Obesity, weight loss, and vascular function.

Obesity promotes the development of several major cardiovascular risk factors. Moreover, excess adiposity may play a direct role in initiating atherosclerosis as fat cells are capable of affecting the systemic vasculature through a variety of mechanisms. Recent studies demonstrate that obesity per se may impair vascular endothelial function. This is important as endothelial dysfunction is a key factor in the pathogenesis of atherosclerosis and in triggering acute ischemic events. At present, few studies have determined the beneficial impact of weight loss on cardiovascular outcomes and mortality. However, several experiments have demonstrated that weight loss can lead to improvements in endothelial function, a validated surrogate marker of cardiovascular risk. The mechanisms whereby weight loss restores vascular health are likely multifactorial. However, the relative importance of reduced adiposity versus the specific dietary regimens prescribed, the role of concomitant exercise, and the direct effect of medications remain unclear. Several other unresolved issues such as the longevity of improvement, the amount of weight loss required, and whether the improvement in endothelial function actually translates into a reduction in cardiovascular events also remain to be determined. Nevertheless, lifestyle changes that lead to weight reduction are able to improve vascular function in overweight adults.