1. Qingdao Centers for Disease Control and Prevention, Qingdao 266033, China.
2. Qingdao Institute of Preventive Medicine, Qingdao 266033, China.
3. School of Public Health, Guangzhou Medical University, Guangzhou 510000, China.
4. Department of Endocrine and Diabetes, Weifang Medical College, Weifang 261000, China.
5. Qingdao Endocrinology and Diabetes Hospital, Qingdao 266033, China.
6. Department of Epidemiology and Health Statistics, Qingdao University Medical College, Qingdao 266021, China.
7. Department of Public Health, University of Helsinki, FI00014, Helsinki, Finland.