title: Associations between body mass, leptin, IGF-I and circulating adrenal androgens in children with obesity and premature adrenarche.
abstract: OBJECTIVE
  To explain why adrenal androgens rise with increasing adiposity during childhood, the role of body mass index (BMI), leptin and IGF-I was studied. We also tested whether these parameters contribute to inducing premature adrenarche (PA).
  
  
  METHODS
  In a cross-sectional study, 26 prepubertal obese children were compared with a group of 26 prepubertal children of normal weight, and 30 children under observation for PA were compared with 30 healthy children, matched for gender, bone age and BMI.
  
  
  METHODS
  Relative contributions of BMI standard deviation scores (SDS) and height SDS, as well as unbound leptin and IGF-I, to the levels of androgens, dehydroepiandrosterone sulfate (DHEAS) and Delta4-androstenedione (AD) were investigated by means of stepwise regression models. Logarithms of all hormones were standardised for age using residuals of a simple regression analysis, labelled by the suffix '(res)'.
  
  
  RESULTS
  In the obese children, height SDS, IGF-I(res,) DHEAS(res) (all P<0.05), leptin(res) (P<0.01), and AD(res) (P=0.07) were higher than in the controls, and covariates were correlated with each other (leptin(res) versus BMI SDS r=0.71, IGF-I(res) versus height SDS r=0.61). In the stepwise regression analysis of control and obese children, BMI SDS explained 26% and leptin(res) explained 12% of the variability of DHEAS(res), but this percentage remained at 26% when both variables were simultaneously introduced into the model. In contrast, IGF-I(res) and BMI SDS alone each accounted for 15% of the variability of AD, and their joint influence accumulated to explain 28% of the variability of AD(res). In PA, neither BMI SDS nor leptin(res) were correlated with the increased androgens.
  
  
  CONCLUSIONS
  Before the onset of gonadal activity in obese and control children, DHEAS levels, to some extent, are explained by BMI and leptin, while IGF-I in addition to BMI in part accounts for AD levels. Enhanced adrenal androgen secretion in children with PA, however, may be explained by parameters other than leptin or BMI.
authors.affiliation: Children's Hospital, Charite Campus Virchow, Humboldt University, Berlin, Germany.
authors.forename: Dagmar
authors.initials: D
authors.lastname: l'Allemand
authors.forename: Stefan
authors.initials: S
authors.lastname: Schmidt
authors.forename: Valentin
authors.initials: V
authors.lastname: Rousson
authors.forename: Georg
authors.initials: G
authors.lastname: Brabant
authors.forename: Theo
authors.initials: T
authors.lastname: Gasser
authors.forename: Annette
authors.initials: A
authors.lastname: Grüters
mesh_terms: D000293:Adolescent; D000302:Adrenal Cortex / Q000378:metabolism*; D000375:Aging / Q000378:metabolism*; D000728:Androgens / Q000097:blood*; D000735:Androstenedione / Q000097:blood; D000886:Anthropometry; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D019314:Dehydroepiandrosterone Sulfate / Q000097:blood; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D020738:Leptin / Q000097:blood*; D008297:Male; D009765:Obesity / Q000097:blood*; D012016:Reference Values; D012044:Regression Analysis
chemical_list: D000728:Androgens; D020738:Leptin; D000735:Androstenedione; D019314:Dehydroepiandrosterone Sulfate; D007334:Insulin-Like Growth Factor I