Determinants of bile acids.

632 Background: Several epidemiological studies have demonstrated an association between bile acids (BA) and colorectal cancer. Despite this evidence, there are limited studies that examine the determinants of bile acids in humans. We conducted a secondary, cross-sectional analysis on 735 adenoma formers from a phase III adenoma prevention trial of ursodeoxycholic acid (URSO) who provided a fecal sample at their baseline visit. Methods: Fecal measures of primary bile acids cholic acid (CA) and chenodoxycholic acid (CDCA), as well as secondary bile acids, deoxycholic acid (DCA), lithocholic (LCA) were the outcome variables of interest. Dietary, non-dietary, medication use, genetic variation in the CYP7A1 gene (as single nucleotide polymorphisms (SNPs) and haplotypes), and physical activity, and characteristics of baseline adenoma were evaluated as correlates of fecal BAs. We used maximum likelihood methods to incorporate left-censoring in the BAs that had concentrations below the detection limit (BDL). The...