1 Department of General Surgery & Obesity and Metabolic Disease Center, China-Japan Friendship Hospital, Beijing, 100029, China.
2 Department of General Surgery & Obesity and Metabolic Disease Center, China-Japan Friendship Hospital, Beijing, 100029, China. Electronic address: xinfeidejia@sina.com.
3 Department of General Surgery & Obesity and Metabolic Disease Center, China-Japan Friendship Hospital, Beijing, 100029, China. Electronic address: menghuade@hotmail.com.