title: Meta-analyses of human gut microbes associated with obesity and IBD.
abstract: Recent studies have linked human gut microbes to obesity and inflammatory bowel disease, but consistent signals have been difficult to identify. Here we test for indicator taxa and general features of the microbiota that are generally consistent across studies of obesity and of IBD, focusing on studies involving high-throughput sequencing of the 16S rRNA gene (which we could process using a common computational pipeline). We find that IBD has a consistent signature across studies and allows high classification accuracy of IBD from non-IBD subjects, but that although subjects can be classified as lean or obese within each individual study with statistically significant accuracy, consistent with the ability of the microbiota to experimentally transfer this phenotype, signatures of obesity are not consistent between studies even when the data are analyzed with consistent methods. The results suggest that correlations between microbes and clinical conditions with different effect sizes (e.g. the large effect size of IBD versus the small effect size of obesity) may require different cohort selection and analysis strategies.
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA.
authors.forename: William A
authors.initials: WA
authors.lastname: Walters
authors.affiliation: BioFrontiers Institute, University of Colorado, Boulder, CO 80309, USA.
authors.forename: Zech
authors.initials: Z
authors.lastname: Xu
authors.affiliation: BioFrontiers Institute, University of Colorado, Boulder, CO 80309, USA; Department of Chemistry & Biochemistry, University of Colorado, Boulder, CO 80309, USA; Howard Hughes Medical Institute, Boulder, CO 80309, USA. Electronic address: rob@colorado.edu.
authors.forename: Rob
authors.initials: R
authors.lastname: Knight
mesh_terms: D000818:Animals; D005243:Feces / Q000382:microbiology; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000382:microbiology*; D009765:Obesity / Q000382:microbiology*; D017423:Sequence Analysis, RNA
keywords: Gut microbiota; Metaanalysis