Comparison between several insulin sensitivity indices and metabolic risk factors in overweight and obese postmenopausal women: a MONET study.

BACKGROUND AND AIMS: The purpose of this study was to compare the relationship of several insulin sensitivity indices with cardiometabolic risk factors in overweight and obese postmenopausal women. METHODS AND RESULTS: This was a cross-sectional study involving 137 overweight and obese postmenopausal women (age: 57.7+/-4.8 yrs; body mass index: 32.4+/-4.6 kg/m(2); body fat: 38.6+/-9.2 kg). Insulin sensitivity was determined by the euglycaemic-hyperinsulinemic (EH) clamp technique as well as by oral glucose tolerance test (OGTT) derived indices (Stumvoll, Matsuda and SI(is)) and fasting surrogate indices (HOMA, QUICKI). Cardiometabolic risk factors included: body composition and visceral fat that were measured using dual energy X-ray absorptiometry and computed tomography, respectively. Peak oxygen consumption, lower body muscle strength (using weight training equipment), physical activity energy expenditure (doubly labeled water), plasma lipids and C-reactive protein were also measured. Correlations of insulin sensitivity indices with metabolic risk factors showed some similarities, however, a wide range of variations were also observed. Furthermore, our results showed that visceral fat was the primary predictor for surrogate and OGTT indices, explaining 15-28% of the variance and the triglycerides/HDL-C ratio was the primary predictor for the EH clamp indices, explaining 15-17% of the variance. CONCLUSION: The present study indicates that the different methods of measuring and/or expressing insulin sensitivity display variations for associations with cardiometabolic risk factors. Therefore, interpretations of relationships between insulin sensitivity indices and cardiometabolic risk factors should take into account the method used to estimate and express insulin sensitivity.