1. Department of Epidemiology and Biostatistics, Xiangya School of Public health, Central South University , Changsha, Hunan , China
2. Xiangya Nursing School, Central South University , Changsha, Hunan , China
3. Department of Geriatrics, Xiangya Hospital, Central South University , Changsha, Hunan , China
4. National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University , Changsha, Hunan , China
5. Hunan Provincial Key Laboratory of Clinical Epidemiology , Changsha , China