Visceral and subcutaneous adipose tissue FDG uptake by PET/CT in metabolically healthy obese subjects

OBJECTIVE: To measure FDG uptake in visceral (VAT) and subcutaneous (SAT) adipose tissue of metabolically healthy obese (MHO) and metabolically abnormal obese (MAO) compared to metabolically healthy lean (MHL) subjects. Given that MHO have increased metabolic risk, we hypothesized that MHO and MAO display similar VAT FDG uptake. DESIGN AND METHODS: We examined 18F-FDG-PET/CT studies of 141 adults (n=60 MHL, n=20 MHO, n=61 MAO) to determine VAT and SAT volumes and FDG uptake. Data on CVD risk factors (BMI, abdominal circumference, blood pressure, serum lipids, and fasting plasma glucose) were collected. RESULTS: MHO and MAO had similar VAT FDG uptake (P=0.74), both significantly lower than MHL (P<0.01) independent of age and gender. SAT FDG uptake was similar across all groups (P>0.2) independent of age and gender. In all groups, VAT FDG uptake was higher than SAT (P<0.0001). In separate sub-analyses of obese groups, VAT FDG uptake was more broadly negatively associated with whole-body adiposity than SAT FDG uptake, and FDG uptake in abdominal adipose depots was positively associated with liver density (P<0.05). CONCLUSIONS: FDG uptake in VAT of MHO is similar to MAO and lower than MHL, suggesting these subjects may present similar VAT dysfunction.