Relationship of Insulin Sensitivity and Left Ventricular Mass in Uncomplicated Obesity

OBJECTIVE: We studied uncomplicated obesity as a model to evaluate the influence of insulin sensitivity per se on left ventricular mass (LVM) and geometry. RESEARCH METHODS AND PROCEDURES: We selected 50 obese subjects (BMI > 30 kg/m(2); 38 women and 12 men; mean age, 38.4 +/- 10 years; BMI, 36.4 +/- 10.5 kg/m(2)) with normal blood pressure, glucose tolerance, and plasmatic lipid levels. Thirty lean subjects formed the control group. Each subject underwent euglycemic insulin clamp (7 pmol/min per kg) to evaluate whole body glucose use (M index) and echocardiogram to calculate LVM and indexed LVM. RESULTS: Insulin-resistant obese subjects had higher LVM, LVM/h(2.7), LVM/body surface area, and LVM/fat-free mass(kg) (p = 0.001; p = <0.001 p = 0.001, and p = 0.04, respectively) than obese subjects with normal insulin sensitivity. Multivariate regression analysis showed that M index was the strongest independent correlate of LVM (r(2) = 0.34; p = 0.03). DISCUSSION: Our findings showed that insulin resistance, in uncomplicated obesity, is associated with an increased LVM and precocious changes of left ventricular geometry, whereas preserved insulin sensitivity is not associated with increased LVM.