BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any reliance Supplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open Appendix Table 1: Participants’ geographic distribution (26 provinces, 100 cities) Region Provinces/Municipality City Beijing Beijing Tianjin Tianjin Cangzhou Langfang North Qinhuangdao Hebei Shijiazhuang Baoding Tangshan Shanghai Shanghai Nanjing Zhenjiang Yangzhou Suqian Xuzhou Jiangsu Changzhou Wuxi Taizhou Suzhou Lianyungang Nantong Hangzhou Huzhou Wenzhou Lishui East Zhejiang Ningbo Jiaxing Jinhua Shaoxing Taizhou Maanshan Hefei Anhui Xuancheng Huainan Fuyang Xiamen Fuzhou Fujian Sanming Quanzhou Shangrao Jiangxi Ganzhou Nanchang Hall BJ, et al. BMJ Open 2021; 11:e048012. doi: 10.1136/bmjopen-2020-048012 BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any reliance Supplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open Jiujiang Jinan Linyi Qingdao Shandong Weifang Liaocheng Weihai Taian Luoyang Zhengzhou Henan Shangqiu Anyang Nanyang Huangshi Wuhan Central Jingzhou Hubei Xiangyang Yichang Xianning Changsha Hunan Hengyang Xiangtan Guangzhou Foshan Shenzuo Zhongshan Guangdong Zhaoqing Yangjiang Dongzuo South Huizhou Zhuhai Yulin Guangxi Nanning Hainan Haikou Changde Hongkong Hongkong Chengdu Yibin Zigong Sichuan Southwest Mianyang Dazhou Neijiang Guizhou Guiyang Hall BJ, et al. BMJ Open 2021; 11:e048012. doi: 10.1136/bmjopen-2020-048012 BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any reliance Supplemental material placed on this supplemental material which has been supplied by the author(s) BMJ Open Yunnan Kunming Chongqing Chongqing Ningxia Yinchuan Xian Shanxi Xianyang Northwest Jilin Changchun Jilin Songyuan Baicheng Heillongjiang Haerbin Jinzhou Fushun Northeast Shenyang Liaoning Anshan Fuxin Dalian Appendix Table 2: Participants’ originated countries (6 continents, 77 countries) Continent Country Afghanistan Bangladesh Georgia India Indonesia Iran Malaysia Nepal Asia Pakistan Philippines Pakistan Saudi Arabia Syria Tajikistan Thailand Uzbekistan Britain England France Germany Europe Great Britain Italy Russia Sweden Hall BJ, et al. BMJ Open 2021; 11:e048012. doi: 10.1136/bmjopen-2020-048012.