Background: Bariatric surgery can be restrictive or malabsorptive depending on the adopted mechanism, and the two different types of surgery may exert different impacts on bodycomposition. So far in Taiwan, there is no study using the deuterium oxide dilution method to compare the impacts of different bariatric surgeries on the change of body fat composition.
Methods: A total of 47 obese subjects receiving bariatric surgery during 2008-2015 in National Cheng Kung University Hospital were recruited. Of the 47 subjects, 23 went through sleeve gastrectomy (male/female=9/14, mean age=36.9±9.7 years, mean body mass index (BMI)=45.4±8.8 kg/m2) and 24 received mini-gastric bypass surgery (male/female=16/8, mean age=40.6±11.6 years, mean BMI=43.2±9.5 kg/m2). Percent body fat and fat mass were determined by using deuterium oxide dilution method both before and 6 months after surgery. Waist circumference was also measured to assess abdominal fat distribution.
Results: At six months after surgery, subjects reported an average reduction in BMI, body fat percentage and insulin resistance by 23.4±8.7%, 22.4±18.4% and 47.2±50.6%, respectively. In comparison with sleeve gastrectomy, mini-gastric bypass achieved significantly greater reduction in body fat percentage (p<0.01) based on analysis by multiple linear regression (MLR) models with adjustment for age, sex, diabetes mellitus history, and baseline insulin resistance. The results also showed significantly greater reduction in fat mass (p<0.05) and body fat percentage (p<0.05) among subjects with diabetes mellitus and in fat mass (p<0.05) in subjects with higher preoperative insulin resistance.
Conclusion: Obese subjects undergoing either sleeve or mini-gastric bypass surgery achieved similar weight reduction and lost more than 20% of baseline body weight at 6 months after surgery. After mini-gastric bypass surgery, those diabetes patients and those with greater preoperative insulin resistance appeared to achieve better reduction of body fat composition.