title: Positive associations between serum levels of IGF-I and subcutaneous fat depots in young men. The Odense Androgen Study.
abstract: BACKGROUND
  Serum levels of IGF-I are of growing interest due to the associations with morbidity and mortality. Despite markedly suppressed GH secretion, total IGF-I levels are often within normal range in obese adults.
  
  
  OBJECTIVE
  To study associations between IGF-I and estimated muscle mass in the Odense Androgen Study population and secondly to investigate associations between serum IGF-I and regional fat depots.
  
  
  METHODS
  The Odense Androgen Study is a population-based, cross-sectional study of 776 randomly selected men aged 20-29 years. Regional lean and fat mass were measured by dual-energy X-ray absorptiometry, whereas regional muscle and fat areas were assessed by magnetic resonance imaging.
  
  
  RESULTS
  Age-adjusted IGF-I levels correlated significantly with different estimates of muscle mass (r-values between 0.15 and 0.19; p<0.001). Using multiple linear regression, serum IGF-I correlated positively with subcutaneous adipose tissue on the abdomen (SAT) after controlling for visceral adipose tissue (VAT) in the whole group and in the subgroup of men with normal waist circumference (r-values between 0.13 and 0.15; p<0.03). In addition, IGF-I correlated positively with subcutaneous thigh fat area (TFA) after controlling for intramyocellular lipid (imcl) r=0.18; p<0.004) and IGF-I correlated negatively with TFAimcl in the whole group and in the subgroup of men with normal waist circumference.
  
  
  CONCLUSIONS
  SAT and subcutaneous TFAs were positively associated with IGF-I in regression analyses. Conversely, imcl of the thigh was inversely associated with IGF-I levels. These findings emphasize the differential associations between IGF-I and regional fat deposits. Future studies may provide further insight regarding the interplay between circulating IGF-I levels and regional muscle and fat mass.
authors.affiliation: Department of Endocrinology, Odense University Hospital, 5000 Odense C, Denmark. Marianne.Andersen@ouh.regionsyddanmark.dk
authors.forename: M
authors.initials: M
authors.lastname: Andersen
authors.forename: K
authors.initials: K
authors.lastname: Brixen
authors.forename: C
authors.initials: C
authors.lastname: Hagen
authors.forename: J
authors.initials: J
authors.lastname: Frystyk
authors.forename: T L
authors.initials: TL
authors.lastname: Nielsen
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000728:Androgens / Q000378:metabolism; D001823:Body Composition; D003430:Cross-Sectional Studies; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis* / Q000378:metabolism; D050152:Intra-Abdominal Fat / Q000737:chemistry / Q000000981:diagnostic imaging; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D050151:Subcutaneous Fat / Q000737:chemistry* / Q000000981:diagnostic imaging; D055105:Waist Circumference; D055815:Young Adult
chemical_list: D000728:Androgens; D007334:Insulin-Like Growth Factor I