1. Department
of Environmental Health, School of Public Health, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea
2. Institute
of Health and Environment, School of Public Health, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea
3. Department
of Environmental and Occupational Health, Medical College, National Cheng Kung University, 138, Sheng-Li Rd., Tainan 70428, Taiwan