Oral Health and the Altered Colonic Mucosa-Associated Gut Microbiota

Systemic diseases have been associated with oral health and gut microbiota. We examined the association between oral health and the community composition and structure of the adherent colonic gut microbiota.

We obtained 197 snap-frozen colonic biopsies from 62 colonoscopy-confirmed polyp-free individuals. Microbial DNA was sequenced for the 16S rRNA V4 region using the Illumina MiSeq, and the sequences were assigned to the operational taxonomic unit based on SILVA. We used a questionnaire to ascertain tooth loss, gum disease, and lifestyle factors. We compared biodiversity and relative abundance of bacterial taxa based on the amount of tooth loss and the presence of gum disease. The multivariable negative binomial regression model for panel data was used to estimate the association between the bacterial count and oral health. False discovery rate-adjusted P value (q value) < .05 indicated statistical significance.

More tooth loss and gum disease were associated with lower bacterial alpha diversity. The relative abundance of Faecalibacterium was lower (q values < .05) with more tooth loss. The association was significant after adjusting for age, ethnicity, obesity, smoking, alcohol use, hypertension, diabetes, and the colon segment. The relative abundance of Bacteroides was higher in those with gum disease.

Oral health was associated with alteration in the community composition and structure of the adherent gut bacteria in the colon. The reduced anti-inflammatory Faecalibacterium in participants with more tooth loss may indicate systemic inflammation. Future studies are warranted to confirm our findings and investigate the systemic role of Faecalibacterium.