Associations between fecal bacterial populations and markers of host cholesterol metabolism. Four-parameter sigmoidal inhibitory regressions between fecal abundance of Coriobacteriaceae (A, B, and C), OTU1 (D, E, and F), and OTU13 (G, H, and I) with whole-body cholesterol synthesis (A, D, and G), fecal biliary cholesterol excretion (B, E, and H), and fecal cholesterol excretion (C, F, and I). BW, body weight.