Fat-Free Mass and Skeletal Muscle Mass Five Years After Bariatric Surgery.

Abstract

ObjectiveThis study investigated changes in fat free mass (FFM) and skeletal muscle (SM) five years after surgery in participants from the Longitudinal Assessment of Bariatric Surgery-2 trial.MethodsA 3-compartment model assessed FFM, and whole-body magnetic resonance imaging (MRI) quantified SM mass prior to surgery (T0), 1 year (T1), 2 years (T2), and 5 years (T5) postoperatively in 93 patients (85% female, 68% Caucasian, age 44.2 ± 11.6 yrs) who underwent gastric bypass (RYGB), sleeve gastrectomy (SLEEVE), or adjustable gastric band (BAND). Repeated-measures mixed models were used to analyze the data.ResultsSignificant weight loss occurred across all surgical groups in females from T0 to T1. FFM loss from T0–T1 was greater after RYGB (mean±SE:−6.9±0.6 kg) than BAND (−3.5±1.4 kg; p<0.05). RYGB females continued to lose FFM (−3.3±0.7 kg; p<0.001) from T1 to T5. A subset of RYGB males and females with MRI-measured SM showed similar initial FFM loss while maintaining FFM and SM from T1 to T5.ConclusionsBetween 1 and 5 years following common bariatric procedures, FFM and skeletal muscle are maintained or decrease minimally. The changes observed in FFM and muscle during the follow-up phase may be consistent with aging.