The causal effects of education on adult health, mortality and income: evidence from Mendelian randomization and the raising of the school leaving age

Neil M Davies*, Matt Dickson, George Davey Smith, Frank Windmeijer, Gerard j Van den Berg

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

3 Citations (Scopus)

Abstract

Background
On average, educated people are healthier, wealthier and have higher life expectancy than those with less education. Numerous studies have attempted to determine whether education causes differences in later health outcomes or whether another factor ultimately causes differences in education and subsequent outcomes. Previous studies have used a range of natural experiments to provide causal evidence. Here we compare two natural experiments: a policy reform, raising the school leaving age in the UK in 1972; and Mendelian randomization.

Methods
We used data from 334 974 participants of the UK Biobank, sampled between 2006 and 2010. We estimated the effect of an additional year of education on 25 outcomes, including mortality, measures of morbidity and health, ageing and income, using multivariable adjustment, the policy reform and Mendelian randomization. We used a range of sensitivity analyses and specification tests to assess the plausibility of each method’s assumptions.

Results
The three different estimates of the effects of educational attainment were largely consistent in direction for diabetes, stroke and heart attack, mortality, smoking, income, grip strength, height, body mass index (BMI), intelligence, alcohol consumption and sedentary behaviour. However, there was evidence that education reduced rates of moderate exercise and increased alcohol consumption. Our sensitivity analyses suggest that confounding by genotypic or phenotypic confounders or specific forms of pleiotropy are unlikely to explain our results.

Conclusions
Previous studies have suggested that the differences in outcomes associated with education may be due to confounding. However, the two independent sources of exogenous variation we exploit largely imply consistent causal effects of education on outcomes later in life.
Original languageEnglish
Pages (from-to)1878-1886
Number of pages9
JournalInternational Journal of Epidemiology
Volume52
Issue number6
Early online date18 Jul 2023
DOIs
Publication statusPublished - 1 Dec 2023

Bibliographical note

Funding Information:
The Medical Research Council (MRC) and the University of Bristol support the MRC Integrative Epidemiology Unit [MC_UU_00011/1]. N.M.D. was supported via an Economics and Social Research Council (ESRC) Future Research Leaders grant [ES/N000757/1] and via a Norwegian Research Council Grant [295989]. No funding body has influenced data collection, analysis or interpretations.

Funding Information:
The Medical Research Council (MRC) and the University of Bristol support the MRC Integrative Epidemiology Unit [MC_UU_00011/1]. N.M.D. was supported via an Economics and Social Research Council (ESRC) Future Research Leaders grant [ES/N000757/1] and via a Norwegian Research Council Grant [295989]. No funding body has influenced data collection, analysis or interpretations. Acknowledgements

Publisher Copyright:
© 2023 The Author(s). Published by Oxford University Press on behalf of the International Epidemiological Association.

Structured keywords

  • Bristol Population Health Science Institute

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