title: Obesity is associated with increased 48-h esophageal acid exposure in patients with symptomatic gastroesophageal reflux.
abstract: OBJECTIVE
  Obesity has been associated with gastroesophageal reflux disease (GERD) but the relationship between body mass index (BMI) and esophageal acid exposure remains poorly understood. We hypothesized that overweight (OW) and obese (OB) patients with GER symptoms would have a higher degree of esophageal acid exposure than with normal weight (NW) patients.
  
  
  METHODS
  157 patients separated in groups according to BMI were studied for 48h while off antisecretory medications using ambulatory wireless capsule pH-metry. The pH capsule was appropriately positioned and esophageal pH data were collected. Appropriate univariate and multivariate statistical methods were used.
  
  
  RESULTS
  Groups did not differ in age, but more women were in the NW group. OB patients had a fivefold increase in odds for abnormal total acid exposure compared with NW (OR=5.01; 95% CI 2.94, 12.95). Total acid exposure time (AET) was elevated in OB (8.7%+/-5.1%) compared with NW (5.3%+/-5.2%; P<0.05). AET was highest during awake, upright periods. The DeMeester score was higher in OB (31.7+/-19.2) and OW (26.0+/-16.8) groups compared with the NW (19.8+/-17.6) group (P<0.001). AET increased from day 1 to day 2 in the OB group only.
  
  
  CONCLUSIONS
  This is the first study to report a positive relationship between BMI and esophageal acid exposure time using prolonged, continuous wireless esophageal pH-metry. Abnormal AET was more frequent in OB patients. Variability in AET increased from day 1 to day 2 in the OB group, supporting the use of more prolonged pH studies in subsets of patients.
authors.affiliation: Division of Gastroenterology and Hepatology, Mayo Clinic, Scottsdale, Arizona, USA. crowell.michael@mayo.edu
authors.forename: Michael D
authors.initials: MD
authors.lastname: Crowell
authors.forename: Angela
authors.initials: A
authors.lastname: Bradley
authors.forename: Stephanie
authors.initials: S
authors.lastname: Hansel
authors.forename: Paula
authors.initials: P
authors.lastname: Dionisio
authors.forename: Hack Jae
authors.initials: HJ
authors.lastname: Kim
authors.forename: G Anton
authors.initials: GA
authors.lastname: Decker
authors.forename: John K
authors.initials: JK
authors.lastname: DiBaise
authors.forename: V K
authors.initials: VK
authors.lastname: Sharma
mesh_terms: D016145:Endoscopy, Digestive System; D049630:Esophageal Sphincter, Lower / Q000503:physiopathology; D050782:Esophageal pH Monitoring; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*