BackgroundHeart failure (HF) is a rapidly growing global disease burden with high mortality rates. We aimed to utilize mendelian randomization (MR) analyses to investigate the association between educational attainment (EA) and HF, and to evaluate the contribution of modifiable risk factors as mediators. MethodsWe applied a two-sample MR approach based on the largest genome-wide association studies (GWAS) to investigate the causal relationship between EA and HF. Data collection was conducted in July 2023. We then conducted mediation analyses to explore whether body mass index (BMI), blood pressure, and type 2 diabetes mellitus (T2DM) mediate the effect of EA on HF, and utilized multivariable MR to estimate the proportion of mediation attributed to these factors. ResultsGenetically predicted 3.4 years of additional education was associated with a decrease in the risk of HF (OR 0.76 for each 3.4 years of schooling; 95% CI 0.72, 0.81). BMI, T2DM, systolic blood pressure, and diastolic blood pressure mediated 40.82% (95% CI: 28.86%, 52.77%), 18.00% (95% CI: 12.10%, 23.90%), 11.60% (95% CI: 7.63%, 15.56%), and 7.80% (95% CI: 4.63%, 10.96%) of the EA-HF association, respectively. All risk factors combined were estimated to mediate 63.81% (95% CI: 45.91%, 81.71%) of the effect of EA on HF. ConclusionHigher EA has a protective effect against the risk of HF, and potential mechanisms may include regulation of BMI, blood pressure, and blood glucose. Further research is needed to understand whether interventions targeting these factors could influence the association between EA and HF risk.