Periodontitis and the risk of oral, gastric and esophageal cancers: a two‐sample Mendelian randomization study

Background Periodontitis is a common oral disease and the chronic inflammation caused by it may influence the development of cancers in the upper gastrointestinal tract. Many observational studies have established a relationship between the two, but the results are not entirely consistent. Methods Two‐sample MR was performed using publicly available genome‐wide association studies data for periodontitis, oral, gastric and oesophagal cancers. The Inverse Variance Weighting (IVW) method serves as the primary method, with MR Egger, Weighted Median, Simple Model and Weighted Model Algorithm methods as complementary methods to assess genetic causal associations. Cochran Q‐test, MR‐Egger regression and MR polytropic residuals and outliers were used to assess heterogeneity and horizontal pleiotropy. Results IVW results did not support a causal association between periodontitis and oral (OR = 1.00, 95% CI: 1.00, 1.00) and oesophagal cancer (OR = 1.00, 95% CI: 1.00, 1.00). Similarly, there was again no causal association between periodontitis and gastric cancer, which was integrated with an OR of 1.04 (95% CI: 0.97, 1.12). Complementary method results were consistent with IVW and heterogeneity and horizontal pleiotropy were not found in most studies. Conclusions The findings of our MR study do not support a causal relationship between periodontitis and oral, gastric and oesophagal cancers.