title: Adiposity, aerobic fitness, muscle fitness, and markers of inflammation in children.
abstract: OBJECTIVE
  The purpose of this study was to describe levels of inflammation markers in Norwegian children and to examine the associations of adiposity, aerobic fitness, and muscle fitness with markers of inflammation.
  
  
  METHODS
  In 2005-2006, 1467 nine-year-olds were randomly selected from all regions in Norway. The participation rate was 89%. The inflammatory markers evaluated included C-reactive protein (CRP), leptin, adiponectin, plasminogen activator inhibitor-1, tumor necrosis factor-α, hepatocyte growth factor, resistin, and interleukin-6. We assessed muscular strength by measuring explosive, isometric, and endurance strength. Aerobic fitness was measured directly during a maximal cycle ergometer test. Adiposity was expressed as waist circumference (WC).
  
  
  RESULTS
  The girls had significantly higher levels of CRP, leptin, adiponectin, and resistin and lower levels of tumor necrosis factor-α compared with the boys. We observed a graded association of CRP and leptin levels across quintiles of WC, aerobic fitness, and muscle fitness (P ≤ 0.001 for all participants). The regression analyses revealed that WC, aerobic fitness, and muscle fitness were independently associated with the CRP (WC β = 0.158, P < 0.001; aerobic fitness β = -0.190, P < 0.001; muscle fitness β = -0.122, P < 0.002) after adjustments for sex, age, Tanner pubertal stage, and the other independent variables. The same pattern was observed for leptin levels (WC β = 0.406, P < 0.001; aerobic fitness β = -0.298, P < 0.001; muscle fitness β = -0.064, P < 0.036).
  
  
  CONCLUSIONS
  These data represent a reference material with respect to inflammatory markers. Our results show that adiposity, aerobic fitness, and muscle fitness were independently associated with the CRP and leptin levels.
authors.affiliation: Department of Sports, Faculty of Teacher Education and Sports, Sogn og Fjordane University College, Sogndal, Norway. jostsj@hisf.no
authors.forename: Jostein
authors.initials: J
authors.lastname: Steene-Johannessen
authors.forename: Elin
authors.initials: E
authors.lastname: Kolle
authors.forename: Lars Bo
authors.initials: LB
authors.lastname: Andersen
authors.forename: Sigmund A
authors.initials: SA
authors.lastname: Anderssen
mesh_terms: D050154:Adiposity / Q000502:physiology*; D015415:Biomarkers / Q000097:blood; D002648:Child; D005080:Exercise Test; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000175:diagnosis*; D018836:Inflammation Mediators / Q000097:blood*; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D009664:Norway; D010809:Physical Fitness / Q000502:physiology*; D012044:Regression Analysis; D017678:Sex Distribution
chemical_list: D015415:Biomarkers; D018836:Inflammation Mediators