Purpose: We aimed to investigate the relationship between the presence of the metabolic syndrome (MetS) and endothelial dysfunction in middle-aged subjects with signs of central obesity but without overt cardiovascular disease.

Methods: We studied 176 subjects (age 49.1 ± 6.4, 40% of males) diagnosed with central obesity according to the IDF criteria. Patients underwent the detailed evaluation of cardiovascular risk factors (including blood tests for high sensitivity C-reactive protein, fibrinogen, serum glucose and lipid profile) and the evaluation of endothelial function by ultrasound assessment of flow-mediated dilatation (FMD) in the brachial artery.

Results: Totally 120 subjects (68%) were diagnosed with MetS, 56 (32%) had isolated central obesity or central obesity plus one additional component of MetS. FMD was significantly lower in patients with MetS as compared to the subjects without it (6.4 ± 3.9% and 7.8 ± 3.9%, p=0.029), although groups did not differ significantly regarding age, gender, diameter of the brachial artery, family history and smoking status. Serum high sensitivity C-reactive protein (hsCRP) but not fibrinogen was higher in patients with MetS (p=0.013 and p=0.47, respectively). Logistic regression analysis revealed that the presence of MetS is significantly predicted by the decrease of high density lipoproteins and flow-mediated dilatation (p=0.0053 and p=0.0054).

Conclusion: Association between impaired endothelial function and the presence of metabolic syndrome suggests that the assessment of endothelial function can have an additive value in the discrimination of patients with MetS.