Alonso A, et al. - In an independent sample of 2,003 white and black ARIC participants, researchers sought to replicate their previous findings demonstrating the associations of 2 circulating secondary bile acids (glycocholenate and glycolithocolate sulfate) with atrial fibrillation (AF) risk among 1,919 blacks in the ARIC cohort. In addition, they performed a new metabolomic analysis in the combined sample of 3,922 participants, followed between 1987 and 2013. Over a mean follow-up of 20 years, AF developed in 608 participants. In the replication and combined samples, the association between glycocholenate sulfate with AF remained evident. No relation of glycolithocolate sulfate to AF risk could be demonstrated in the replication sample. In the combined cohort, an analysis of 245 metabolites yielded 3 additional metabolites involved in nucleoside and polyamine metabolism as markers of AF risk: pseudouridine, uridine and acisoga.