1. School of Public Health, Ningxia Medical University, Yinchuan, China
2. Ningxia Key Laboratory of Environmental Factors and Chronic Disease Control, Ningxia Medical University, Yinchuan, China
3. State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
4. School of Public Health, Tianjin Medical University, Tianjin, China
5. Centre for Health Systems and Policy Research, Chinese University of Hong Kong, Hong Kong, China
6. CUHK Shenzhen Research Institute, Chinese University of Hong Kong, Shenzhen, China