1. Department of Preventive Medicine, School of Medicine, Kyung Hee University, Seoul, Korea.
2. Department of Occupational and Environmental Medicine, Bucheon Daesung Hospital, Bucheon, Korea.
3. Department of Physical Education, Graduate School, Sangji University, Wonju, Korea.
4. Department of Family Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University, School of Medicine, Seoul, Korea.
5. Total Healthcare Center, Kangbuk Samsung Hospital, Sungkyunkwan University, School of Medicine, Seoul, Korea.