease emotion dysregulation in youth (g=-.46) and small effect sizes to improve emotion regulation (g=0.36). Significant differences between studies including intervention components, ER measures and populations studied resulted in large heterogeneity. Conclusion: This is the first meta-analysis that summarizes the effectiveness for existing interventions to improve ER in youth. The results suggest that interventions can enhance ER in youth, and that these improvements correlate with improvements in psychopathology. More RCTs including larger sample sizes, different age groups and psychopathologies are needed to increase our understanding of what works for who and when.

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