1. Research Centre for Public Health, Tsinghua University, Beijing, China.
2. Centre for Health Economic Experiments and Public Policy, Shandong University, Jinan, China.
3. Division of Neurogeriatrics, Karolinska Institutet, Stockholm, Sweden.
4. Ageing Research Centre, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm University, Gävlegatan 16, 113 30 Stockholm, Sweden.