Body Composition, Serum Sclerostin and Physical Function After Bariatric Surgery: Performance of Dual-Energy X-ray Absorptiometry and Multifrequency Bioelectrical Impedance Analysis.

Abstract

The aim of this study was to determine the effects of bariatric surgery and weight loss on body composition, serum sclerostin and physical performance. Seventy-three consecutive patients (36 non-surgical controls and 37 who underwent bariatric surgery) were evaluated by means of laboratory tests, multifrequency bioelectrical impedance analysis (BIA), total-body dual-energy X-ray absorptiometry (DXA), gait speed and handgrip strength. The differences between non-surgical and surgical patients were as follows: body mass index (BMI) 42.9 ± 5.7 vs 34.8 ± 6.0kg/m2 (p < 0.001); handgrip strength 31.3 ± 7.0 vs 27.1 ± 9.3kg (p < 0.033); skeletal muscle mass index (SMI)-BIA 12.3 ± 1.2 vs 10.6 ± 1.2kg/m2; fat-free mass index (FFMI)-BIA 21.9 ± 1.9 vs 18.9 ± 2.1k/m2 (p < 0.001 for all comparisons); Baumgartner-DXA 10.8 ± 1.5 vs 9.0 ± 1.4kg/m2 (p < 0.001); fat mass BIA 55.4 ± 12.5 vs 36.8 ± 9.6; fat mass DXA 54.3 ± 12.38 vs 35.1 ± 7.5kg (p < 0.001 for both comparisons) and serum sclerostin 30.9 ± 31.9 vs 26.9 ± 21.1pmol/L (p = 0.516). Positive correlation was found between BIA and DXA: SMI × Baumgartner (r = 0.842; p < 0.001) and fat mass (r = 0.970; p < 0.001). Gait speed was relatively preserved in sleeve gastrectomy (SG) compared with Roux-en-Y gastric bypass (RYGB) (1.2 ± 0.3 and 0.9 ± 0.1m/s; p = 0.038). Bariatric surgery leads to lower values of lean and fat mass and of handgrip strength with no differences in serum sclerostin concentrations. There was a positive correlation between BIA and DXA for fat and lean mass parameters. Physical performance was better after SG than in RYGB.