Association Between Periodontal Disease And The Risk Of Colorectal Cancer:A Meta-analysis

BACKGROUND: Colorectal cancer is a common gastrointestinal cancer.Statistical data show that the incidence of colorectal cancer ranks third among all malignancies in the world,with the second highest rate of males and the second highest rate among females caused by cancer death.China's health statistics shows that the incidence of colorectal cancer is 20.27 per 100,000 people.Among all malignant tumors,it ranks fourth and makes the fourth cause of cancer death.Colorectal cancer has brought a heavy economic and physical burden to people all over the world.Even though colorectal cancer is a curable gastrointestinal cancer,it is limited to early diagnosis.Due to insufficient early monitoring,there are still a number of patients diagnosed with colorectal cancer not in early stage,although actively cooperate with the treatment,the outcome of losing both life and wealth is not uncommon.Therefore,early prevention and treatment of colorectal cancer is of great significance.Affected by the traditional concept of “diseases from the mouth”,people have effectively reduced the incidence of many digestive diseases by changing bad dietary habits and adjusting dietary structures.From this point of view,are oral diseases associated with colorectal cancer? The basis for consideration is as below: Mouth as the entrance of the digestive tract,its health affects the entire digestive process of food to some extent.Poor oral conditions often cause people to make adaptive changes in the choice of food types and “primary processing” of foods in the mouth.This not only affects the acquisition of nutrients,and may also create inadequate preparation of food before passing through other parts of the digestive tract,which increases the digestion and absorption burden of the digestive tract.In addition,under normal circumstances,there is resident flora in the oral cavity,and these bacteria are safe to humans.However,bacteria in the oral cavity change in type and quantity,and enter the rest of the digestive tract with swallowing.These factors may lead to changes in the digestive tract tissue itself and the environment within the digestive tract,which in turn may cause chronic inflammation of the digestive tract,tumors and other diseases.Some domestic and foreign scholars have done some basic and clinical researches in this area and have discovered some encouraging results.However,the results of clinical studies are divergent and there are no unanimous conclusions.Therefore,it is necessary to summarize and evaluate the current research on the correlation between periodontal disease and colorectal cancer,and to find out whether there is a correlation between periodontal disease and colorectal cancer.Meta-analysis,a commonly used method of evidence-based medicine,can be used in this study to increase sample size,improve test effectiveness,and come to more reliable conclusions.OBJECTIVES: To systematically evaluate the association between periodontal disease and the risk of colorectal cancer using meta-analysis.METHODS: Computer-based search of Cochrane Library,PubMed,EMBASE,WanFang Data,and CNKI databases was performed in cohort or case-control studies to investigate the association between periodontal disease and colorectal cancer risk up to December 31 th,2017.Two trained researchers independently searched for documents based on preliminary search formulas,and adjusted and optimized the search formula based on the search results to ensure that they were as complete as possible.Compare the results of the two search results and find the possible reasons for differences,determine the final search results after the discussion.The resulting document was imported into the Endnote software,eliminating duplicate documents.Then,by reading the titles and/or abstracts,literatures which are not relevant to the study are preliminarily excluded.Further read the full text of the preliminary screening and exclude research that has little or no data to extract.Based on the established inclusion exclusion criteria,confirm the inclusion of the literature.Check the references included in the literature for possible references.The quality of the included literature was evaluated,research data were extracted and the risk of bias of the included studies was assessed.All operations were conducted independently by two researchers and the results were cross-checked.The differences were solved by discussion.If the two researchers can't come to an agreement,the third-party opinions were solicited.The data extracted from the included studies included Risk Ratio(RR)or Odds Ratio(OR)or Hazard Ratio(HR),and 95% confidence intervals(CI),using RevMan 5.3 software performed a meta-analysis.RESULTS: Final inclusion of 5 prospective cohort studies.Meta-analysis based on correction showed that periodontal disease increased the risk of colorectal cancer,but it was not statistically significant [RR=1.14,95% CI(0.88,1.49),P=0.32].The subgroup analysis results are consistent with the overall results.Sensitivity analysis showed that the results are robust.CONCLUSIONS: This meta-analysis showed that periodontal disease increased the risk of colorectal cancer but was not statistically significant.The available data is insufficient to demonstrate that periodontal disease is associated with colorectal cancer.