Search

Background and Aims: The increasing prevalence of obesity has significantly contributed to the global burden of colorectal cancer and the precancerous colorectal adenoma (CRA). Gut microbiota vary at each stage of colorectal carcinogenesis and participate in energy homeostasis. Elucidating gut microbiotal characteristics in obesity-related CRA may help prevent and treat colorectal tumors; however, this remains unclarified. Therefore, this study investigated the gut microbiota profile of patients with obesity-related CRA. Methods: This hospital setting-based cross-sectional study included 113 participants (66 [without CRA control group] and 37 [with CRA group]; each group was divided into obese and nonobese groups) who underwent screening colonoscopy between June 2019 and January 2020. Gut microbiota were analyzed using 16S rRNA and polymerase chain reaction techniques and the data compared between the aforementioned groups. Results: No between-group difference was observed in the diversity index; however, α diversity was the lowest in the obese CRA group. The CRA group had significantly higher and lower numbers of 26 and 17 genera, respectively. Genus Slackia was significantly lower in the obese CRA group than in the nonobese CRA group. Multivariate analysis of the quartiles according to genus Slackia relative abundance rates revealed that the first quartile was an independent risk factor for CRA (odds ratio, 3.57; 95% confidence interval 1.19–10.7). The proportion of equol reductase-positive participants was lowest in the obese CRA group (P = .04). Multivariate odds ratio for CRA was 5.46 (95% confidence interval 1.35–22.0) for genus Slackia and equol reductase-negative participants. Conclusion: Decreased abundance of genus Slackia and absence of equol reductase potentially influence obesity-related CRA development.