Causal relationship between inflammatory bowel disease and gingivitis or periodontal disease: A two-sample Mendelian randomized analysis

Abstract Background Observational studies have shown that inflammatory bowel disease (IBD), such as ulcerative colitis (UC) and Crohn disease (CD), is associated with gingivitis and periodontal disease (GP). This study aims to investigate whether there is a causal relationship between IBD and GP. Methods This study assessed the causal relationship between IBD and GP through a two-sample Mendelian randomization (MR) study. The required data were obtained through the IEU OpenGWAS project. Instrumental variable screening and the MR and sensitivity analyses were performed using the “TwoSampleMR” R package. Results IBD, UC, and CD may have a causal effect on GP (IBD, inverse variance weighting [IVW] OR = 1.05, 95% CI = 1.00–1.10, P = 0.03; UC, IVW OR = 1.05, 95% CI = 1.00–1.11, P = 0.03; CD, weighted median OR = 1.06, 95% CI = 1.00–1.13, P = 0.04; simple mode OR = 1.15, 95% CI = 1.02–1.31, P = 0.03). Scatterplots, forest plots, and funnel plots showed a significant relationship between IBD and GP and confirmed the robustness of the model. In sensitivity testing, no horizontal pleiotropy or heterogeneity was found in this study. Conclusions This study found a possible causal relationship between IBD (UC and CD) and GP, which deserves to be considered in clinical practice.