1. Department of Gerontology and Geriatrics Shengjing Hospital of China Medical University Shenyang Liaoning China
2. Department of Health Statistics School of Public Health China Medical University Shenyang Liaoning China
3. Department of General Practice Medicine Nanyang Centre Hospital Nanyang Henan China
4. Department of Clinical Epidemiology Shengjing Hospital of China Medical University Shenyang Liaoning China
5. Institute of Health Sciences China Medical University Shenyang Liaoning China