1. School of Public Health, Guangzhou Medical University, Guangzhou, China
2. Department of Chronic Disease Prevention, Qingdao Municipal Center for Disease Control & Prevention, Qingdao, China
3. University of California, Davis, Sacramento, CA
4. Qingdao Endocrinology and Diabetes Hospital, Qingdao, China
5. Department of Public Health, University of Helsinki, Helsinki, Finland
6. Department of Statistics and Epidemiology, Medical College, Qingdao, China