Evidence map›Paper›PMID 39924502›Full record

ArticleBMC global and public health2025

Investigating causal effects of income on health using two-sample Mendelian randomisation.

Erik Igelström, Marcus R Munafò, Ben M Brumpton, Neil M Davies, George Davey Smith, Pekka Martikainen, Desmond Campbell, Peter Craig, Jim Lewsey, S Vittal Katikireddi

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In one paragraph

Article in BMC global and public health, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
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1 · What the graph read from it

What it found

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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

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3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

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4 · The record

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5 · Who and what money

Authors and funding

10 authors.

Erik IgelströmMRC/CSO Social and Public Health Sciences Unit, School of Health and Wellbeing, University of Glasgow, Glasgow, UK. Erik.Igelstrom@glasgow.ac.uk.
Marcus R MunafòMRC Integrative Epidemiology Unit (IEU), Bristol Medical School, University of Bristol, Bristol, UK.
Ben M BrumptonBristol Medical School, Population Health Sciences, University of Bristol, Bristol, UK.
Neil M DaviesMRC Integrative Epidemiology Unit (IEU), Bristol Medical School, University of Bristol, Bristol, UK.
George Davey SmithMRC Integrative Epidemiology Unit (IEU), Bristol Medical School, University of Bristol, Bristol, UK.
Pekka MartikainenPopulation Research Unit, Faculty of Social Sciences, University of Helsinki, Helsinki, Finland.
Desmond CampbellMRC/CSO Social and Public Health Sciences Unit, School of Health and Wellbeing, University of Glasgow, Glasgow, UK.
Peter CraigMRC/CSO Social and Public Health Sciences Unit, School of Health and Wellbeing, University of Glasgow, Glasgow, UK.
Jim LewseyHealth Economics and Health Technology Assessment, School of Health and Wellbeing, University of Glasgow, Glasgow, UK.
S Vittal KatikireddiMRC/CSO Social and Public Health Sciences Unit, School of Health and Wellbeing, University of Glasgow, Glasgow, UK.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundIncome is associated with many health outcomes, but it is unclear how far this reflects a causal relationship. Mendelian randomisation (MR) uses genetic variation between individuals to investigate causal effects and may overcome some of the confounding issues inherent in many observational study designs.

methodsWe used two-sample MR using data from unrelated individuals to estimate the effect of log occupational income on indicators of mental health, physical health, and health-related behaviours. We investigated pleiotropy (direct effects of genotype on the outcome) using robust MR estimators, CAUSE, and multivariable MR including education as a co-exposure. We also investigated demographic factors and dynastic effects using within-family analyses, and misspecification of the primary phenotype using bidirectional MR and Steiger filtering.

resultsWe found that a 10% increase in income lowered the odds of depression (OR 0.92 [95% CI 0.86-0.98]), death (0.91 [0.86-0.96]), and ever-smoking (OR 0.91 [0.86-0.96]), and reduced BMI (- 0.06 SD [- 0.11, - 0.003]). We found little evidence of an effect on alcohol consumption (- 0.02 SD [- 0.01, 0.05]) or subjective wellbeing (0.02 SD [- 0.003, 0.04]), or on two negative control outcomes, childhood asthma (OR 0.99 [0.87, 1.13]) and birth weight (- 0.02 SD, [- 0.01, 0.05]). Within-family analysis and multivariable MR including education and income were imprecise, and there was substantial overlap between the genotypes associated with income and education: out of 36 genetic variants significantly associated with income, 29 were also significantly associated with education.

conclusionsMR evidence provides some limited support for causal effects of income on some mental health outcomes and health behaviours, but the lack of reliable evidence from approaches accounting for family-level confounding and potential pleiotropic effects of education places considerable caveats on this conclusion. MR may nevertheless be a useful complement to other observational study designs since its assumptions and limitations are radically different. Further research is needed using larger family-based genetic cohorts, and investigating the overlap between income and other socioeconomic measures.

Indexed as

Causal inferenceGenetic epidemiologyHealth inequalitiesIncomeMendelian randomizationSocial determinants of health

Identifiers

PMID39924502
PMCPMC11809080

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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.