1. Key Laboratory of Trace Elements and Endemic Diseases, Collaborative Innovation Center of Endemic Disease and Health Promotion for Silk Road Region, School of Public Health, Health Science Center, Xi’an Jiaotong University , No. 76 Yan Ta West Road, Xi’an 710061 , China
2. Key Laboratory for Disease Prevention and Control and Health Promotion of Shaanxi Province , Health Science Center, Xi'an Jiaotong University, Xi’an 710061 , China
3. Key Laboratory of Environment and Genes Related to Diseases of Ministry of Education of China , Health Science Center, Xi'an Jiaotong University, Xi'an 710061 , China