About the Authors

Xiaoyun Liang

Affiliation School of Social Development and Public Policy, Beijing Normal University, Beijing, China

Hong Guo

Affiliation School of Social Development and Public Policy, Beijing Normal University, Beijing, China

Chenggang Jin

Affiliation School of Social Development and Public Policy, Beijing Normal University, Beijing, China

Xiaoxia Peng

niuniu@ccmu.edu.cn (XP); Zhang99@bnu.edu.cn (XZ)

Affiliation School of Public Health and Family Medicine, Capital Medical University, Beijing, China

Xiulan Zhang

niuniu@ccmu.edu.cn (XP); Zhang99@bnu.edu.cn (XZ)

Affiliation School of Social Development and Public Policy, Beijing Normal University, Beijing, China

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: XL XP CJ XZ. Analyzed the data: XL XP. Contributed reagents/materials/analysis tools: XL XP. Wrote the paper: XL. Literature review: XL. Acquisition of data: XL HG. Data extraction: XL HG. Critical revision of the manuscript: XP XZ CJ.