About the Authors

Yunxia Liu

Contributed equally to this work with: Yunxia Liu, Xianjun Wang

Affiliation Department of Epidemiology and Biostatistics, School of Public Health, Shandong University, Jinan, China

Xianjun Wang

Contributed equally to this work with: Yunxia Liu, Xianjun Wang

Affiliation Shandong Center for Disease Control and Prevention, Jinan, China

Yanxun Liu

Affiliation Department of Epidemiology and Biostatistics, School of Public Health, Shandong University, Jinan, China

Dapeng Sun

Affiliation Shandong Center for Disease Control and Prevention, Jinan, China

Shujun Ding

Affiliation Shandong Center for Disease Control and Prevention, Jinan, China

Bingbing Zhang

Affiliation Department of Epidemiology and Biostatistics, School of Public Health, Shandong University, Jinan, China

Zhaohui Du

Affiliation Department of Epidemiology and Biostatistics, School of Public Health, Shandong University, Jinan, China

Fuzhong Xue

xuefzh@sdu.edu.cn

Affiliation Department of Epidemiology and Biostatistics, School of Public Health, Shandong University, Jinan, China

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: YXL XJW FX. Performed the experiments: YXL YL BBZ FX. Analyzed the data: YXL BBZ ZHD. Contributed reagents/materials/analysis tools: XJW DPS SJD. Wrote the paper: YXL.