1. The Center of Gerontology and Geriatrics; West China Hospital, Sichuan University; Chengdu China
2. National Clinical Research Center for Geriatrics; West China Hospital, Sichuan University; Chengdu China
3. Chinese Clinical Trial Registry, Chinese Ethics Committee of Registering Clinical Trials; West China Hospital, Sichuan University; Chengdu China
4. Cochrane China; West China Hospital, Sichuan University; Chengdu China