title: Associations of cardiorespiratory fitness and obesity with risks of impaired fasting glucose and type 2 diabetes in men.
abstract: OBJECTIVE
  The purpose of this study was to examine the associations of cardiorespiratory fitness (hereafter fitness) and various obesity measures with risks of incident impaired fasting glucose (IFG) and type 2 diabetes.
  
  
  METHODS
  This was a prospective cohort study of 14,006 men (7,795 for the analyses of IFG), who did not have an abnormal electrocardiogram or a history of heart attack, stroke, cancer, or diabetes.
  
  
  RESULTS
  Of the men, 3,612 (39,610 person-years) and 477 (101,419 person-years) developed IFG and type 2 diabetes, respectively. Compared with the least fit 20% in multivariate analyses, IFG and type 2 diabetes risks in the most fit 20% were 14 and 52% lower, respectively (both P < 0.001). Men with BMI > or =30.0 kg/m2, waist girth >102.0 cm, or percent body fat > or =25 had 2.7-, 1.9-, and 1.3-fold higher risks for type 2 diabetes, respectively, compared with those for nonobese men (all P < 0.01), and the results for IFG were similar. In the combined analyses, obese unfit (least fit 20%) men had a 5.7-fold higher risk for type 2 diabetes compared with normal-weight fit (most fit 80%) men. We observed similar trends for the joint associations of BMI and fitness with IFG and those of waist girth or percent body fat and fitness with both IFG and type 2 diabetes.
  
  
  CONCLUSIONS
  Low fitness and obesity increased the risks of IFG and type 2 diabetes by approximately similar magnitudes. When considered simultaneously, fitness attenuated but did not eliminate the increased risks of IFG and type 2 diabetes associated with obesity, and the highest risk was found in obese and unfit men.
authors.affiliation: Department of Exercise Science, University of South Carolina, Columbia, South Carolina, USA. lee23@gwm.sc.edu
authors.forename: Duck-Chul
authors.initials: DC
authors.lastname: Lee
authors.forename: Xuemei
authors.initials: X
authors.lastname: Sui
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Church
authors.forename: I-Min
authors.initials: IM
authors.lastname: Lee
authors.forename: Steven N
authors.initials: SN
authors.lastname: Blair
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology*; D004562:Electrocardiography; D005080:Exercise Test; D018149:Glucose Intolerance / Q000453:epidemiology*; D006321:Heart / Q000502:physiology / Q000503:physiopathology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009765:Obesity / Q000150:complications*; D010809:Physical Fitness; D011446:Prospective Studies; D012143:Respiratory Physiological Phenomena; D012137:Respiratory System / Q000503:physiopathology; D012307:Risk Factors; D013781:Texas; D055815:Young Adult