A systematic review and meta-analysis of the risk of increasing adiposity on Barrett's esophagus.
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. 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. 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%). 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.