1. Department of Geriatrics, Respiratory Medicine, Xiangya Hospital of Central South University, Changsha 410008, China
2. Department of Respiratory Medicine, Xiangya Hospital of Central South University, Changsha 410008, China
3. Department of Geriatrics, Xiangya Hospital of Central South University, Changsha 410008, China
4. Department of Geriatrics, Clinical Laboratory, Xiangya Hospital of Central South University, Changsha 410008, China
5. Department of Biochemistry & Biology, University of South China, Hengyang 421001, China