Independent Associations of Education, Intelligence, and Cognition With Hypertension and the Mediating Effects of Cardiometabolic Risk Factors: A Mendelian Randomization Study

Abstract

Background: Education, intelligence, and cognition are associated with hypertension, but which one plays the most prominent role in the pathogenesis of hypertension and which modifiable risk factors mediate the causal effects remains unknown. Methods: Using summary statistics of genome-wide association studies of predominantly European ancestry, we conducted 2-sample multivariable Mendelian randomization to estimate the independent effects of education, intelligence, or cognition on hypertension (FinnGen study, 70 651 cases/223 663 controls; UK Biobank, 77 723 cases/330 366 controls) and blood pressure (International Consortium of Blood Pressure, 757 601 participants), and used 2-step Mendelian randomization to evaluate 25 potential mediators of the association and calculate the mediated proportions. Results: Meta-analysis of inverse variance weighted Mendelian randomization results from FinnGen and UK Biobank showed that genetically predicted 1-SD (4.2 years) higher education was associated with 44% (95% CI: 0.40–0.79) decreased hypertension risk and 1.682 mm Hg lower systolic and 0.898 mm Hg lower diastolic blood pressure, independently of intelligence and cognition. While the causal effects of intelligence and cognition on hypertension were not independent of education; 6 out of 25 cardiometabolic risk factors were identified as mediators of the association between education and hypertension, ranked by mediated proportions, including body mass index (mediated proportion: 30.1%), waist-to-hip ratio (22.8%), body fat percentage (14.1%), major depression (7.0%), high-density lipoprotein cholesterol (4.7%), and triglycerides (3.4%). These results were robust to sensitivity analyses. Conclusions: Our findings illustrated the causal, independent impact of education on hypertension and blood pressure and outlined cardiometabolic mediators as priority targets for prevention of hypertension attributable to low education.