1. Department of Gynecology and Obstetrics Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences Beijing China
2. The First People's Hospital of Yunnan Province Affiliated Hospital of Kunming University of Science and Technology Kunming China
3. Department of Obstetrics, The First People's Hospital of Yunnan Province Affiliated Hospital of Kunming University of Science and Technology Kunming China
4. Chinese Academy of Medical Sciences and Peking Union Medical College Beijing Hospital Beijing China
5. Department of Epidemiology, The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Beijing Hospital, National Center of Gerontology Institute of Geriatric Medicine, Chinese Academy of Medical Sciences Beijing China
6. The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences Beijing China