Evidence map›Paper›PMID 34338327›Full record

ArticleStatistics in medicine2021

Testing and correcting for weak and pleiotropic instruments in two-sample multivariable Mendelian randomization.

Eleanor Sanderson, Wes Spiller, Jack Bowden

Abstract read
In one paragraph

Article in Statistics in medicine, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 388 papers, 4 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
388citing papers in PubMed, 4 pooled it
–field-weighted citation impact
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

388 citing papers in PubMed, 4 syntheses or guidelines pooled it.

  1. Assessing the causal effects of environmental tobacco smoke exposure: a meta-analytic Mendelian randomization study.Nicotine & tobacco research : official journal of the Society for Research on Nicotine and Tobacco · 2026
    Pooled it
  2. Pooled it
  3. rs762855 single nucleotide polymorphism modulates the risk for diffuse-type gastric cancer in females: a genome-wide association study in the Korean population.Gastric cancer : official journal of the International Gastric Cancer Association and the Japanese Gastric Cancer Association · 2025
    Pooled it
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  20. Mapping the genetically predicted associations between lower-extremity muscle traits and spinal diseases.European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society · 2026
    Article

328 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.

Eleanor SandersonMRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK.ORCID 0000-0001-5188-5775
Wes SpillerMRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK.
Jack BowdenMRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK.ORCID 0000-0003-2628-3304

Funding

Medical Research Council G9815508Medical Research Council MC_PC_15018Medical Research Council MC_PC_19009Medical Research Council MC_UU_00011/1Medical Research Council MC_UU_00011/2Wellcome TrustWellcome Trust 108902/B/15/Z
6 · The paper itself

Abstract

Multivariable Mendelian randomization (MVMR) is a form of instrumental variable analysis which estimates the direct effect of multiple exposures on an outcome using genetic variants as instruments. Mendelian randomization and MVMR are frequently conducted using two-sample summary data where the association of the genetic variants with the exposures and outcome are obtained from separate samples. If the genetic variants are only weakly associated with the exposures either individually or conditionally, given the other exposures in the model, then standard inverse variance weighting will yield biased estimates for the effect of each exposure. Here, we develop a two-sample conditional F-statistic to test whether the genetic variants strongly predict each exposure conditional on the other exposures included in a MVMR model. We show formally that this test is equivalent to the individual level data conditional F-statistic, indicating that conventional rule-of-thumb critical values of

Indexed as

Genetic VariationMendelian Randomization AnalysisCausalityHumansCochran's Q-statisticinstrument strengthinstrument validitymultivariable Mendelian randomizationtwo-sample Mendelian randomization

Identifiers

PMID34338327
PMCPMC9479726

What OpenQuestion holds

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LicenceCC BY
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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.