A two-sample bidirectional Mendelian randomization study on causal relationship between educational level and primary hypertension

Objective To investigate the causal relationship between educational level and primary hypertension.

Methods Two-sample bidirectional Mendelian randomization (MR) analysis was conducted using publicly available summary data from Genome-Wide Association Studies (GWAS). Genetic data on educational level and primary hypertension were obtained from databases. The inverse variance weighted (IVW) method, weighted median (WM) method, MR Egger regression method, simple model method, and weighted model method were employed, with IVW as the primary analysis method and the others as secondary methods, to evaluate the causal relationship between educational level and primary hypertension. Cochran's Q test was applied to assess heterogeneity among instrumental variables, and I² was used for heterogeneity verification. Horizontal pleiotropy was tested using the MR-Egger intercept method and MR-PRESSO method. Sensitivity analysis was performed using the leave-one-out method.

Results Forward MR analysis: the IVW results showed that an increase in educational level (OR=0.998, 95%CI, 0.995 to 1.000, P=0.018) reduced the risk of primary hypertension. WM analysis also indicated that an increase in educational level (OR=0.997, 95%CI, 0.994 to 1.000, P=0.042) similarly reduced the risk of primary hypertension. The results of MR Egger, simple model, and weighted model analyses all showed that an increase in educational level did not reduce the risk of primary hypertension (P>0.05), but their β values were consistent with the directions of IVW and WM. Reverse MR analysis: IVW, WM, MR Egger, simple model, and weighted model analyses all showed no causal relationship between primary hypertension and educational level (P>0.05).

Conclusion There is a causal relationship between educational level and primary hypertension, and an increase in educational level reduces the risk of primary hypertension.