title: Cardiorespiratory fitness and visceral fat are key determinants of serum fibroblast growth factor 21 concentration in Japanese men.
abstract: BACKGROUND
  Fibroblast growth factor-21 (FGF21) is an important metabolic regulator suggested to improve glucose metabolism and prevent dyslipidemia. An FGF21-resistant state that increases circulating FGF21 has been reported in obese patients. Although regular exercise prevents metabolic disease, the relationship of the fitness level to serum FGF21 level and body fat distribution in humans remains poorly understood.
  
  
  OBJECTIVE
  The objective of the study was to determine the relationship among the serum FGF21 concentration, cardiorespiratory fitness (CRF) level, and visceral fat area (VFA).
  
  
  METHODS
  Serum FGF21 was measured by an ELISA in 166 middle-aged and elderly Japanese men (aged 30-79 y) and 25 untrained and 21 endurance-trained young men (aged 19-29 y). CRF was assessed by measuring the peak oxygen uptake (VO2peak) and VFA by magnetic resonance imaging.
  
  
  RESULTS
  In the middle-aged and elderly subjects, the serum FGF21 level correlated with the VO2peak (r = -0.355, P < .001) and VFA (r = 0.487, P < .001). Stepwise multiple regression analysis showed VFA to be most strongly associated with the serum FGF21 level (β = .360, P < .001), and VO2peak was also an independent predictor of the serum FGF21 level (β = -.174, P = .019). Furthermore, the proportion of subjects with an FGF21 level below the limit of detection was significantly higher among the endurance-trained than among the untrained young men (71.4% vs 24.0%, P = .001), and the VO2peak and VFA were independently associated with an undetectable FGF21 level (P < .05).
  
  
  CONCLUSIONS
  CRF and VFA are key determinants of the circulating FGF21 concentration.
authors.affiliation: Graduate School of Sport Sciences (H.T., K.T., X.S., R.I.) and Faculty of Sport Sciences (Z.-B.C., S.O., S.S., M.H.), Waseda University, and Institute of Advanced Active Aging Research (S.S., M.H.), Tokorozawa 359-1192, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Taniguchi
authors.forename: Kumpei
authors.initials: K
authors.lastname: Tanisawa
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Sun
authors.forename: Zhen-Bo
authors.initials: ZB
authors.lastname: Cao
authors.forename: Satomi
authors.initials: S
authors.lastname: Oshima
authors.forename: Ryuken
authors.initials: R
authors.lastname: Ise
authors.forename: Shizuo
authors.initials: S
authors.lastname: Sakamoto
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Higuchi
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D044466:Asian People; D001786:Blood Glucose / Q000378:metabolism; D005080:Exercise Test; D005346:Fibroblast Growth Factors / Q000097:blood*; D006801:Humans; D007328:Insulin / Q000097:blood; D050152:Intra-Abdominal Fat / Q000378:metabolism*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D016017:Odds Ratio; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology*; D012307:Risk Factors; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D007328:Insulin; C414620:fibroblast growth factor 21; D005346:Fibroblast Growth Factors