title: The role of leptin and other hormones related to bone metabolism and appetite regulation as determinants of gain in body fat and fat-free mass in 8-11-year-old children.
abstract: BACKGROUND
  Regulation of body composition during childhood is complex. Numerous hormones are potentially involved. Leptin has been proposed to restrain weight gain, but results are inconsistent.
  
  
  OBJECTIVE
  We examined whether baseline fasting levels of ghrelin, adiponectin, leptin, insulin, IGF-I, osteocalcin, and intact parathyroid hormone (iPTH) were associated with body composition cross sectionally and longitudinally in 633 8-11-year-olds.
  
  
  METHODS
  Data on hormones and body composition by dual-energy x-ray absorptiometry from the OPUS School Meal Study were used. We looked at baseline hormones as predictors of baseline fat mass index (FMI) or fat-free mass index (FFMI), and also subsequent changes (3 and 6 months) in FMI or FFMI using models with hormones individually or combined.
  
  
  RESULTS
  Cross-sectionally, baseline leptin was positively associated with FMI in girls (0.211 kg/m(2) pr. μg/mL; 97.5% confidence interval [CI],0.186-0.236; P < .001) and boys (0.231 kg/m(2) pr. μg/mL; 97.5% CI, 0.200-0.261; P < .001). IGF-I in both sexes and iPTH in boys were positively associated with FMI. An inverse association between adiponectin and FFMI in boys and a positive association between IGF-I and FFMI were found in girls. In longitudinal models, baseline leptin was inversely associated with subsequent changes in FMI (-0.018 kg/m(2) pr. μg/mL; 97.5% CI, -0.034 - -0.002; P = .028) and FFMI (-0.014 kg/m(2) pr. μg/mL; 97.5% CI, -0.024 - -0.003; P = .006) in girls.
  
  
  CONCLUSIONS
  Cross-sectional findings support that leptin is produced in proportion to body fat mass, but the longitudinal observations support that leptin inhibits gains in FMI and FFMI in girls, a finding that may reflect preserved leptin sensitivity in this predominantly normal weight population.
authors.affiliation: Department of Nutrition, Exercise and Sports, Faculty of Science (S.-M.D., C.R., A.L., C.T.P., R.A.P., L.B.S., A.A., C.M., K.F.M.), University of Copenhagen, 1958 Frederiksberg C Denmark; and MRC Epidemiology Unit (K.K.O.), University of Cambridge School of Clinical Medicine, CB2 0SL Cambridge, United Kingdom.
authors.forename: Stine-Mathilde
authors.initials: SM
authors.lastname: Dalskov
authors.forename: Christian
authors.initials: C
authors.lastname: Ritz
authors.forename: Anni
authors.initials: A
authors.lastname: Larnkjær
authors.forename: Camilla T
authors.initials: CT
authors.lastname: Damsgaard
authors.forename: Rikke A
authors.initials: RA
authors.lastname: Petersen
authors.forename: Louise B
authors.initials: LB
authors.lastname: Sørensen
authors.forename: Ken K
authors.initials: KK
authors.lastname: Ong
authors.forename: Arne
authors.initials: A
authors.lastname: Astrup
authors.forename: Christian
authors.initials: C
authors.lastname: Mølgaard
authors.forename: Kim F
authors.initials: KF
authors.lastname: Michaelsen
mesh_terms: D000273:Adipose Tissue / Q000254:growth & development; D001069:Appetite Regulation / Q000502:physiology*; D001823:Body Composition / Q000502:physiology; D001842:Bone and Bones / Q000378:metabolism*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006728:Hormones / Q000097:blood / Q000502:physiology*; D006801:Humans; D020738:Leptin / Q000097:blood / Q000502:physiology*; D008137:Longitudinal Studies; D008297:Male; D010012:Osteogenesis / Q000502:physiology; D015430:Weight Gain / Q000502:physiology*
chemical_list: D006728:Hormones; D020738:Leptin