# Assessing the Causal Association Between COVID-19 and Graves Disease: Mendelian Randomization Study

## TL;DR

This study finds no causal link between COVID-19 and Graves disease using genetic data analysis.

## Contribution

The study uses Mendelian randomization with the largest dataset to date to assess the causal relationship between COVID-19 and Graves disease.

## Key findings

- No causal relationship was found between COVID-19 susceptibility and Graves disease.
- Tests for pleiotropy and heterogeneity supported the lack of a causal link.
- Results suggest no significant impact of COVID-19 on the onset or severity of Graves disease.

## Abstract

Graves disease (GD) is an autoimmune thyroid disorder characterized by hyperthyroidism and autoantibodies. The COVID-19 pandemic has raised questions about its potential relationship with autoimmune diseases like GD.

This study aims to investigate the causal association between COVID-19 and GD through Mendelian randomization (MR) analysis and assess the impact of COVID-19 on GD.

We conducted an MR study using extensive genome-wide association study data for GD and COVID-19 susceptibility and its severity. We used stringent single nucleotide polymorphism selection criteria and various MR methodologies, including inverse-variance weighting, MR-Egger, and weighted median analyses, to assess causal relationships. We also conducted tests for directional pleiotropy and heterogeneity, as well as sensitivity analyses.

The MR analysis, based on the largest available dataset to date, did not provide evidence supporting a causal relationship between COVID-19 susceptibility (odds ratio [OR] 0.989, 95% CI 0.405‐2.851; P=.93), COVID-19 hospitalization (OR 0.974, 95% CI 0.852‐1.113; P=.70), COVID-19 severity (OR 0.979, 95% CI 0.890‐1.077; P=.66), and GD. Tests for directional pleiotropy and heterogeneity, as well as sensitivity analyses, supported these findings.

This comprehensive MR study does not provide sufficient evidence to support a causal relationship between COVID-19 and the onset or exacerbation of GD. These results contribute to a better understanding of the potential association between COVID-19 and autoimmune diseases, alleviating concerns about a surge in autoimmune thyroid diseases due to the pandemic. Further research is warranted to explore this complex relationship thoroughly.