Causal relationship between educational attainment and Hashimoto's thyroiditis: a two-sample mendelian randomization study.

Abstract

Introduction: The etiology of Hashimoto's thyroiditis (HT) is diverse. The correlation between educational attainment (EA) and health is also a research hotspot. This study explores the relationship between EA and HT from a genetic perspective.

Material and methods: Summary data on EA and HT were sourced from the MRC Integrative Epidemiology Unit (IEU) Open Genome-Wide Association Studies (GWAS) database. Utilizing single nucleotide polymorphisms (SNPs) that are strongly associated with EA as instrumental variables, we estimated the causal relationship between EA and HT through two-sample mendelian randomization (TSMR) analysis, including inverse variance weighted (IVW), MR-Egger, weighted median, simple mode, and weighted mode approaches. Heterogeneity was assessed using Cochran's Q test. Pleiotropy was evaluated via the MR-Egger intercept and the global test value from MR pleiotropy residual sum and outlier (MR-PRESSO). Additionally, a leave-one-out method along with funnel plot analysis was employed to examine stability.

Results: The IVW method revealed a significant correlation between EA and HT [odds ratio (OR): 0.933, 95% confidence interval (CI): 0.898 to 0.970, p < 0.001], while similar evidence was observed using the weighted median method (OR: 0.938, 95% CI: 0.886 to 0.993, p = 0.029). Cochran's Q test indicated no heterogeneity (p > 0.05). Both the intercept value and global test result suggested an absence of pleiotropy (p > 0.05). The leave-one-out approach did not identify any individual SNP exerting a significant influence on the overall effect estimate. Furthermore, scatter points in the funnel plot exhibited near symmetry, indicating robust study stability.

Conclusion: EA is associated with lower risk of HT.