title: A systematic review and meta-analysis of the risk of increasing adiposity on Barrett's esophagus.
abstract: OBJECTIVE
  Esophageal adenocarcinoma and its precursor lesion, Barrett's esophagus, are increasing in incidence in western populations. Gastroesophageal reflux disease (GERD) and high body mass index (BMI) are known risk factors, but it is unclear whether BMI mediates its risk on Barrett's esophagus independently. This systematic review and meta-analysis investigated whether increasing BMI is associated with Barrett's esophagus as compared to general population and GERD controls.
  
  
  METHODS
  Search strategies were conducted in MEDLINE (U.S. National Library of Medicine, Bethesda, MD) (1966-2005) and EMBASE (Reed Elsevier PLC, Amsterdam, The Netherlands) (1980-2005). Studies to be included were required to present "current" BMI data for consecutively recruited Barrett's esophagus patients and appropriate comparison arms with a minimum number of 30 subjects in each.
  
  
  RESULTS
  The literature search produced 5,501 hits from which 295 papers were extracted. Only 10 studies met the criteria for inclusion. The Statistics/Data Analysis (STATA) program was used to conduct random effects meta-analyses. Nine studies comparing the BMI of the Barrett's esophagus and GERD groups produced a pooled odds ratio (OR) of 0.99 per kg/m2 (95% confidence interval [CI] 0.97-1.01, I2= 52%), while the pooled estimate of three studies comparing Barrett's esophagus with general population controls was 1.02 per kg/m2 (95% CI 1.01-1.04, I2= 0%).
  
  
  CONCLUSIONS
  Increasing adiposity is only an indirect risk factor of Barrett's esophagus through the precursor lesion of GERD. Hence, BMI status has no predictive value with respect to GERD patients and their risk of progression to Barrett's esophagus.
authors.affiliation: Centre for Epidemiology and Biostatistics, Leeds Institute for Genetics Health and Therapeutics, Faculty of Medicine and Health, University of Leeds, Leeds, England, United Kingdom.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Cook
authors.forename: Darren C
authors.initials: DC
authors.lastname: Greenwood
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Hardie
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Wild
authors.forename: David
authors.initials: D
authors.lastname: Forman
mesh_terms: D000273:Adipose Tissue; D001471:Barrett Esophagus / Q000453:epidemiology* / Q000209:etiology*; D015992:Body Mass Index; D005764:Gastroesophageal Reflux / Q000150:complications*; D006801:Humans; D012307:Risk Factors