Associations of cardiorespiratory fitness and obesity with risks of impaired fasting glucose and type 2 diabetes in men.
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.
Lee
Duck-Chul
DC
Department of Exercise Science, University of South Carolina, Columbia, South Carolina, USA. lee23@gwm.sc.edu
Sui
Xuemei
X
Church
Timothy S
TS
Lee
I-Min
IM
Blair
Steven N
SN
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