title: Relationships of body composition and liver fat content with insulin resistance in obesity-matched adolescents and adults.
abstract: OBJECTIVE
  While in adults not total body- or visceral fat mass, but liver fat content was found to independently determine insulin resistance, it is unclear whether these relationships are already present in obese adolescents.
  
  
  METHODS
  Thirty-nine overweight/obese adolescents were matched for sex and BMI with 39 adults. To compare the age- and sex-specific BMI values of adolescents and adults, the percentile value of each adolescent was projected to the age of 18. Body fat depots were quantified by whole-body magnetic resonance (MR) imaging. Liver fat content was measured with (1)H-MR spectroscopy. Insulin resistance was estimated from the homeostasis model assessment of insulin resistance (HOMA-IR).
  
  
  RESULTS
  Compared to overweight and obese adults, adolescents had higher HOMA-IR (P < 0.001) and lower lean body mass (P = 0.002). Furthermore, they had higher total body- (P = 0.02), but lower visceral- (P < 0.001) fat mass, while liver fat content was not significantly different between the groups (P = 0.16). In both groups liver fat content (both P ≤ 0.007), but not total body- or visceral fat mass (all P ≥ 0.64) was an independent predictor of insulin resistance.
  
  
  CONCLUSIONS
  Having lower visceral fat mass, overweight and obese adolescents are more insulin resistant than sex- and BMI-matched adults. Liver fat content, but not total body- or visceral fat mass, is an independent determinant of insulin resistance in adolescents.
authors.affiliation: Department of Internal Medicine Division of Endocrinology and Diabetology Vascular Medicine Nephrology and Clinical Chemistry, University Hospital Tübingen, Tübingen, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen (IDM), Tübingen, Germany.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Linder
authors.forename: Fabian
authors.initials: F
authors.lastname: Springer
authors.forename: Jürgen
authors.initials: J
authors.lastname: Machann
authors.forename: Fritz
authors.initials: F
authors.lastname: Schick
authors.forename: Andreas
authors.initials: A
authors.lastname: Fritsche
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Häring
authors.forename: Gunnar
authors.initials: G
authors.lastname: Blumenstock
authors.forename: Michael B
authors.initials: MB
authors.lastname: Ranke
authors.forename: Norbert
authors.initials: N
authors.lastname: Stefan
authors.forename: Gerhard
authors.initials: G
authors.lastname: Binder
authors.forename: Stefan
authors.initials: S
authors.lastname: Ehehalt
mesh_terms: D050154:Adiposity; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D015992:Body Mass Index; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D050152:Intra-Abdominal Fat; D016014:Linear Models; D008099:Liver / Q000737:chemistry*; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology*
keywords: body composition; insulin resistance; liver fat