1. National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, Beijing 100050, China
2. State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
3. Department of Public Health, Faculty of Medicine, Imperial College London, London W2 1PG, UK
4. Beijing Dong Cheng Center for Disease Control and Prevention, Beijing 100010, China
5. State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China