1. From the Department of Respiratory and Critical Care Medicine, Clinical Research Center for Respiratory Disease, West China Hospital, Sichuan University, Chengdu, Sichuan, China;
2. Department of Clinical Nutrition, West China Hospital, Sichuan University, Chengdu, Sichuan, China; and
3. Pneumology Group, Department of Integrated Traditional Chinese and Western Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China;
4. Priority Research Center for Healthy Lungs, Hunter Medical Research Institute, University of Newcastle, New Lambton, New South Wales, Australia