Effects of weight loss on insulin sensitivity and arterial stiffness in overweight adults.

Obesity is characterized by metabolic and vascular abnormalities. We examined the effects of weight loss on insulin sensitivity and arterial stiffness in overweight adults. Twelve (9 females; 3 males) overweight (body mass index, 30.3 +/- 3.7) adults (54.9 +/- 3.9 years) without diabetes or vascular disease were counseled by a registered dietician to lose weight over 6 months. Vascular structure, function, and wall mechanical properties were measured via ultrasound. Intravenous glucose tolerance test, 24-hour blood pressure, body composition (dual-energy x-ray absorptiometry), and lipids were also assessed. There were significant reductions in body mass (86.3 +/- 14.2 vs 79.5 +/- 13.8 kg, P < .0001) and percentage of fat (44.3% +/- 7.0% vs 41.0% +/- 8.5%, P < .01) after weight loss. There were significant improvements in total cholesterol (6.0 +/- 0.9 vs 5.0 +/- 0.8 mmol/L, P < .0001), low-density lipoprotein cholesterol (3.9 +/- 0.7 vs 3.2 +/- 0.6 mmol/L, P < .0001), triglycerides (3.4 +/- 2.3 vs 2.4 +/- 0.9 mmol/L, P < .05), and insulin sensitivity (3.3 +/- 1.7 vs 5.4 +/- 1.6 microU x 10(-4) min(-1) mL(-1), P < .0001) after weight loss. Brachial artery compliance (P < .05) and distensibility (P < .05) curves over the physiologic pressure range improved, whereas endothelial function and intima-media thickness remained unchanged. In overweight adults, 6 months of weight loss resulted in improvements in body composition, insulin sensitivity, lipid profile, and brachial artery compliance and distensibility.