Body fat distribution predicts the degree of endothelial dysfunction in uncomplicated obesity

OBJECTIVE: To ascertain in obesity the role of body fat distribution (the s trongest predictor of morbility and mortality in obese subjects) in determi ning the degree of endothelial dysfunction, an early marker of atherosclero tic disease. SUBJECTS: 18 premenopausal women with uncomplicated obesity excluding other cardiovascular risk factors and 12 age-matched slim healthy women. MEASUREMENTS: Endothelium-dependent vasodilation, studied as diameter varia tion in response to an increase in shear-stress, was evaluated in the right common femoral artery of obese and slim subjects by a non invasive approac h and compared to glyceril-trinitrate vasodilation. To characterize better the vascular functional and/or structural properties, we studied the arteri al wall distensibility by an echo-tracking system. Adipose tissue regional distribution was determined by computerised axial tomography. RESULTS: The endothelium-dependent vasodilation was significantly impaired in obese subjects (P < 0.005 versus non-obese subjects) while glyceril-trin itrate vasodilation and arterial distensibility were similar in the two gro ups. In our obese subjects endothelial-dependent vasodilation was inversely correlated to body fat distribution (visceral/subcutaneous adipose tissue ratio: r = -0.624, P = 0.0058). In contrast, metabolic parameters (except C -peptide response during oral glucose tolerance test (OGTT): r = -0.587, P = 0.01), blood pressure values and body weight did not correlate with the e ndothelial function. CONCLUSION: Uncomplicated obesity per se is characterised by an alteration of the endothelial function; the degree of this vascular damage is predicte d by body fat distribution independently of body weight and metabolic and o ther haemodynamic parameters, and correlates with an index of insulin secre tion.