Author contributions
Study design: Ze Yang, Xiang Wang, Xi-gang Wan, Zong-hua Qiu, and Yong-liang Xia. Data collection: Ze Yang, Xiang Wang, Xi-gang Wan, Jia-li Chen, Man-hao Shi, and Shi-yi Zhang. Analysis: Ze Yang and Xiang Wang. Manuscript drafting, editing, and approval: All authors.