Education protects against coronary heart disease and stroke independently of cognitive function: evidence from Mendelian randomization

Abstract

Background There is evidence that education protects against cardiovascular disease. However, it is not known whether such an effect is independent of cognition. Methods We performed two-sample Mendelian randomization (MR) analyses to investigate the effect of education and cognition, respectively, on risk of CHD and ischaemic stroke. Additionally, we used multivariable MR to adjust for the effects of cognition and education in the respective analyses to measure the effects of these traits independently of each other. Results In unadjusted MR, there was evidence that education is causally associated with both CHD and stroke risk [CHD: odds ratio (OR) 0.65 per 1-standard deviation (SD; 3.6 years) increase in education; 95% confidence interval (CI) 0.61–0.70, stroke: OR 0.77; 95% CI 0.69–0.86]. This effect persisted after adjusting for cognition in multivariable MR (CHD: OR 0.76; 95% CI 0.65–0.89, stroke OR 0.74; 95% CI 0.59–0.92). Cognition had an apparent effect on CHD risk in unadjusted MR (OR per 1-SD increase 0.80; 95% CI 0.74–0.85), however after adjusting for education this was no longer observed (OR 1.03; 95% CI 0.86–1.25). Cognition did not have any notable effect on the risk of developing ischaemic stroke, with (OR 0.97; 95% CI 0.87–1.08) or without adjustment for education (OR 1.04; 95% CI 0.79–1.36). Conclusions This study provides evidence to support that education protects against CHD and ischaemic stroke risk independently of cognition, but does not provide evidence to support that cognition protects against CHD and stroke risk independently of education. These findings could have implications for education and health policy.

Can increasing years of schooling reduce type 2 diabetes (T2D)?: Evidence from a Mendelian randomization of T2D and 10 of its risk factors

“…In fact, the findings from another recent two-sample MR study, which investigated the impact of education and cognitive ability in a multivariable model in relation to CHD, provide evidence that intelligence is unlikely to be the important driver, at least in relation to CHD. Gill et al found that more schooling years, independent of cognitive ability, are protective: OR 0.76; 95% CI 0.65-0.89 26 .…”

Plasma lipid levels and risk of primary open angle glaucoma: a genetic study using Mendelian randomization

“…These two-sample MR analyses were conducted based on de-identified summary-concentrations data that have been made publicly available; ethical approval was obtained in all original studies. MR analyses assessed the casual effect of an exposure on an outcome by using SNPs as instrumental variables (IVs), in the presence of unmeasured confounding, given that the genotypes are conditionally independent of the disease status [17][18][19]. The following assumptions are made for MR inference: first, the genetic variant has a robust causal relationship with the exposure; second, the genetic variant affects the outcome only through its effect on the exposure; third, the genetic variant and the outcome do not have common causes (Fig.…”

Plasma Lipid Levels and Risk of Primary Open Angle Glaucoma: A Genetic Study Using Mendelian Randomization

“…These two-sample MR analyses were conducted based on de-identi ed summary-concentrations data that have been made publicly available; ethical approval was obtained in all original studies. MR analyses assessed the casual effect of an exposure on an outcome by using SNPs as instrumental variables (IVs), in the presence of unmeasured confounding, given that the genotypes are conditionally independent of the disease status [17][18][19]. The following assumptions are made for MR inference: rst, the genetic variant has a robust causal relationship with the exposure; second, the genetic variant affects the outcome only through its effect on the exposure; third, the genetic variant and the outcome do not have common causes (Fig.…”