Exploring the Causal Relationship between Airborne Particulate Matter and Ulcerative Colitis: A Two-Sample Mendelian Randomization Study

BackgroundExisting research has demonstrated links between airborne particulate matter and ulcerative colitis (UC). This study aims to explore the causal relationship between specific air pollutants and UC risk, considering the opposing effects reported in previous studies. MethodsWe conducted a two-sample Mendelian randomization study to investigate the association between exposure to airborne particulate matter and UC risk. Genetic datasets for airborne particulate matter and UC were derived from genome-wide association studies. We used inverse variance weighted (IVW), weighted median, MR-Egger, and Wald Ratio methods to assess the causality between particulate matter exposure and UC. ResultsThe analysis revealed a significant positive correlation between PM2.5 exposure and UC risk (OR: 3.6; 95% CI: [1.2–11.3]; P = 0.026). The statistical strength for causal determination via the IVW approach was 0.87. Assessments using Cochran's Q test, MR-Egger intercept, MR-PRESSO, and leave-one-out sensitivity analyses did not identify notable heterogeneity, pleiotropy, or biases in the overall relationship between PM2.5 and UC. ConclusionThe findings suggest a probable causal link between PM2.5 exposure and UC risk. Recognizing the underlying pathogenesis of UC is essential for targeted prevention and treatment strategies in regions with poor air quality.