Comprehensive body composition assessment

Trained technicians obtained measurements of height, weight, circumferences of the waist and hip, and chest depth [12 (link)]. 3T MRI scanners (Siemens TIM Trio at UH and General Electric HDx at USC) were used. An abdominal scan was acquired to quantify VAT areas (square centimeters) at 4 intervertebral segments of the intra-abdominal cavity (L1–L2, L2–L3, L3–L4, L4–L5) using an axial gradient-echo sequence with breath holds [12 (link)]. The average VAT across the segments L1-L5 was used in analysis. Whole-body composition, including total fat mass and muscle mass, was determined by a DXA scan (Hologic Discovery A fan-beam densitometer at UH and USC, Bedford, MA) [12 (link)]. Extensive details regarding the imaging protocol, as well as quality control calibration and estimation of VAT and SAT area were previously published [12 (link)].