Fig. 1

The number of 91 participating medical centers in the BE-China and their locations across China. Shanghai has enrolled twenty-five medical centers; Zhejiang enrolled fifteen medical centers; Jiangsu enrolled eleven medical centers; Guangdong enrolled five medical centers; Beijing enrolled four medical centers; Jiangxi enrolled four medical centers; Hunan enrolled two medical centers; Guangxi enrolled two medical centers; Hubei, Fujian, Guizhou, Henan, Liaoning, Ningxia, Sichuan, Xinjiang, Yunnan, Chongqing, Hebei, Shandong, Tianjin, Shaanxi, Inner Mongolia, Anhui, Gansu, Tibet, Qinghai, Heilongjiang, Jilin, Hainan, Shanxi enrolled one medical center each; Hong Kong, Macau and Taiwan did not enroll any medical center, respectively