## 3 Results
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & **Total SCFAs** & **Acetate** & **Propionate** & **Butyrate** & **Isobutyrate** & **OTU Richness** \\ \hline \hline
**Adiposity** & & & & & & \\ \hline BMI & 0.28 \({}^{*}\) & 0.26 \({}^{*}\) & 0.29 \({}^{*}\) & 0.25 \({}^{*}\) & 0.13 \({}^{*}\) & \(-\)0.11 \({}^{*}\) \\ Body fat & 0.13 \({}^{*}\) & 0.12 \({}^{*}\) & 0.14 \({}^{*}\) & 0.11 \({}^{*}\) & 0.09 & \(-\)0.06 \\ Waist circumference & 0.26 \({}^{*}\) & 0.23 \({}^{*}\) & 0.28 \({}^{*}\) & 0.24 \({}^{*}\) & 0.14 \({}^{*}\) & \(-\)0.19 \({}^{*}\) \\ \hline \multicolumn{5}{c}{**Blood chemistry**} \\ \hline HDL & \(-\)0.10 \({}^{*}\) & \(-\)0.08 & \(-\)0.13 \({}^{*}\) & \(-\)0.11 \({}^{*}\) & \(-\)0.06 & 0.15 \({}^{*}\) \\ LDL & \(-\)0.02 & \(-\)0.02 & \(-\)0.01 & 0.00 & 0.01 & 0.03 \\ VLDL & 0.14 \({}^{*}\) & 0.12 \({}^{*}\) & 0.18 \({}^{*}\) & 0.14 \({}^{*}\) & 0.02 & \(-\)0.15 \({}^{*}\) \\ Triglycerides & 0.14 \({}^{*}\) & 0.12 \({}^{*}\) & 0.18 \({}^{*}\) & 0.15 \({}^{*}\) & 0.02 & \(-\)0.16 \({}^{*}\) \\ hs-CRP & 0.18 \({}^{*}\) & 0.16 \({}^{*}\) & 0.19 \({}^{*}\) & 0.24 \({}^{*}\) & 0.14 \({}^{*}\) & \(-\)0.11 \({}^{*}\) \\ Glucose & 0.10 & 0.10 & 0.12 \({}^{*}\) & 0.04 & 0.05 & \(-\)0.06 \\ HbA1c & 0.12 \({}^{*}\) & 0.14 \({}^{*}\) & 0.10 & 0.06 & 0.11 \({}^{*}\) & 0.02 \\ Insulin & 0.18 \({}^{*}\) & 0.16 \({}^{*}\) & 0.19 \({}^{*}\) & 0.17 \({}^{*}\) & 0.11 \({}^{*}\) & \(-\)0.10 \\ HOMA-IR & 0.09 & 0.07 & 0.09 & 0.08 & 0.04 & \(-\)0.06 \\ Leptin & 0.06 & 0.06 & 0.07 & 0.06 & 0.06 & 0.01 \\ Adiponectin & \(-\)0.05 & \(-\)0.04 & \(-\)0.07 & \(-\)0.06 & \(-\)0.01 & 0.13 \({}^{*}\) \\ LBP & 0.18 \({}^{*}\) & 0.17 \({}^{*}\) & 0.17 \({}^{*}\) & 0.07 & \(-\)0.12 \({}^{*}\) \\ \hline \multicolumn{5}{c}{**Blood pressure**} \\ \hline Systolic & 0.22 \({}^{*}\) & 0.19 \({}^{*}\) & 0.25 \({}^{*}\) & 0.23 \({}^{*}\) & 0.07 & \(-\)0.21 \({}^{*}\) \\ Diastolic & 0.19 \({}^{*}\) & 0.16 \({}^{*}\) & 0.23 \({}^{*}\) & 0.21 \({}^{*}\) & 0.04 & \(-\)0.16 \({}^{*}\) \\ Mean & 0.21 \({}^{*}\) & 0.18 \({}^{*}\) & 0.25 \({}^{*}\) & 0.23 \({}^{*}\) & 0.06 & \(-\)0.19 \({}^{*}\) \\
**OTU richness** & \(-\)0.28 \({}^{*}\) & \(-\)0.21 \({}^{*}\) & \(-\)0.35 \({}^{*}\) & \(-\)0.33 \({}^{*}\) & \(-\)0.06 & — \\ \hline \multicolumn{5}{c}{**Fecal SCFAs**} \\ \hline Total SCFAs & — & 0.98 \({}^{*}\) & 0.93 \({}^{*}\) & 0.86 \({}^{*}\) & 0.43 \({}^{*}\) & \(-\)0.28 \({}^{*}\) \\ Acetate & 0.98 \({}^{*}\) & — & 0.88 \({}^{*}\) & 0.78 \({}^{*}\) & 0.39 \({}^{*}\) & \(-\)0.21 \({}^{*}\) \\ Propionate & 0.93 \({}^{*}\) & 0.88 \({}^{*}\) & — & 0.86 \({}^{*}\) & 0.41 \({}^{*}\) & \(-\)0.35 \({}^{*}\) \\ Buytrae & 0.86 \({}^{*}\) & 0.78 \({}^{*}\) & 0.86 \({}^{*}\) & — & 0.51 \({}^{*}\) & \(-\)0.33 \({}^{*}\) \\ Isobutyrate & 0.43 \({}^{*}\) & 0.39 \({}^{*}\) & 0.41 \({}^{*}\) & 0.51 \({}^{*}\) & — & \(-\)0.06 \\ \hline \end{tabular}
\end{table} 
Table 2: Multivariable-adjusted Pearson correlations between measures of adiposity, cardiometabolic health, gut microbiota diversity, gut permeability, and fecal SCFA levels. Figure 1: Distribution of gut microbiota diversity according to tertiles (T1: Low, T2: Intermediate, T3: High) of multivariable-adjusted fecal SCFA concentrations: (**a**) Total SCFAs; (**b**) acetate; (**c**) propionate; and (**d**) butyrate. SCFA concentrations were adjusted for age, city of origin, caloric intake, physical activity, and fiber intake. The raw data, average, and 95% confidence intervals are shown for each tertile. To identify the microbial taxa responsible for the differences in overall gut microbiota composition, we fitted multivariable-adjusted quasi-Poisson generalized linear models and found that 70 OTUs were significantly associated with at least one of the fecal SCFAs evaluated in our study (\(q<0.10\)). Of these, 27 showed moderate-to-strong correlations (\(1\,\mathrm{rho}\,|>0.20\); Figure 3). Higher butyrate excretion was positively associated with the abundances of known butyrate-producers, including _Faecalibacterium prausnitzii_, _Roseburia faccis_, and other _Clostridiales_.