1. Department of Occupational and Environmental Medicine, International St. Mary’s Hospital, Catholic Kwandong University, Beon-gil, Seo-gu, Incheon, Korea
2. Department of Statistics, Dongguk University, Jung-gu, Seoul, Korea
3. Occupational Safety and Health Research Institute, Korea Occupational Safety and Health Agency, Jung-gu, Ulsan, Korea
4. Department of Occupational and Environmental Medicine, Inha University Hospital, Inha University, Jung-gu, Incheon, Korea
5. Department of Occupational Health, Daegu Catholic University, Hayang-eup, Gyeongsan-si, Gyeongbuk, Korea
6. Department of Environmental Health, Korea National Open University, Jongro-gu, Seoul, Korea