1. State
Key Laboratory of Bioactive Substance and Function of Natural Medicines,
Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, 1 Xiannongtan Street, Beijing 100050, China
2. Taiyuan Centre for Disease Control and Prevention, Taiyuan 030012, China
3. Department
of Biostatistics, Harvard School of Public Health, Harvard University, Boston, Massachusetts 02115, United States
4. School
of Public Health, Shanxi Medical University, Taiyuan 030001, China