THE ROLE OF OBESITY AND CARDIOVASCULAR FITNESS LN THE IMPAIRED GLUCOSE-TOLERANCE OF AGING

The prevalence of impaired glucose tolerance (IGT) increases with agin g. Although some data suggest that age is independently associated wit h IGT, other studies suggest that age-associated changes in body compo sition and reduced cardiovascular fitness are responsible for the deve lopment of IGT. We, therefore, examined the relationship of age, total and regional adiposity, and level of fitness (VO(2)max) to the presen ce of IGT in 155 healthy, nondiabetic, nonsmoking, older community dwe lling men. Sixty-two of 155 men (40%) had IGT, while 93 men (60%) had normal glucose tolerance (WHO criteria). The subjects with IGT were of similar age (61.0 +/- 1.0 vs. 59.0 +/- 0.7 years, p = 0.49) and had t he same maximal aerobic capacity, (VO(2)max) (42 0 +/- 1.0 vs. 44.0 +/ - 0.8 mL/kg ffm/min, p = 0.42), but had a higher waist to hip ratio (W HR) (0.98 +/- 0.01 vs. 0.96 +/- 0.01, p = 0.005) and percent body fat (30.0 +/- 0.4 vs. 26.0 +/- 0.6, p = 0.004) than the men with normal gl ucose tolerance. In univariate analysis, the 2-h glucose level correla ted positively with percent body fat (r = 0.30, p = 0.0002), WHR (0.24 , p = 0.002), and age (r = 0.17, p = 0.03) and negatively with VO(2)ma x (r = -0.23, p = 0.005). In both multiple logistic and linear regress ion analyses, percent body fat was the only independent predictor of I GT (p = 0.002). These results suggest that the age-associated increase in total adiposity is a major contributor to the development of IGT i n middle-aged and older men. Thus, lifestyle modifications that reduce body fat should reduce the risk for IGT and the development of nonins ulin-dependent diabetes mellitus in the elderly.