title: Changes in gut hormones and leptin in military personnel during operational deployment in Afghanistan.
abstract: OBJECTIVE
  Understanding the mechanisms that drive weight loss in a lean population may elucidate systems that regulate normal energy homeostasis. This prospective study of British military volunteers investigated the effects of a 6-month deployment to Afghanistan on energy balance and circulating concentrations of specific appetite-regulating hormones.
  
  
  METHODS
  Measurements were obtained twice in the UK (during the Pre-deployment period) and once in Afghanistan, at Mid-deployment. Body mass, body composition, food intake, and appetite-regulatory hormones (leptin, active and total ghrelin, PYY, PP, GLP-1) were measured.
  
  
  RESULTS
  Repeated measures analysis of 105 volunteers showed body mass decreased by 4.9% ± 3.7% (P < 0.0001) during the first half of the deployment. Leptin concentrations were significantly correlated with percentage body fat at each time point. The reduction in percentage body fat between Pre-deployment and Mid-deployment was 8.6%, with a corresponding 48% decrease in mean circulating leptin. Pre-deployment leptin and total and active ghrelin levels correlated with subsequent change in body mass; however. no changes were observed in the anorectic gut hormones GLP-1, PP, or PYY.
  
  
  CONCLUSIONS
  These data suggest that changes in appetite-regulating hormones in front line military personnel occur in response to, but do not drive, reductions in body mass.
authors.affiliation: Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK; Section of Investigative Medicine, Imperial College London, London, UK.
authors.forename: Neil E
authors.initials: NE
authors.lastname: Hill
authors.forename: Joanne L
authors.initials: JL
authors.lastname: Fallowfield
authors.forename: Simon K
authors.initials: SK
authors.lastname: Delves
authors.forename: Christian
authors.initials: C
authors.lastname: Ardley
authors.forename: Michael
authors.initials: M
authors.lastname: Stacey
authors.forename: Mohammad
authors.initials: M
authors.lastname: Ghatei
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Bloom
authors.forename: Gary
authors.initials: G
authors.lastname: Frost
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Brett
authors.forename: Duncan R
authors.initials: DR
authors.lastname: Wilson
authors.forename: Kevin G
authors.initials: KG
authors.lastname: Murphy
mesh_terms: D000328:Adult; D055826:Afghan Campaign 2001-; D000346:Afghanistan; D001823:Body Composition; D004435:Eating; D004734:Energy Metabolism; D005768:Gastrointestinal Hormones / Q000097:blood*; D054439:Ghrelin / Q000097:blood; D052216:Glucagon-Like Peptide 1 / Q000097:blood; D006801:Humans; D020738:Leptin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D008889:Military Personnel; D019894:Peptide YY / Q000097:blood; D011446:Prospective Studies; D015431:Weight Loss; D055815:Young Adult
chemical_list: D005768:Gastrointestinal Hormones; D054439:Ghrelin; D020738:Leptin; D019894:Peptide YY; D052216:Glucagon-Like Peptide 1