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

OBJECTIVE: To ascertain in obesity the role of body fat distribution (the strongest predictor of morbility and mortality in obese subjects) in determining the degree of endothelial dysfunction, an early marker of atherosclerotic 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 variation 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 approach and compared to glyceril-trinitrate vasodilation. To characterize better the vascular functional and/or structural properties, we studied the arterial 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-trinitrate vasodilation and arterial distensibility were similar in the two groups. 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 endothelial function. CONCLUSION: Uncomplicated obesity per se is characterised by an alteration of the endothelial function; the degree of this vascular damage is predicted by body fat distribution independently of body weight and metabolic and other haemodynamic parameters, and correlates with an index of insulin secretion.