1. National Cheng Kung University Department of Public Health, College of Medicine, , Tainan 701, Taiwan
2. National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University Department of Emergency Medicine, , Tainan 704, Taiwan
3. National Cheng Kung University School of Medicine, College of Medicine, , Tainan 701, Taiwan
4. National Taiwan University Institute of Epidemiology and Preventive Medicine, College of Public Health, , Taipei City 100, Taiwan
5. National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University Department of Occupational and Environmental Medicine, , Tainan 704, Taiwan