1. Department of Public Health, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
2. Department of Psychiatry, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
3. Institute of Behavioral Medicine, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
4. Department of Psychiatry, Tainan Hospital, Ministry of Health and Welfare, Tainan 700, Taiwan
5. Department of Occupational Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
6. Institute of Allied Health Sciences, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
7. Biostatistics Consulting Center, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
8. Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, 35 Siaodong Rd., Tainan 704, Taiwan