Causal association between Helicobacter pylori infection and Sjogren's syndrome: a bidirectional Mendelian randomization analysis

Background The results of observational studies indicate a potential link between Helicobacter pylori infection and Sjogren's syndrome (SS), but the causal relationship between them remains unknown. This study applied Mendelian randomization (MR) to evaluate this relationship. Method Genome-wide association study (GWAS) summary statistics on H. pylori infection [sample size=8735 (EBI, https://gwas.mrcieu.ac.uk/)] and SS [sample size=368,028 (cases=2495, controls=365533) (FinnGen, https://r9.finngen.fi/)] were analyzed. We used bidirectional MR to evaluate the association between H. pylori infection and SS and identify causation. The major MR analysis method was inverse-variance weighted (IVW) MR, supplemented by MR-Egger and weighted median approaches. In addition, the stability and reliability of the results were tested using the retention method, heterogeneity test, and horizontal gene pleiotropy test. Results Evidence of the impact of H. pylori infection on SS risk was found in the IVW results [odds ratio (OR)=1.6705; 95% confidence interval (CI)=1.0966 to 2.5446; P=0.0168]. Evidence of the impact of SS on H. pylori infection risk was also found (OR=1.0158; 95% CI=1.0033 to 1.0285; P=0.0128). Conclusion The results of MR analysis support a causal association between H. pylori infection and SS and indicate that SS can lead to a greater risk of H. pylori infection. Our research will support the development of novel approaches for continued H. pylori and SS-related research and therapy that consider the genetic relationship between H. pylori infection and SS.