1. Department of Internal Medicine, E-Da Hospital/I-Shou University, Kaohsiung, Taiwan
2. Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
3. Institute of Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
4. EpiPatterns, Haverhill, New Hampshire
5. Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts