2.1 Data sources
This study was conducted by MOOSE guidelines32. A search of the literature up to January 2020 was performed from the databases of PubMed, Web of Science, Wan fang, VIP (Chinese scientific and technical journal database) and CNKI (National Knowledge Infrastructure of China). The following search terms were used:exposure (“hysterectomy” or “surgical removal of the uterus”) and outcomes (“heart disease” or “CVD” or “cardiovascular disease” or “CAD” or “CHD” or “coronary artery disease” or “coronary heart disease” or “ischemic heart disease” or “hypertension” or “high blood pressure” or “stroke” or “arrhythmias” or “myocardial infarction” or “angina pectoris” or “heart failure”). The language was restricted to English and Chinese. Furthermore, relevant studies which were not captured by our database searches but listed as the bibliographies of selected articles were also included.