LEFT-VENTRICULAR MASS IN THE OBESE - INFLUENCE OF LEAN BODY-MASS

Systolic blood pressure and body mass index (BMI) are the main determi nants of the left ventricular mass (LVM). The mechanism of this cardia c hypertrophy in the obese individual is multifactorial and involves h emodynamic as well as metabolic factors. The association of LVM with t he morphologic features of the individual are well known. The aim of t his study was to assess the influence of the morphologic and metabolic features of obese women on LVM. 2D echocardiography evaluation of LVM was done in 24 normotensive, normoglycemic obese women (BMI [27.5-52. 2 Kg/m(2)). Lean and fat body mass were determined by bio-impedancemet ry, insulin sensitivity (Si) by the minimal model (Bergman), and basal metabolism by using indirect calorimetry. There was a positive correl ation between LVM and BMI (r = 0.61; p = 0.001), waist to hip ratio (r = 0.45; p = 0.03), basal metabolism (r = 0.61, p = 0.001), lean (r = 0.74, p = 0.0002) and fat (r = 0.49; p = 0.01) body mass. Fasting glyc emia was positively correlated with LVM (r = 0.62; p = 0.001), but not Si. LVM was also positively correlated to the triglyceride level. No relations were found with systolic or diastolic blood pressure. Multiv ariate regression analysis was performed to determine the relative con tribution of lean body mass (the morphologic variable with the best as sociation to LVM in univariate analysis), blood glucose, waist to hip ratio, age and triglycerides. The multiple r for the model was 0.87 (p < 0.001). Lean body mass and blood glucose were found to be the only significant and independent predictors of LVM (p = 0.001 and p = 0.03 respectively). We conclude that : 1) lean body mass is an important de terminant of LVM in obese normotensive individuals. Hence, in obese wo men, correcting LVM for lean body mass might be more accurate than cor recting it for body surface area or height. 2) There is no relationshi p between LVM and insulin sensitivity. The link between blood glucose and LVM needs to be studied further.