Contour-enhanced meta-analysis funnel plots help distinguish publication bias from other causes of asymmetry

Peters, Jaime; Sutton, Alex J.; Jones, David R.; Abrams, Keith R.; Rushton, Lesley

doi:10.1016/j.jclinepi.2007.11.010

Cited by 1,492 publications

(1,048 citation statements)

References 28 publications

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“…The combined OR were estimated from forest plots (Peters et al, 2008). We performed a sensitivity analysis removing one study at a time and analyzing the remaining studies to evaluate the effect of a single study.…”

Section: Resultsmentioning

confidence: 99%

Vitamin B2 Intake and the Risk of Colorectal Cancer: a Meta-Analysis of Observational Studies

Liu¹,

Yu²,

Zhu³

et al. 2015

Asian Pacific Journal of Cancer Prevention

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Asian Pac J Cancer Prev, 16 (3), 909-913 IntroductionIn 2013, colorectal cancer was newly diagnosed in 73,680 males in the United States; 26,300 died of the disease. It was newly diagnosed in 69,140 females and 24,530 died (Siegel et al., 2013). Indeed, colorectal cancer is the third most commonly diagnosed cancer in males and the second in females, with more than 1.2 million new cases and 608,700 deaths estimated to have occurred in 2008 (Center et al., 2009.Vitamin B2 (chemical formula: C17H20N4O6) also known as riboflavin . In fact, the flavin in riboflavin comes from flavus, the Latin word for yellow. (yellow enzymes play a role of hydrogen in the biological oxidation reduction). Vitamin B2 is one of many nutrients required to recycle glutathione, which is one of the most important antioxidants in the human body. (From a chemical standpoint, what B2 does is facilitate the conversion of oxidized glutathione into reduced glutathione.) (Yasuda and Hiraoka, 1999).Riboflavin is unique among the water-soluble vitamins in that milk and dairy products make the greatest contribution to its intake in Western diets. Meat and fish are also good sources of riboflavin, and certain fruit and vegetables, especially dark-green vegetables, contain reasonably high concentrations (Powers, 2003). Vitamin B2 has limited storage , So it need a food supplement Conclusions: This is the first meta-analysis to study links between vitamin B2 and colorectal cancer. We found vitamin B2 intake was inversely associated with risk of colorectal cancer. However, further research and large sample studies need to be conducted to better validate the result.

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Section: Resultsmentioning

confidence: 99%

Vitamin B2 Intake and the Risk of Colorectal Cancer: a Meta-Analysis of Observational Studies

Liu¹,

Yu²,

Zhu³

et al. 2015

Asian Pacific Journal of Cancer Prevention

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“…Here, it appears that many of the potentially ''missing'' samples are located in the insignificant (i.e., the white) area of the distribution. This provides credence to the likelihood that the asymmetry was caused by the suppression of insignificant effect sizes, predominantly from small samples (i.e., publication bias; Peters et al, 2008;Sterne et al, 2011). Finally, once the ''missing'' samples are imputed (with the trim and fill method; see the following section and Figure 1 (c)), it is evident that the imputed samples are small in size and that all except one of their effect sizes are insignificant.…”

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confidence: 82%

“…When this assumption is violated (e.g., sex moderates the magnitude of an effect size), the trim and fill method, as any funnel plotbased method to assess publication bias (e.g., Begg & Mazumdar, 1994;Egger, Smith, Schneider, & Minder, 1997;Peters et al, 2008;, may yield incorrect results (Duval, 2005;Terrin, Schmid, Lau, & Olkin, 2003). Then, trim and fill (and any other funnel plot-based method) can be performed in more homogeneous (i.e., moderator controlled) subgroups of the overall effect size distribution.…”

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confidence: 99%

Publication Bias in the Organizational Sciences

Kepes

Banks

McDaniel

et al. 2012

Organizational Research Methods

358

450

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Publication bias poses multiple threats to the accuracy of meta-analytically derived effect sizes and related statistics. Unfortunately, a review of the literature indicates that unlike meta-analytic reviews in medicine, research in the organizational sciences tends to pay little attention to this issue. In this article, the authors introduce advances in meta-analytic techniques from the medical and related sciences for a comprehensive assessment and evaluation of publication bias. The authors illustrate their use on a data set on employment interview validities. Using multiple methods, including contour-enhanced funnel plots, trim and fill, Egger’s test of the intercept, Begg and Mazumdar’s rank correlation, meta-regression, cumulative meta-analysis, and selection models, the authors find limited evidence of publication bias in the studied data.

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“…18 Funnel plot asymmetry was assessed using Begg and Egger tests. 19,20 If the funnel plot was asymmetrical or the P-value was found to be <0.10 by Egger's test, then publication bias was considered to exist.…”

Section: Methodsmentioning

confidence: 99%

“…This suggests that the observed asymmetry is more likely to be attributable to factors other than publication bias, such as variable study quality. 18 …”

Section: Overall Effect In the Seven Studiesmentioning

confidence: 99%

Efficacy and safety of pharmacotherapy for smoking cessation among pregnant smokers: a meta‐analysis

Myung

Jung

et al. 2012

BJOG

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Background The efficacy and safety of pharmacotherapy for smoking cessation among pregnant smokers has not yet been established.Objective To investigate the efficacy and safety of pharmacotherapy for smoking cessation among pregnant smokers.Search strategy A search was made of PubMed, Embase and CENTRAL in June 2011.Selection criteria Randomised controlled trials (RCTs), quasiRCTs and retrospective or prospective controlled studies were included.Data collection and analysis The main analyses were designed to examine the efficacy of pharmacotherapy for smoking cessation among pregnant smokers based on the longest follow-up data available and from data obtained at the latest available time-point in pregnancy in each study.Main results Of 74 articles identified from the databases, seven studies (five RCTs, one quasi-RCT and one prospective study) involving a total of 1386 pregnant smokers, 732 in the intervention groups and 654 in the control groups, were included in the final analyses. In a fixed-effects meta-analysis of all seven studies based on the longest follow-up data available, pharmacotherapy had a significant effect on smoking cessation (relative risk [RR] 1.80; 95% confidence interval [CI] 1.32-2.44). Subgroup meta-analysis by type of study design also showed similar findings for RCTs (RR 1.48; 95% CI 1.04-2.09) and other types of studies (RR 3.25;). The abstinence rate at late pregnancy in the intervention ranged from 7 to 22.6% (mean abstinence rate 13.0%; 95% CI 10.9-15.2%). A few minor adverse effects and serious adverse effects were reported in several studies.Author's conclusions This study indicates that there may be clinical evidence to support the use of pharmacotherapy for smoking cessation among pregnant smokers. Further RCTs are needed.

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Contour-enhanced meta-analysis funnel plots help distinguish publication bias from other causes of asymmetry

Cited by 1,492 publications

References 28 publications

Vitamin B2 Intake and the Risk of Colorectal Cancer: a Meta-Analysis of Observational Studies

Vitamin B2 Intake and the Risk of Colorectal Cancer: a Meta-Analysis of Observational Studies

Publication Bias in the Organizational Sciences

Efficacy and safety of pharmacotherapy for smoking cessation among pregnant smokers: a meta‐analysis

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