1. Kaohsiung Chang Gung Memorial Hospital, and Chang Gung University College of Medicine, Kaohsiung City, Taiwan;
2. Department of Public Health, Chung Shan Medical University, Taichung, Taiwan;
3. Department of Family and Community Medicine, Chung Shan Medical University Hospital, Taichung, Taiwan;
4. Changhua Public Health Bureau, Changhua, Taiwan;
5. Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan;
6. Changhua Christian Hospital, Changhua, Taiwan;
7. Changhua Hospital, Ministry of Health and Welfare, Changhua, Taiwan;
8. School of Oral Hygiene, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan.