Data source

This retrospective study used data from the Health Management Centre of Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei, China. Tongji Hospital, which was founded in 1900, is the largest tertiary medical center in central China. The Health Management Centre of Tongji Hospital, with three branches, covers the entire Wuhan region, including the Jiangan District, Jianghan District, Qiaokou District, Hanyang District, Wuchang District, Chingshan District, Hongshan District, Caidian District, Jiangxia District, Huangpi District, Xinzhou District, Dongxihu District and Hannan District. Nowadays, routine health examinations have become very common in China, especially in big cities like Wuhan, as the central government is encouraging people to get regular medical checkups. The Tongji Hospital-Health Management Center provides routine medical examination service for individuals and groups, and has a database (TJ-HMCD) containing the electronic health records of persons of most occupations and retired persons living in residential communities of Wuhan. Therefore, the sample is comparatively representative and comprehensive. There are four optional medical checkup packages provided by the Health Management Centre: basic package, standard package A, standard package B and standard package C. Individuals or groups who buy packages B or C will receive more comprehensive health checks, in which homocysteine is tested as a risk marker for cardiovascular and cerebrovascular disease.

Data for this study were obtained from Database 2018 (TJ-HMCD2018) covering persons who received health screening within the time frame of January 1, 2018 to December 31, 2018. The HMCD2018 includes data of 118,540 persons and represents about 1.07% of the total population of Wuhan. There are no significant differences in age, gender, or healthcare costs between the TJ-HMCD2018 and the whole database (TJ-HMCD). The study protocol was approved by the Ethics Committee of Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology (TJ-IRB20191012). All research was performed in accordance with relevant guidelines and regulations. To protect patient privacy, all personal identification information was deleted before being released for research. Considering that the data for this study does not include personal identifying information (e.g., name, address, and identification number), the Ethics Committee of Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology waived the requirement for written informed consent for this de-identified study.