A recent study published in the British Medical Journal investigates a cause and effect relationship between education and coronary heart disease.
Coronary heart disease (CHD) is the leading cause of death worldwide. Cause and effect relationships exist for some risk factors for heart disease including smoking, high blood pressure, and low-density lipoprotein (LDL) cholesterol. These risk factors have been widely accepted and are currently incorporated into prevention strategies. Associations between coronary heart disease and other factors such as higher education have been studied but due to methodological limitations, it has not been determined if this relationship is causal. Understanding the nature of the relationship between higher education and coronary heart disease will help in developing better population-based strategies for preventing coronary heart disease. Evidence for cause and effect relationships is usually obtained through randomized controlled trials (RCT), however, RCT is not feasible in this case given the length of time between exposure and outcome (approximately 50 years) pointing to the need for other study designs.
Markers Linked to Higher Education
In a recent study published in the British Medical Journal, a group of researchers used Mendelian randomization to study the causal effect of education and coronary heart disease. In this study, Tillmann and collaborators randomized individuals based on genetic markers that occur naturally and that are known to be linked to higher education. There are 162 of these markers, known as single nucleotide polymorphisms (SNPs). While some individuals receive more of these SNPs, others receive less. Genetic data from two large groups involving 543,733 individuals (both men and women mostly of European origin) were used for the study and were randomized based on their number of SNPs. Exposure to more of the 162 genes was associated with an additional 3.6 years of education.
Based on the Mendelian randomization analysis, it was found that those with an additional 3.6 years of education due to genetic predisposition across the 162 education-related genes have a 33% lower risk of developing coronary heart disease. It was also found that genetic predisposition to longer education was associated with less smoking, lower body mass index, lower triglycerides, and higher high-density lipoprotein (HDL) cholesterol.
Strong Link Between Higher Education and Lower Risk
This study shows that Mendelian randomization can be used to study cause and effect relationships in situations where randomized controlled trials are not feasible. It also found strong support for the causal association between higher education and lower risk of coronary heart disease. While these results point to the need for more education in order to reduce the development of coronary heart disease, there is the need for additional molecular studies to better understand the mechanism by which the 162 education-related genes affect cardiac outcomes. This research cites possible mechanisms as smoking, body mass index, and blood lipids. This study demonstrates that increasing education may result in substantial health benefits.
Written by Asongna T. Folefoc
Tillmann T, Vaucher J, Okbay A, Pikhart H, Peasey A, Kubinova R, Pajak A, Tamosiunas A, Malyutina S, Hartwig FP, Fischer K, Veronesi G, Palmer T, Bowden J, Smith GD, Bobak M, Holmes MV. Education and coronary heart disease: mendelian randomisation study. BMJ 2017;358:j3542 http://dx.doi.org/10.1136/bmj.j3542