Oral dysbiosis and risk of gastrointestinal cancers: A systematic review and meta-analysis of longitudinal studies

Background

Poor oral health and oral dysbiosis were found to be associated with cancers, especially of the gastrointestinal (GI) system. But the cause-and-effect relationship and the effect of the risk are not yet known due to scarcity of literature. Understanding such risk relationship can contribute to an integrated multi-disciplinary approach for GI cancer prevention.

Aim

The aim of the present systematic review and meta-analysis is to assess the role of oral dysbiosis on increasing the risk of digestive system cancers.

Objective

To evaluate the effect of poor oral health on increasing the risk of gastrointestinal cancers.

Methods

We conducted a systematic search following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines in databases PubMed, Elsevier, Wiley’s online library and Web of Science from inception to February 2023 to include recent cohort studies that assessed the association between poor oral health and the risk of cancer. We assessed bias using the New Castle Ottawa scale. We used inferential statistics to describe the effect of oral dysbiosis on gastrointestinal cancers. We performed a sub-group analysis to assess the effect of oral conditions on individual cancers.

Results

We included 10 longitudinal studies in the meta-analysis. The overall effect size of poor oral health and GI cancer risk was hazard’s ratio (HR) =1.30 (95% CI: [1.14, 1.46]) (p<0.001) (I² = 68.78). Sub-group analysis indicated that poor oral health increases the risk of esophageal cancer HR=1.61 (95% CI: [1.37, 1.85]), stomach cancer HR=1.33 (95% CI: [1.08, 1.58]), pancreatic cancer HR=1.90 (95% CI; [1.29, 2.50]) and colorectal and hepatocellular carcinoma HR=1.16 (95% CI: [1.08, 1.23]).

Conclusion

The meta-analysis indicated that poor oral health was significantly associated with increasing the risk of GI cancers.

Graphical Abstract