Fecal short-chain fatty acids and obesity in a community-based Japanese population: The DOSANCO Health Study

In Western populations, fecal concentrations of short-chain fatty acids (SCFAs) are positively correlated with the prevalence of obesity. However, gut microbiota involved in the production of SCFA varies between races. Our purpose was to investigate the associations between fecal SCFAs and the prevalence of obesity in a community-based Japanese population. We classified a total of 568 participants aged ≥18 into four quartiles of fecal concentrations of SCFA subtypes (acetate, butyrate, and propionate) and total SCFAs to compare the prevalence of obesity, defined as a body mass index ≥ 25.0 kg/m². Using the first quartile SCFA group as a reference, the prevalence ratios of obesity were calculated for each SCFA group through a log-binomial regression model adjusted for major potentially confounding factors including age, sex, exercise habits, total energy intake, and total dietary fiber intake. In the study population, the prevalence of obesity was 35.8%. The prevalence ratios (95% confidence intervals) of obesity in the second, third, and fourth quartile groups of fecal total SCFAs were 1.30 (0.89-1.89), 1.74 (1.23-2.47) and 1.70 (1.19-2.41), respectively, after adjusting for the confounders. Similar positive associations were observed for every subtype. The prevalence ratios (95% confidence intervals) in the fourth quartile groups of fecal acetate, butyrate, and propionate were 1.41 (1.02-1.97), 2.16 (1.49-3.14), and 1.97 (1.35-2.89), respectively, after adjusting for the confounders. In conclusion, our results demonstrated that fecal SCFA concentrations of every subtype were positively associated with the prevalence of obesity in a community-based Japanese population.