Objective. This study investigated relationships between adipose tissue deposition within skeletal muscle and morphological and biochemical variables in children with obesity. Methods. Fifty-one Japanese children (16 girls) aged 7 to 16 years were assigned to either mild (<20%), moderate (≥20% to <50%), or severe obesity groups (≥50%). Computed tomography images were taken to calculate the cross-sectional area (CSA) of muscle, subcutaneous and visceral adipose tissue (VAT, for abdomen only), and muscle signal intensities, as an index of intramuscular adipose tissue in the anterior, lateral, and posterior muscles of the abdomen and quadriceps, hamstring and adductor muscles in the thigh. Fasting blood samples were collected to measure plasma lipids, glutamate oxaloacetate transaminase, glutamate oxaloacetate transaminase, uric acid, glucose, and HbA1c. Results. Signal intensity in the severe obesity group was significantly lower than mild and moderate obesity groups in the abdomen and significantly lower than the moderate obesity group in the thigh. Stepwise regression analysis with signal intensity as dependent variable revealed that VAT CSA and age in abdominal muscles and VAT CSA, age, and triglycerides in thigh muscles are predictors of signal intensities. Conclusions. These results suggest that VAT CSA and age are predictors of intramuscular adipose tissue of the abdominal and thigh in children with obesity.
Keywords: intramuscular fat; obesity; visceral fat.