Associations of the Colon Tissue Microbiome and Circulating Bile Acids With Colorectal Adenoma Among Average-Risk Women.

OBJECTIVE

The gut microbiome and bile acids (BAs) likely influence colorectal cancer (CRC) development and disparities. We conducted a nested case-control study of the associations of the colon tissue microbiome and circulating BAs with colorectal adenoma prevalence in the previously conducted multi-center Colorectal Neoplasia Screening with Colonoscopy in Average-Risk Women Regional Navy/Army Medical Centers study (CONCeRN).

METHODS

We individually matched 143 women with adenoma to 279 without adenoma. Using 16S rRNA gene sequencing, we assessed alpha and beta diversity, taxonomic abundance, and co-abundance groups (CAGs). Fasting serum was analyzed for 13 primary and secondary BAs.

RESULTS

The presence of oral-originating Porphyromonas was positively associated with adenomas (odds ratio [OR] and 95% confidence interval [CI] = 2.50 [1.18, 5.30]; p = 0.02). Race and study center explained statistically significant percentages of variation in the beta diversity matrices. BAs were generally positively associated with adenomas, though these results were not statistically significant.

DISCUSSION

Overall, our findings suggest the colon tissue microbiome may differ by race and geography, and that certain oral-originating bacteria may be positively associated with adenomas.