1. Department of Gerontology and Respiratory Diseases; Xiangya Hospital, Central South University, 136 Xiangya Road; Changsha Hunan 410008 People's Republic of China
2. Institute of Integrated Traditional Chinese and Western Medicine, Xiangya Hospital, Central South University; Changsha Hunan 410008 People's Republic of China
3. Thyroid Tumour Internal Medicine Department; Cancer Hospital affiliated to Xiangya School of Medicine, Central South University; Changsha Hunan 410013 People's Republic of China