1. Institute of Public Health, National Yang Ming Chiao Tung University, Yang-Ming Campus, Taipei City, Taiwan
2. Institute of Statistical Science, Academia Sinica, Taipei City, Taiwan
3. Department of Obstetrics and Gynecology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei City, Taiwan
4. Institute of Community Health Care, National Yang Ming Chiao Tung University, Yang-Ming Campus, Taipei City, Taiwan