title: Regional gastrointestinal transit and pH studied in 215 healthy volunteers using the wireless motility capsule: influence of age, gender, study country and testing protocol.
abstract: BACKGROUND
  The wireless motility capsule (WMC) offers the ability to investigate luminal gastrointestinal (GI) physiology in a minimally invasive manner.
  
  
  OBJECTIVE
  To investigate the effect of testing protocol, gender, age and study country on regional GI transit times and associated pH values using the WMC.
  
  
  METHODS
  Regional GI transit times and pH values were determined in 215 healthy volunteers from USA and Sweden studied using the WMC over a 6.5-year period. The effects of test protocol, gender, age and study country were examined.
  
  
  RESULTS
  For GI transit times, testing protocol was associated with differences in gastric emptying time (GET; shorter with protocol 2 (motility capsule ingested immediately after meal) vs. protocol 1 (motility capsule immediately before): median difference: 52 min, P = 0.0063) and colonic transit time (CTT; longer with protocol 2: median 140 min, P = 0.0189), but had no overall effect on whole gut transit time. Females had longer GET (by median 17 min, P = 0.0307), and also longer CTT by (104 min, P = 0.0285) and whole gut transit time by (263 min, P = 0.0077). Increasing age was associated with shorter small bowel transit time (P = 0.002), and study country also influenced small bowel and CTTs. Whole gut and CTTs showed clustering of data at values separated by 24 h, suggesting that describing these measures as continuous variables is invalid. Testing protocol, gender and study country also significantly influenced pH values.
  
  
  CONCLUSIONS
  Regional GI transit times and pH values, delineated using the wireless motility capsule (WMC), vary based on testing protocol, gender, age and country. Standardisation of testing is crucial for cross-referencing in clinical practice and future research.
authors.affiliation: Neurogastroenterology Group (GI Physiology Unit), Blizard Institute of Cell and Molecular Science, Queen Mary University, London, UK.
authors.forename: Y T
authors.initials: YT
authors.lastname: Wang
authors.affiliation: Neurogastroenterology Group (GI Physiology Unit), Blizard Institute of Cell and Molecular Science, Queen Mary University, London, UK.
authors.forename: S D
authors.initials: SD
authors.lastname: Mohammed
authors.affiliation: Neurogastroenterology Group (GI Physiology Unit), Blizard Institute of Cell and Molecular Science, Queen Mary University, London, UK.|University Hospitals of North Midlands, Royal Stoke University Hospital, Stoke on Trent, UK.
authors.forename: A D
authors.initials: AD
authors.lastname: Farmer
authors.affiliation: Biostatistics Unit, Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK.
authors.forename: D
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Gastroenterology, University College London Hospital, London, UK.
authors.forename: N
authors.initials: N
authors.lastname: Zarate
authors.affiliation: The Functional Gut Clinic, London, UK.
authors.forename: A R
authors.initials: AR
authors.lastname: Hobson
authors.affiliation: Department of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden.
authors.forename: P M
authors.initials: PM
authors.lastname: Hellström
authors.affiliation: Medtronic, Minneapolis, MN, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Semler
authors.affiliation: Gastroenterology Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: B
authors.initials: B
authors.lastname: Kuo
authors.affiliation: Section of Gastroenterology and Hepatology, Georgia Health Sciences University, Medical College of Georgia, Augusta, GA, USA.
authors.forename: S S
authors.initials: SS
authors.lastname: Rao
authors.affiliation: Division of Gastroenterology, University of Michigan Health System, Ann Arbor, MI, USA.
authors.forename: W L
authors.initials: WL
authors.lastname: Hasler
authors.affiliation: Clinical Enteric Neuroscience Translational and Epidemiological Research (CENTER), Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA.
authors.forename: M
authors.initials: M
authors.lastname: Camilleri
authors.affiliation: Neurogastroenterology Group (GI Physiology Unit), Blizard Institute of Cell and Molecular Science, Queen Mary University, London, UK.
authors.forename: S M
authors.initials: SM
authors.lastname: Scott
mesh_terms: D000328:Adult; D000367:Age Factors; D053704:Capsule Endoscopy / Q000379:methods*; D002985:Clinical Protocols; D005260:Female; D005746:Gastric Emptying / Q000502:physiology*; D005772:Gastrointestinal Transit / Q000502:physiology*; D064368:Healthy Volunteers; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D013548:Sweden; D013997:Time Factors; D014481:United States