1. Department of Health Policy and Management, Johns Hopkins University Bloomberg School of Public Health , Baltimore, MD , USA
2. Department of Geriatrics, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences , Beijing , China
3. Wilmer Eye Institute, Johns Hopkins University School of Medicine , Baltimore, MD , USA
4. Ageing and Health (AAH) , Department of Maternal, Newborn, Child & Adolescent Health & Ageing (MCA), , Geneva , Switzerland
5. World Health Organization , Department of Maternal, Newborn, Child & Adolescent Health & Ageing (MCA), , Geneva , Switzerland
6. National Clinical Research Center for Geriatric Diseases , Xuanwu Hospital, , Beijing , China
7. Capital Medical University , Xuanwu Hospital, , Beijing , China
8. School of Health Policy and Management , Peking Union Medical College, , Beijing , China
9. Chinese Academy of Medical Sciences , Peking Union Medical College, , Beijing , China
10. Shenzhen People's Hospital , Shenzhen , China