The Impact Of Adiposity And Insulin Resistance On Endothelial Function In Middle-Aged Subjects

Objectives: To investigate the relationship between adiposity, adipose distribution, insulin resistance (IR) and vascular endothelial function. Methods: Flow-mediated endothelium-dependent dilation (EDD), body mass index (BMI), waist circumference, waist hip ratio and IR index (HOMA-IR) were measured in 527 healthy subjects (328 males) aged between 35 to 55 years. The relations between these parameters and endothelial function was studied using univariate and multivariate linear regression analysis. Results: Waist circumference, waist hip ratio and HOMA-IR were greater in the overweight or obese subjects (p<0.01). They were also greater in males than in females within the same body weight group (p<0.05). The incidence of vascular endothelial dysfunction in the normal body weight, overweight and obese was 30.7%, 69.5% and 75.4% respectively (p<0.05). A higher waist circumference and waist hip ratio was also found in male subjects with endothelial dysfunction than those without. A greater HOMA-IR was identified in both male and female subjects with impaired endothelial function (p<0.05). Multivariate linear regression analysis showed a small but significant inverse correlation between endothelial function and BMI (r= -0.285, p<0.001), waist hip ratio (r= -0.179, p<0.001) and HOMA-IR (r= -0.164, p<0.001). Conclusions: Adiposity and adipose distribution have an important impact on endothelial function in male subjects. An increase in HOMA-IR is associated with vascular endothelial dysfunction in both males and females.