title: Interrelationships among changes in leptin, insulin, cortisol and growth hormone and weight status in youth.
abstract: OBJECTIVE
  While acute alterations in leptin, insulin, cortisol and growth hormone (GH) levels have been reported in children following weight change interventions, little is known about natural hormonal changes as children grow and how these changes are affected by unprovoked weight status changes. The purpose of this investigation was to compare changes in leptin, insulin, cortisol and GH levels in youth who maintained their weight status vs. those who moved from normal weight to overweight or vice versa.
  
  
  METHODS
  Data were collected from 120 youth at baseline (9.8±1.0 years) and two years later. Participants were selected from a larger cohort to represent all scenarios of weight status: normal weight [>5(th) and <85(th) body mass index (BMI) percentile] at both time points (NN), overweight (≥85(th) BMI percentile) at both time points (OO), normal weight status who changed to overweight (NO) and overweight status which changed to normal weight (ON). Hormonal concentrations were measured from fasting venous blood.
  
  
  RESULTS
  In youth who changed their weight status, there were significant associations (p<0.05) between changes in BMI percentile and changes in leptin, insulin and cortisol (partial R(2)=0.35, 0.13 and 0.11, respectively), after accounting for race, sex and changes in pubertal status and aerobic power. Our key findings were that youth who became overweight (NO) showed greater changes for leptin (+205% vs. -21%) and cortisol (-33% vs. +13%), p<0.05 than those who reverted from overweight to normal weight (ON).
  
  
  CONCLUSIONS
  Natural changes in weight status in youth show a relationship with changes in leptin, insulin and cortisol levels and the hormonal changes appear to be more sensitive to increases, rather than reductions, in weight status.
authors: University of North Carolina at Chapel Hill, Department of Exercise and Sport Science, Chapel Hill, NC, USA. kristin.ondrak@gmail.com
authors: Kristin S
authors: KS
authors: Ondrak
authors: Robert G
authors: RG
authors: McMurray
authors: Anthony C
authors: AC
authors: Hackney
authors: Joanne S
authors: JS
authors: Harrell
mesh_terms: D001835:Body Weight / Q000502:physiology*; D002648:Child; D005260:Female; D019382:Human Growth Hormone / Q000097:blood*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007328:Insulin / Q000097:blood*; D020738:Leptin / Q000097:blood*; D008297:Male
chemical_list: D007328:Insulin; D020738:Leptin; D019382:Human Growth Hormone; D006854:Hydrocortisone