RESUMO
BACKGROUND: Thyroid cancer and educational attainment have been related in observational studies. It is unclear if these correlations indicate causative relationships. METHODS: Using large-scale genome-wide association studies (GWAS) datasets, we conducted an univariable and multivariable Mendelian randomization (MR) study to assess a potential connection between educational attainment and thyroid cancer. The inverse-variance weighted (IVW) analysis method is used as our primary outcome. Additionally, we carry out several sensitivity analyses to evaluate the pleiotropy and robustness of the causal estimates. RESULTS: Univariate MR study shows 4.2 years of additional education is associated with a 41.4% reduction in thyroid cancer risk (OR = 0.586; 95% CI: 0.378-0.909; P = 0.017). Further multivariable MR analysis revealed that body mass index (BMI) acted as a partial mediating factor in the protective impact of higher educational attainment against thyroid cancer. CONCLUSION: This MR study provided genetic evidence that longer education attainment is related to a lower risk of thyroid cancer. Strategies of expanding education may reduce the burden of thyroid cancer in the world.