Background: A visceral fat area of more than 100 cm2 as measured by computed tomography (CT) at the umbilical level has been included as a criterion for obesity in all the proposed criteria for metabolic syndrome. However, CT cannot be used frequently because of radiation exposure. We evaluated the usefulness of measurement of the serum levels of nitric oxide (NO), instead of CT and the waist circumference, as a marker of abdominal visceral fat accumulation.
Material/Methods: The study was carried out in 80 subjects. The serum levels of NO metabolites (nitrate/nitrite) were measured using the Griess reagent.
Results: Simple and multiple regression analysis revealed that the serum levels of NO metabolites showed the greatest degree of correlation with the visceral fat area (r=0.743, p<0.0001), and corresponded to a visceral fat area of 100 cm2, as determined using the ROC curve, was 21.0 µmol/ml (sensitivity 88%, specificity 82%); this method was more sensitive than the waist circumference for evaluation of the visceral fat accumulation.
Conclusions: Measurement of the serum levels of NO metabolites may be a simple, safe, convenient and reliable method for the evaluation of visceral fat accumulation in clinical diagnostic screening.

Keywords: Nitric Oxide - blood, Nitric Oxide Synthase Type II - metabolism, Nitrates - blood, Intra-Abdominal Fat - metabolism, Circadian Rhythm - physiology, Biological Markers - blood, Adipocytes - enzymology, Nitrites - blood, Regression Analysis, Waist Circumference - physiology