# Periodontitis as a risk factor for colorectal cancer: systematic review and meta-analysis

## TL;DR

This study finds that periodontitis is not a general risk factor for colorectal cancer, but it may increase the risk in men.

## Contribution

The study identifies a gender-specific risk of colorectal cancer associated with periodontitis in men.

## Key findings

- Periodontitis is not a general risk factor for colorectal cancer (RR=1.34; 95% CI: 0.96-1.89).
- Men with periodontitis have a 32% increased risk of colorectal cancer (RR=1.32; 95% CI: 1.16-1.50).
- The evidence for the general population has very low certainty, while the evidence for men has moderate certainty.

## Abstract

Primary studies on the association between periodontitis and colorectal cancer (CRC) may have insufficient statistical power to reach a reliable conclusion. In this regard, the present systematic review and meta-analysis were conducted to determine whether periodontitis is a risk factor for CRC.

A systematic search was carried out in five databases, which included cohort and case-control studies published up to July 3, 2024, in which periodontitis was evaluated as a risk factor for CRC using relative risk (RR), hazard ratio (HR) or odds ratio (OR). The Newcastle-Ottawa Scale (NOS) was used to assess the risk of bias, and the GRADE system was used to determine the certainty of the evidence.

Of 1476 articles retrieved, 8 cohort studies were included for qualitative analysis and meta-analysis. The overall synthesis showed that periodontitis is not a risk factor for CRC (RR=1.34; 95% CI: 0.96-1.89; p<0.09; I2=95%). In addition, subgroup analyses were performed according to gender, periodontitis diagnostic methods, and risk of bias, which led to the finding of an increased risk of CRC of 32% only for men with periodontitis (RR=1.32; 95% CI: 1.16-1.50; p<0.00001; I2=0%).

Periodontitis is not a risk factor for CRC, with very low certainty of evidence. However, the analysis of subgroups by gender showed that it is a risk factor for CRC in men, with moderate certainty of evidence.

Key words:Periodontitis, periodontal diseases, colorectal neoplasms, colorectal cancer, colorectal carcinoma, colorectal tumor.