The Author Response: Comparison of Visceral Fat and Liver Fat as Risk Factors of Metabolic Syndrome

Abstract

We appreciate detailed and valuable comments on our article (1). We would like to clarify some of points raised about it. First, among several criteria to define fatty liver, liver attenuation value ≤ 40 Hounsfield units (HU) represents most accurate for moderate-to severe disease and is not quite sensitive for mild fatty liver comparing with other criteria (2, 3). However, subjects in our study were healthy adults who visited health promotion center and those who have moderate-to severe fatty liver were very rare. When liver attenuation value ≤ 40 was used to define fatty liver, subjects met this criterion were only 4 persons (3 males, 1 female). Therefore, we thought that ≤ 40 criterion was not suitable to define fatty liver in our study. Even if fatty liver defined by liver attenuation value ≤ 40 was used as an independent variable during regression analysis, fatty liver was still more important risk factor than visceral fat in our total subjects (odds ratio, fatty liver vs visceral fat; 13.2 vs 7.87). We could not find any evidence that ROI size should be relatively small (100-150 mm2) to measure liver attenuation. When measuring liver attenuation, more representative values can be obtained by making ROI as large as possible (at least 1 cm2) and avoiding inclusion of any large vessels or biliary structure (4). There were some typos in our article as mentioned in correspondence. We are sorry and would like to correct the interior lobe to left medial lobe in description of Fig. 1 and 30 to -190 HU to -30 to -190 HU to measure visceral fat area. About diagnostic criteria of metabolic syndrome in our study, we used modified NCEP-ATP III criteria with exception of waist circumference as described in our article. Finally, we agree that our study has several limitations including small sample size as we have mentioned in our article, and those limitations could potentially confound results. Additional well designed large-scale study is warranted to confirm our study.