No Causal Relationship Between Helicobacter Pylori Infection and Rosacea: A 2-Sample Mendelian Randomization Study.

Background: Previous studies have shown that patients with rosacea have a higher prevalence of Helicobacter pylori (H. pylori) infection. However, whether H. pylori infection contributes to the development of rosacea remains unclear, and no genetic association studies between the two have been conducted to date. Genome-wide association studies (GWAS) database is a public resource that stores and shares data that aims to identify genetic links to complex diseases, physiological traits, or drug responses. Mendelian randomization (MR) is an epidemiological approach to investigate the effect of the exposure on a specific outcome. Due to the random assortment of single nucleotide polymorphisms (SNPs), they are less likely to be influenced by confounding factors. The MR design can mitigate residual confounding and reverse causation, strengthening the causal inference of the exposure's association with the outcome.

Methods: We use GWAS database and MR design to assess the causal relationship between H. pylori infection and rosacea. Inverse variance weighted (IVW) was the main method in this study, along with MR Egger, simple mode, weighted median, and weighted mode. GWAS data for H. pylori infection and rosacea were retrieved from the Medical Research Council Integrative Epidemiology Unit (MRC-IEU) Open GWAS, GWAS catalog and FinnGen database.

Results: We used H. pylori infection as exposure data and rosacea as outcome data, and all p-values in MR analysis were all greater than 0.05. These conclusions were confirmed by sensitivity analysis.

Conclusion: Our MR analysis provides no evidence of a causal relationship between H. pylori infection and rosacea. This indicates that patients with rosacea may not need routine testing for H. pylori infection and routine eradication of H. pylori may not benefit rosacea patients.