title: Serum ghrelin levels and gender-related indices of body composition in prepubertal children: a cross-sectional study.
abstract: BACKGROUND
  A wide variety of functions has been attributed to ghrelin, a peptide hormone secreted in the stomach. The objective of the study was to assess the association of ghrelin concentrations with body composition among Iranian children.
  
  
  METHODS
  In this study, blood samples of 57 boys and 54 girls aged 6-10 were collected to measure ghrelin levels. Fat mass (FM) and fat-free mass (FFM) were examined by body composition analyzer. Actigraph GT3X was administered to assess children's physical activity and sleep. Data were analyzed using linear regression models.
  
  
  RESULTS
  All measured parameters did not differ between genders except for sleep time which was higher and sleep efficacy which was lower in boys compared with girls. None of the FM and FFM indices studied in boys was significantly associated with ghrelin levels. In girls, however, ghrelin concentrations were significantly associated with FM (β = 0.04, P = 0.01), fat mass index (β = 0.07, P = 0.008), and fat-free mass index (β = 0.08, P = 0.04) and near-significantly associated with FFM (β = 0.03, P = 0.09) after adjusting for age, physical activity, sleep, and dietary intake.
  
  
  CONCLUSIONS
  Girls with higher ghrelin levels were more likely to have increased total FM and FFM. Conversely, body composition was not associated with ghrelin levels in boys. Consequently, ghrelin may influence the gender-related differences of body composition during childhood in girls. But, further study is needed to confirm our findings.
authors.affiliation: Department of Community Nutrition, School of Nutritional Sciences and Dietetics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Minoo
authors.initials: M
authors.lastname: Bagheri
authors.forename: Sara
authors.initials: S
authors.lastname: Ansari
authors.forename: Gity
authors.initials: G
authors.lastname: Sotoudeh
authors.forename: Mahmood
authors.initials: M
authors.lastname: Mahmoudi
authors.forename: John R
authors.initials: JR
authors.lastname: Speakman
authors.forename: Kurosh
authors.initials: K
authors.lastname: Djafarian
mesh_terms: D050154:Adiposity; D015415:Biomarkers; D001823:Body Composition; D002648:Child; D002652:Child Behavior; D002657:Child Development; D002664:Child Nutritional Physiological Phenomena; D003430:Cross-Sectional Studies; D005260:Female; D054439:Ghrelin / Q000097:blood*; D006801:Humans; D007492:Iran; D008297:Male; D009043:Motor Activity; D024510:Muscle Development; D012727:Sex Characteristics; D012890:Sleep; D014504:Urban Health
chemical_list: D015415:Biomarkers; C515349:GHRL protein, human; D054439:Ghrelin