1. Department of Geriatrics The Affiliated Hospital of Qingdao University Qingdao Shandong China
2. Qingdao Municipal Health Science and Technology Education Center Qingdao Shandong China
3. Institute of Endemic Diseases, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission of the People's Republic of China, School of Public Health Health Science Center of Xi'an Jiaotong University Xi'an, Shaaxi China