Si-Hoon Park and Kyung Won Shim risk factors.4 However, the study tested VED by determining hemodynamic and rheologic re- sponses to L-arginine, a technique that may be inadequate for screening or clinical applications. A simple and noninvasive form of pulse wave analysis to determine VED was recently intro- duced.5,6 In the present study, we used pulse wave analysis, combined with provocative phar- macological testing, to determine VED. To our knowledge, this is the first report to prospectively test the impact of weight reduction per se on VED by pulse wave analysis. The main finding of this study is that substantial weight reduction over a 12-week period can improve VED, and that visceral fat reduction is most strongly related to VED improvement in premenopausal obese women. Relationship between visceral adiposity and VED Adipose tissue acts as an endocrine organ and appears to secrete metabolic pro-inflammatory molecules. These cytokines are known to con- tribute to vascular inflammation and to regulate vascular endothelial function, an early indicator of atherosclerosis development. Moreover, visceral fat appears to produce these cytokines more ac- tively than other adipose tissues. Visceral fat cells show higher rates of catecholamine-induced lipolysis and express higher numbers of β1- and β2-adrenergic receptors and levels of glucocor- ticoid receptor mRNA, thus explaining the impor- tance of fat distribution.17 Aging and estrogen deficiency can play a role in changes in vascular endothelium. After menopause, the possibility of obesity-related complications is likely to increase. Other cardiovascular risk factors, such as hyper- tension, diabetes mellitus, hypercholesterolemia, and smoking are also associated with VED. Thus, we confined our study to premenopausal obese women without additional cardiovascular risk factors in order to reduce the effect of such factors on VED.18 In a previous study, we found that provocative pharmacological testing using NTG showed preserved endothelium-independent vaso- dilation in premenopausal, healthy, obese women. However, changes in AIx after the introduction of salbutamol nebulas, which induces vasodilation Yonsei Med J Vol. 46, No. 4, 2005 through vascular endothelial cells, was less evident in the obese group than in the non-obese group. The results of the present study suggest that endothelial vasodilatory function is reduced in premenopausal healthy obese women despite a similar level of arterial stiffness, thus confirming that visceral fat per se is highly associated with VED. Relationship between reduced visceral adiposity and improved VED Vascular endothelial function is affected by car- diovascular risk factors, hormones, and medica- tions. Factors that affect VED include hyperten- sion,19 hypercholesterolemia,20 aging,21 estrogen,22 smoking, diabetes mellitus,23 cholesterol-lowering agents,24,25 hormone replacement therapy,26,27 and physical inactivity.28 Weight reduction improves many of the conditions frequently associated with or co-occur with obesity. This raises the question of whether the restoration of vascular endothelial function by weight reduction in obese people is due to visceral adiposity reduction, an improve- ment in cardiovascular risk factors, or increased physical activity. A recent study4 demonstrated that a reduction of visceral adipose tissue in obese women is a more important factor than increased physical activity or improvement of cardiovas- cular risk factors in improving VED. The study4 showed that a reduction in adipose tissue by lipo- suction surgery improved VED and highlighted the importance of visceral adiposity reduction in and of itself in improving VED in obese women. Pulse wave analysis for the evaluation of VED Vascular endothelial cell function was measured using pulse wave analysis. The results of pulse wave analysis following the administration of salbutamol or NTG has been shown to correlate with the results of invasive methods based on acetylcholine infusion.5 The augmentation index was used to assess VED in the present study. Compared to established methods for assessing vascular endothelial function, AIx combined with a drug challenge is a non-invasive, simple, and convenient method that is useful for the early detection and assessment of VED.5,29 Recently,