Continued Loss in Visceral and Intermuscular Adipose Tissue in Weight-Stable Women Following Bariatric Surgery

OBJECTIVE: To assess changes in total adipose tissue (TAT), subcutaneous (SAT), visceral (VAT), and intermuscular (IMAT) by whole-body MRI before surgery, at 12 months and 24 months post-surgery in a subset of participants of the Longitudinal Assessment of Bariatric Surgery-2. DESIGN AND METHODS: From 0 to 12 months, n=20F and 3M; from 12 to 24 months, n=42F and 7M. Paired t-tests and GLM repeated measures examined changes in TAT, SAT, VAT, and IMAT at 12 and 24 months, with sex and age as covariates. RESULTS: Changes from 0 to 12 months, included weight (−41.9±12.1kg; −36%), TAT (−33.5±9.6kg; −56%), SAT (−29.2±8.2kg; −55%), VAT (−3.3±1.6kg; −73%), and IMAT (−0.99±0.68kg; −50%), all p<0.001. In females, from 12 to 24 months, despite relative weight stability (−1.8±6.5kg, −2%; p=0.085), VAT (−0.5±0.7kg; −30%; p<0.001) and IMAT (−0.2±0.4kg; −14%; p=0.012) decreased further. In males from 12 to 24 months, weight increased (5.1±5.2kg; 6%; p=0.04) with no significant changes in TAT or sub-depots. CONCLUSIONS: Bariatric surgery continues to induce favorable changes in body composition, i.e., persistent adipose tissue loss at 24 months in the absence of further significant weight loss.