Exploring the Relationship Between Protein-Level Ratios (rQLTs) and Duodenal Ulcer.

To explore the associations between protein-level ratios (rQLTs) and duodenal ulcer (DU) risk using Mendelian randomization (MR), colocalization, and pathway analysis approaches. A bidirectional MR approach was used to identify molecular targets linking rQLTs with DU, employing the inverse variance weighted (IVW) method for causal estimation. Colocalization analysis ensured the reliability of inferred causal relationships. Gene interaction networks were constructed via STRING, and key regulatory hub-genes were identified through Cytoscape analysis. Significant inverse associations were found between rQLT-ACE2/GGT1 (Angiotensin-converting enzyme 2/γ-glutamyl transpeptidase 1) (IVW, OR (95% CI) = 0.754 (0.674-0.843), adjusted PIVW = 0.0005), and DU risk in the East Asian (Japanese) population. No statistically significant associations were observed in the European population. The findings indicate a genetic inverse association between rQLT-ACE2/GGT1 and DU risk in the East Asian (Japanese) population, while no corresponding association was observed in Europeans. These results provide genetic evidence consistent with a potential association rather than causal inference or biomarker validation. This study does not support conclusions regarding diagnostic or therapeutic utility at this stage.