title: Beta-diversity metrics of the upper digestive tract microbiome are associated with body mass index.
abstract: OBJECTIVE
  Studies of the fecal microbiome have implicated the gut microbiota in obesity, but few studies have examined the microbial diversity at other sites. The association between obesity and the upper gastrointestinal (UGI) microbial diversity was explored.
  
  
  METHODS
  The UGI microbiome of 659 healthy Chinese adults with a measured body mass index (BMI) range of 15.0 to 35.7 was characterized using the 16S rRNA gene DNA microarray (HOMIM).
  
  
  RESULTS
  In multivariate-adjusted models, alpha diversity was not associated with BMI. However, beta diversity, assessed by principal coordinate vectors generated from an unweighted UniFrac distance matrix of pairwise comparisons, was associated with BMI (third and fourth vectors, P = 0.01 and P = 0.03, respectively). Moreover, beta diversity, assessed by cluster membership (three clusters), was also associated with BMI; individuals in the first cluster [median BMI 22.35, odds ratio (OR) = 0.48, 95% confidence interval (CI) = 0.05-4.34] and second cluster [median BMI 22.55, OR = 0.26, 95% CI = 0.09-0.75] were significantly less likely to be obese (BMI ≥ 27.5) than those in the third cluster (median BMI 23.59).
  
  
  CONCLUSIONS
  A beta-diversity metric of the UGI microbiome is associated with a four fold difference in obesity risk in this Asian population. Future studies should address whether the UGI microbiome plays a causal role in obesity.
authors.affiliation: Division of Cancer Epidemiology & Genetics, National Cancer Institute, Bethesda, Maryland, USA.
authors.forename: Shih-Wen
authors.initials: SW
authors.lastname: Lin
authors.forename: Neal D
authors.initials: ND
authors.lastname: Freedman
authors.forename: Jianxin
authors.initials: J
authors.lastname: Shi
authors.forename: Mitchell H
authors.initials: MH
authors.lastname: Gail
authors.forename: Emily
authors.initials: E
authors.lastname: Vogtmann
authors.forename: Guoqin
authors.initials: G
authors.lastname: Yu
authors.forename: Vanja
authors.initials: V
authors.lastname: Klepac-Ceraj
authors.forename: Bruce J
authors.initials: BJ
authors.lastname: Paster
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Dye
authors.forename: Guo-Qing
authors.initials: GQ
authors.lastname: Wang
authors.forename: Wen-Qiang
authors.initials: WQ
authors.lastname: Wei
authors.forename: Jin-Hu
authors.initials: JH
authors.lastname: Fan
authors.forename: You-Lin
authors.initials: YL
authors.lastname: Qiao
authors.forename: Sanford M
authors.initials: SM
authors.lastname: Dawsey
authors.forename: Christian C
authors.initials: CC
authors.lastname: Abnet
mesh_terms: D000328:Adult; D015992:Body Mass Index; D002681:China; D004269:DNA, Bacterial / Q000032:analysis*; D005243:Feces / Q000382:microbiology*; D005260:Female; D006801:Humans; D008297:Male; D064307:Microbiota; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology / Q000382:microbiology*; D016017:Odds Ratio; D012336:RNA, Ribosomal, 16S / Q000032:analysis*
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S