Author Contributions
Bo Hu was responsible for the concept and design of the study. Yan Wan, Quanwei He did the literature search and wrote the manuscript. Man Li, Yuanpeng Xia, Lei Zhang, Zhou Sun, Xiaolu Chen acquired and interpreted data. Shaoli Chen analyzed the data. David Wang revised the manuscript. Xingquan Zhao and Yongjun Wang did the administrative, technical, or statistical support.