Visceral adipose tissue is an independent correlate of glucose disposal inolder obese postmenopausal women

Older obese postmenopausal women have an increased risk for type 2 diabetes and cardiovascular disease. Increased abdominal obesity may contribute to these comorbidities. There is considerable controversy, however, regarding the effects of visceral adipose tissue as a singular predictor of insulin r esistance compared to the other constituents of adiposity. To address this issue, we examined the independent association of regional adiposity and to tal fat mass with glucose disposal in obese older postmenopausal women. A s econdary objective examined the association between glucose disposal with m arkers of skeletal muscle fat content (muscle attenuation) and physical act ivity levels. We studied 44 healthy obese postmenopausal women between 50 and 71 yr of ag e (mean +/- so, 56.5 +/- 5.3 yr). The rate of glucose disposal was measured using the euglycemic/hyperinsulinemic clamp technique. Visceral and sc adi pose tissue areas and midthigh muscle attenuation were measured from comput ed tomography. Fat mass and lean body mass were estimated from dual energy x-ray absorptiometry. Peak VO2 was measured from a treadmill test to voliti onal fatigue. Physical activity energy expenditure was measured from indire ct calorimetry and doubly labeled water. Pearson correlations indicated that glucose disposal was inversely related to visceral adipose tissue area (r = -0.40; P < 0.01), but not to sc adipos e tissue area (r = 0.17), total fat mass (r = 0.05), midthigh muscle attenu ation (r =0.01), peak VO2 (r = -0.22), or physical activity energy expendit ure (r = -0.01). The significant association persisted after adjusting visc eral adipose tissue for fat mass and abdominal sc adipose tissue levels (r = -0.45; P < 0.005; in both cases). Additional analyses matched two groups of women for fat mass, but with different visceral adipose tissue levels. R esults showed that obese women with high visceral adipose tissue levels (28 3 +/- 59 vs. 137 +/- 24 cm(2); P < 0.0001) had a lower glucose disposal per kg lean body mass compared to those with low visceral adipose tissue level s (0.44 +/- 0.14 vs. 0.66 +/- 0.28 mmol/kg min; P < 0.05). Visceral adipose tissue is an important and independent predictor of glucos e disposal, whereas markers of skeletal muscle fat content or physical acti vity exhibit little association in obese postmenopausal women.