1. Department of Preventive Medicine, Chosun University Medical School, Gwangju, Korea.
2. Department of Preventive Medicine & Institute of Wonkwang Medical Science, Wonkwang University College of Medicine, Iksan, Korea.
3. Jeonnam Regional Cancer Center, Chonnam National University Hwasun Hospital, Hwasun, Korea.
4. Department of Preventive Medicine, Chonnam National University Medical School, Gwangju, Korea.