title: Intricacies of assessing the human microbiome in epidemiologic studies.
abstract: In the past decade, remarkable relationships have been documented between dysbiosis of the human microbiota and adverse health outcomes. This review seeks to highlight some of the challenges and pitfalls that may be encountered during all stages of microbiota research, from study design and sample collection, to nucleic acid extraction and sequencing, and bioinformatic and statistical analysis.
  
  
  
  Literature focused on human microbiota research was reviewed and summarized.
  
  
  
  Although most studies have focused on surveying the composition of the microbiota, fewer have explored the causal roles of these bacteria, archaea, viruses, and fungi in affecting disease states. Microbiome research is in its relatively early years and many aspects remain challenging, including the complexity and personalized aspects of microbial communities, the influence of exogenous and often confounding factors, the need to apply fundamental principles of ecology and epidemiology, the necessity for new software tools, and the rapidly evolving genomic, technological, and analytical landscapes.
  
  
  
  Incorporating human microbiome research in large epidemiologic studies will soon help us unravel the intricate relationships that we have with our microbial partners and provide interventional opportunities to improve human health.
authors.affiliation: Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore.
authors.forename: Courtney K
authors.initials: CK
authors.lastname: Robinson
authors.affiliation: Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore; Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore. Electronic address: rbrotman@som.umaryland.edu.
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Brotman
authors.affiliation: Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore; Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore. Electronic address: jravel@som.umaryland.edu.
authors.forename: Jacques
authors.initials: J
authors.lastname: Ravel
mesh_terms: D035843:Biomedical Research / Q000379:methods*; D016021:Epidemiologic Studies; D020459:Genes, rRNA / Q000235:genetics* / Q000502:physiology; D006801:Humans; D064307:Microbiota / Q000235:genetics* / Q000502:physiology; D008967:Molecular Biology; D015203:Reproducibility of Results
keywords: 16S ribosomal RNA gene; Metagenomics; Microbiota