Evidence map›Paper›PMID 16216822›Full record

SynthesisBMJ (Clinical research ed.)2005

Meta-analysis of MTHFR 677C->T polymorphism and coronary heart disease: does totality of evidence support causal role for homocysteine and preventive potential of folate?

Sarah J Lewis, Shah Ebrahim, George Davey Smith

Open access · bronzeAbstract readMeta-AnalysisReview
PubMed Full text at PMC Publisher
In one paragraph

Synthesis in BMJ (Clinical research ed.), 2005. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 94 papers, 9 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
94citing papers in PubMed, 9 pooled it
20.5field-weighted citation impact, top 1% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

94 citing papers in PubMed, 9 syntheses or guidelines pooled it, 307 citations in OpenAlex.

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34 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

3 authors at 1 institution in 1 country.

Sarah J LewisDepartment of Social Medicine, University of Bristol, Bristol BS8 2PR. s.j.lewis@bristol.ac.uk
Shah Ebrahim
George Davey Smith
University of Bristol · GB

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

objectivesTo investigate the association between the MTHFR 677C-->T polymorphism and coronary heart disease, assessing small study bias and heterogeneity between studies. DATA SOURCES: Medline and Embase citation searches between January 2001 and August 2004; no language restrictions. STUDY SELECTION: Case-control and prospective studies of association between MTHFR 677C-->T variant and myocardial infarction, coronary artery occlusion, or both; 80 studies were included. DATA EXTRACTION: Data on genotype frequency and mean homocysteine concentrations by genotype were extracted. Odds ratios were calculated for TT genotype versus CC genotype. Heterogeneity was explored, with stratification by geographical region of the study samples, and meta-regression by difference in mean serum homocysteine concentrations (CC minus TT genotypes) was carried out.

results26,000 cases and 31,183 controls were included. An overall random effects odds ratio of 1.14 (95% confidence intervals 1.05 to 1.24) was found for TT versus CC genotype. There was strong evidence of heterogeneity (P < 0.001, I2 = 38.4%), which largely disappeared after stratification by geographical region. Odds ratios in Europe, Australia, and North America attenuated towards the null, unlike those in the Middle East and Asia.

conclusionsNo strong evidence exists to support an association of the MTHFR 677 C-->T polymorphism and coronary heart disease in Europe, North America, or Australia. Geographical variability may be due to higher folate intake in North America and Europe or to publication bias. The conclusion drawn from previous meta-analyses that folic acid, through lowering homocysteine, has a role in prevention of cardiovascular disease is in some doubt.

Indexed as

Case-Control StudiesCoronary StenosisFolic AcidGenotypeGlobal HealthHomocysteineHumansMethylenetetrahydrofolate Reductase (NADPH2)Myocardial InfarctionPolymorphism, GeneticProspective StudiesResidence CharacteristicsFolic AcidHomocysteineMethylenetetrahydrofolate Reductase (NADPH2)

Identifiers

PMID16216822
PMCPMC1283183
OpenAlexW2100997592

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.