Quantifying, displaying and accounting for heterogeneity in the meta-analysis of RCTs using standard and generalised Qstatistics

Bowden, Jack; Tierney, Jayne; Copas, Andrew; Burdett, Sarah

doi:10.1186/1471-2288-11-41

Cited by 401 publications

(298 citation statements)

References 44 publications

(54 reference statements)

Supporting

Mentioning

298

Contrasting

Order By: Relevance

“…Fixed-effects models were used to combine ORs of having CRP ≥3 mg/L by comparing participants in the lowest to those in the highest group of Mg intake because there was no significant heterogeneity found among studies. Cochran's Chi-square test was used to examine heterogeneity among included studies and I 2 was computed to determine the degree of inconsistency across studies (19,20). Publication bias was assessed by Egger's test(21) and Begg's test (22).…”

Section: Data Synthesis and Analysismentioning

confidence: 99%

Dietary magnesium intake is inversely associated with serum C-reactive protein levels: meta-analysis and systematic review

Dibaba

Xun

2014

Eur J Clin Nutr

View full text Add to dashboard Cite

Objectives-To quantitatively summarize the association of dietary magnesium (Mg) intake with serum C-reactive protein (CRP) levels in the general population.Methods-Observational and experimental studies through February 2013 were reviewed in PubMed and EMBASE. Additional information was retrieved through Google or hand search of related reference lists. The main outcome is either adjusted geometric mean of CRP or odds ratio (OR) of having serum CRP≥3 mg/L. Meta-regression was used to determine the linear association of dietary Mg intake and adjusted geometric means of CRP levels. A fixed-effects model was used to pool ORs of interest, comparing those in the lowest with those in the highest group of dietary Mg intake.Results-A dataset derived from seven cross-sectional studies including 32,918 participants was quantitatively assessed. A weighted inverse association between Mg intake and serum CRP levels was observed[β coefficient: −0.0028; 95% CI, −0.0043 to −0.0013; P for trend=0.001] from four cross-sectional studies. The pooled OR (95%CI) of having CRP≥3 mg/L was 1.49(1.18 to 1.89) comparing the lowest to the highest group of Mg intake from three studies with data available. Qualitative assessment among five intervention studies also showed a potential beneficial effect of Mg intake on serum CRP levels.Conclusion-This meta-analysis and systematic review indicate that dietary Mg intake is significantly and inversely associated with serum CRP levels. The potential beneficial effect of Mg intake on chronic diseases may be, at least in part, explained by inhibiting inflammation.

show abstract

Section: Data Synthesis and Analysismentioning

confidence: 99%

Dietary magnesium intake is inversely associated with serum C-reactive protein levels: meta-analysis and systematic review

Dibaba

Xun

2014

Eur J Clin Nutr

View full text Add to dashboard Cite

show abstract

“…15 In addition, we used the trim and fill method to estimate the number of potentially missing studies that was required to make the filled funnel plot symmetrical.…”

Section: Data Analysesmentioning

confidence: 99%

The relationship between angiotensin-converting enzyme gene insertion/deletion polymorphism and digestive cancer risk: Insights from a meta-analysis

Yang

Cai

et al. 2015

J Renin Angiotensin Aldosterone Syst

View full text Add to dashboard Cite

Background and objective: The gene encoding angiotensin-converting enzyme (ACE) has been implicated in the development of several malignancies. We aimed to meta-analyze the association of ACE gene insertion/deletion (I/D) polymorphism with digestive cancer risk and seek possible sources of between-study heterogeneity. Methods: Two authors independently assessed eligibility of each retrieved publication and gathered relevant data. Risk estimates were expressed as odds ratio (OR) and 95% confidence interval (CI). Results: Sixteen publications were qualified for analysis, involving 2903 digestive cancer cases and 10,833 controls. Overall analyses failed to show any significance for digestive cancer risk. There was moderate heterogeneity and lower publication bias for overall comparisons. In subgroup analyses, ACE gene II genotype was associated with a 15% reduced risk (OR=0.85, 95% CI: 0.57–1.27, p=0.434) for gastric cancer, but a 16% increased risk (OR=1.16, 95% CI: 0.89–1.52, p=0.273) for colorectal cancer. By source of controls, the I allele appeared to be a protective factor against digestive cancer in population-based studies (OR=0.87, 95% CI: 0.75–1.00, p=0.055) but a risk-conferring factor in hospital-based studies (OR=1.17, 95% CI: 1.01–1.35, p=0.033). Conclusion: Our findings suggested that ACE gene I allele might be a protective factor against gastric cancer, necessitating further confirmation in large, population-based studies.

show abstract

“…We used a random-effects model to conduct all the comparisons. 15 For the meta-regression, the dominant genetic model and homozygote comparison model were mainly used. 16 Dominant genetic models were used to compare the phenotype values of TC+CC genotype individuals to that of TT genotype individuals.…”

Section: Literature Searchmentioning

confidence: 99%

Association of echocardiographic left ventricular structure and −344C/T aldosterone synthase gene variant: A meta-analysis

Wang

Zhou

Zhang

et al. 2014

J Renin Angiotensin Aldosterone Syst

View full text Add to dashboard Cite

Background: Aldosterone synthase (CYP11B2) is one of the most studied candidate genes related to essential hypertension (EH) and left ventricular hypertrophy (LVH). Some studies have focused on the relationship between −344C/T polymorphism (rs1799998) in the CYP11B2 gene and LVH, but the results are controversial. This meta-analysis is purposed to reveal the relationship between the −344C/T and the left ventricular structure and function, including left ventricular end diastolic dimension (LVEDD), left ventricular end systolic diameter (LVESD), left ventricular mass/left ventricular mass index (LVM/LVMI), left ventricular posterior wall thickness (LVPWT), and interventricular septal wall thickness (IVS). Methods: A literature search of PubMed and Embase databases was conducted on articles published before January 27, 2014. The odds ratios with 95% confidence intervals were calculated. Heterogeneity analyses were performed using meta-regression. Tests for publication bias were also performed and biased studies should be removed from subsequent analyses. Results: There were 20 studies with a total of 6780 subjects meeting the inclusion criteria. The main finding was that concentration levels of LVEDD and LVESD were higher in CC homozygous individuals than in TT homozygous individuals in the whole group. In the Asian subgroup, TT homozygous individuals had larger IVS than CC homozygous individuals. In the Caucasian normotension subgroup, CC homozygous individuals had larger LVM/LVMI than TT homozygous individuals. In the Asian essential hypertension subgroup, TT homozygous individuals had larger LVPWT values than CC homozygous individuals. Conclusions: The present findings support the hypothesis that CC homozygous individuals may have greater left ventricular diameters (LVEDD and LVESD) regardless of their ethnicities or physical conditions.

show abstract

Quantifying, displaying and accounting for heterogeneity in the meta-analysis of RCTs using standard and generalised Qstatistics

Cited by 401 publications

References 44 publications

Dietary magnesium intake is inversely associated with serum C-reactive protein levels: meta-analysis and systematic review

Dietary magnesium intake is inversely associated with serum C-reactive protein levels: meta-analysis and systematic review

The relationship between angiotensin-converting enzyme gene insertion/deletion polymorphism and digestive cancer risk: Insights from a meta-analysis

Association of echocardiographic left ventricular structure and −344C/T aldosterone synthase gene variant: A meta-analysis

Contact Info

Product

Resources

About