1. Department of Occupational Medicine, Buddhist Tzu Chi General Hospital and School of Medicine, Tzu Chi University, Hualien, Taiwan, Republic of China
2. Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University Hospital, Taipei, Taiwan, Republic of China
3. Department of Environmental and Occupational Medicine, National Taiwan University Hospital, Taipei, Taiwan, Republic of China
4. Department of Public Health, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China
5. Public Health Bureau, Miaoli, Taiwan, Republic of China