Baseline of visceral fat area and decreased body weight correlate with improved pulmonary function after Roux-en-Y Gastric Bypass in Chinese obese patients with BMI 28–35 kg/m2 and Type 2 diabetes: a 6-month follow-up

Background: Associations between demographic data and pulmonary function have not been adequately examined in patients that underwent Roux-en-Y Gastric Bypass (RYGB). This study was designed to examine changes in body fat distribution and metabolic parameters after RYGB and whether these changes correlated with improved lung function. Methods: A retrospective review of 32 ethnic Chinese with obesity with body mass index (BMI) 28–35 kg/m and type 2 diabetes (T2DM) was conducted, focusing on metabolic outcomes and pulmonary function 6 months after RYGB. Results: Forced expiratory volume during first second (FEV1), percentage of forced expiratory volume during first second (FEV1 [%pred]), forced vital capacity (FVC), and percentage of forced vital capacity (FVC [%pred]) all improved significantly after RYGB. These increases all were negatively correlated with decreases in body weight and visceral fat area (VFA). The improvements of FEV1, FEV1 [%pred] and FVC were also negatively correlated with baseline of body weight and VFA. Furthermore, increases in FEV1 and FVC were independently associated with baseline of VFA (β = −0.003, P = 0.000; β = −0.004, P = 0.002, respectively). Conclusions: The baseline of VFA and weight loss induced by RYGB independently correlated with improved pulmonary function in Chinese patients.