1. Department of Centers for Disease Control and Prevention of Xining; Xining Qinghai Province China
2. Department of Epidemiology; College of Public Health and Social Justice; Saint Louis University; Saint Louis MO USA
3. Department of Biostatistics; College of Public Health and Social Justice; Saint Louis University; Saint Louis MO USA
4. Department of Epidemiology and Biostatistics; School of Public Health; State University of New York; Albany NY USA
5. Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment; Department of Preventive Medicine; School of Public Health; Sun Yat-sen University; Guangzhou Guangdong Province China
6. Department of Epidemiology and Biostatistics; School of Public Health; Sun Yat-sen University; Guangzhou Guangdong Province China