Intelligence and education are predictive of better physical and mental health, socioeconomic position (SEP), and longevity. However, these associations are insufficient to prove that intelligence and/or education cause these outcomes. Intelligence and education are phenotypically and genetically correlated, which makes it difficult to elucidate causal relationships. We used univariate and multivariable Mendelian randomization to estimate the total and direct effects of intelligence and educational attainment on mental and physical health, measures of socioeconomic position, and longevity. Both intelligence and education had beneficial total effects. Higher intelligence had positive direct effects on income and alcohol consumption, and negative direct effects on moderate and vigorous physical activity. Higher educational attainment had positive direct effects on income, alcohol consumption, and vigorous physical activity, and negative direct effects on smoking, BMI and sedentary behaviour. If the Mendelian randomization assumptions hold, these findings suggest that both intelligence and education affect health.
The causal effects of education on behavioural risk factors, morbidity and all-cause and cause-specific mortality: evidence from the 500,000 participants of the UK biobank.
Research question: what are the causal effects of education on morbidity and cause specific mortality?
Outcomes: all-cause and cause-specific mortality, coronary heart disease, lung cancer and income.
Synopsis: On average people with more years of education live longer and are healthier. We do not know whether this is because more educated people are less likely to engage in risky behaviours such as smoking, or if there are other differences, such as cognition or social class, which cause some people to be both healthier and more educated.
We will address this hypothesis using statistical techniques for differentiating causation and correlation. Low education is a major risk factor for a wide range of diseases.
We will use data from the UK biobank to improve our understanding of how individuals' educational choices early in life affect their long term health outcomes.
Ultimately, knowledge from this project will help policy makers and practitioners mitigate these differences. Furthermore, our results will provide evidence about the consequences of the recent decisions to further increase the minimum school leaving age to 18 and to widen access to higher education. We will use data on all individuals from biobank with information on date and country of birth and age at which they left full time education.
We will investigate differences in health outcomes by duration of education. We will present adjusted results adjusted for known confounders (such as income, cognition).
We will use the raising of the school leaving age in 1972 and genetic variants known to associate with education as a natural experiments (instrumental variable) for educational achievement to identify the causal effects of education. We will use participants born outside the UK as a negative control population to provide further validation of our methods (1). We do not expect the changing of the school leaving age to affect the educational attainment of individuals born outside of the UK.
|Lead investigator:||Dr Neil Davies|
|Lead institution:||University of Bristol|
|1763||Multivariable two-sample Mendelian randomization estimates of the effects of intelligence and education on health||Davies, N. et al||2019||eLife. 2019|