Effect of Laparoscopic Roux-en-Y gastric Bypass on Body Composition and Insulin Resistance in Chinese Patients with Type 2 Diabetes Mellitus

Abstract

This study aims to assess the effect of laparoscopic Roux-en-Y gastric bypass (LRYGB) on body composition, fat distribution, and insulin resistance (IR) in Chinese type 2 diabetes mellitus (T2DM) patients. Eighteen patients with T2DM were studied before and 3months post LRYGB. Fasting plasma glucose (FPG), fasting insulin (FINS), and triglyceride (TG) were measured. IR index was determined using the homeostasis model assessment of insulin resistance (HOMA-IR). Body composition and fat distribution were measured by dual-energy X-ray absorptiometry (DXA). Fat mass (FM), muscle mass (MM), bone mineral content (BMC), and percent fat mass (%FM) at the whole body and five body regions including the arms, legs, trunk, android, and gynoid were obtained from DXA scans. HOMA-IR decreased from 5.02 at baseline to 1.43 3months post LRYGB (p < 0.05). There was significant decrease in total and regional body mass and body fat (all p < 0.05). A significant reduction was observed in %FM at every tested body region (all p < 0.05). There was more fat mass loss (31.03%) in android region than any other tested body region. Preoperative android %FM was significantly correlated with IR (r = 0.49, p < 0.05). Changes in android FM showed significant correlations with changes in IR, FPG, FINS, and TG (r = 0.54, 0.64, 0.54, and 0.67, respectively; all p < 0.05). Body composition in Chinese T2DM patients is rebalanced after LRYGB. Reduction of central obesity can result in improvement of IR, and android fat distribution may be a good indicator of postoperative benefits for LRYGB.