Association between educational attainment and thyroid cancer: evidence from a univariable and multivariable Mendelian randomization study

Thyroid cancer and educational attainment have been related in observational studies. It is unclear if these correlations indicate causative relationships.

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.

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.

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.