Contributorship statement
We thank for support by the sources of funding in this study. Study design and concept of this meta-analysis were carried out by Xiu Hua Wan, Jingshang Zhang, Jinda Wang and Shanshan Jin; Shanshan Jin and Jingshang Zhang conducted the data collection; Shanshan Jin and Kai Cao performed the data analysis; Ying Xiong, Guyu Zhu, Jing Li and Hailong He provided interpretation of the data. Shanshan Jin performed the first draft of the manuscript; Shanshan Jin, Jingshang Zhang, Jinda Wang and Xiu Hua Wan revised the manuscript and produced the final version; English polishing was done by Mayinuer Yusufu.