Key Laboratory of Trace Elements and Endemic Diseases of National Health and Family Planning Commission, School of Public Health, Health Science Center.|Key Laboratory of Trace Elements and Endemic Diseases of National Health and Family Planning Commission, School of Public Health, Health Science Center.|Department of Radiation Oncology, First Affiliated Hospital, Health Science Center.|Key Laboratory of Trace Elements and Endemic Diseases of National Health and Family Planning Commission, School of Public Health, Health Science Center.|Key Laboratory of Trace Elements and Endemic Diseases of National Health and Family Planning Commission, School of Public Health, Health Science Center.|Key Laboratory of Trace Elements and Endemic Diseases of National Health and Family Planning Commission, School of Public Health, Health Science Center.|Key Laboratory of Trace Elements and Endemic Diseases of National Health and Family Planning Commission, School of Public Health, Health Science Center.|Key Laboratory of Trace Elements and Endemic Diseases of National Health and Family Planning Commission, School of Public Health, Health Science Center.|Key Laboratory of Trace Elements and Endemic Diseases of National Health and Family Planning Commission, School of Public Health, Health Science Center.|Key Laboratory of Biomedical Information Engineering of Ministry of Education, and Institute of Molecular Genetics, School of Life Science and Technology, Xian Jiaotong University, Xian, P.R. China.|Department of Biostatistics and Bioinformatics, Tulane University School of Public Health and Tropical Medicine.|Laboratory of Molecular and Statistical Genetics, College of Life Sciences, Hunan Normal University, Changsha, P. R. China.|Department of Biostatistics and Bioinformatics, Tulane University School of Public Health and Tropical Medicine.|Laboratory of Molecular and Statistical Genetics, College of Life Sciences, Hunan Normal University, Changsha, P. R. China.|Department of Biostatistics and Bioinformatics, Tulane University School of Public Health and Tropical Medicine.|Key Laboratory of Trace Elements and Endemic Diseases of National Health and Family Planning Commission, School of Public Health, Health Science Center.