Epidemiological surveys have found that many factors are closely related to the occurrence and development of stroke. Risk factors for cerebrovascular diseases can be broadly divided into two major categories: those that are not intervenable, such as age, gender, genetics and race; and those that are intervenable, such as hypertension, diabetes mellitus and heart disease. Epidemiological studies show that the incidence and mortality of cerebrovascular diseases can be reduced through the intervention of risk factors, so a full understanding of the risk factors of cerebrovascular diseases is an important prerequisite for the prevention and treatment of cerebrovascular diseases. (1) Non-intervention risk factors (1) Age and gender: It is one of the important risk factors for stroke. Age and stroke incidence are positively correlated, and the incidence of stroke increases more than 1 times for every 10 years after the age of 55. (2) Genetics: There is a family history of stroke or a genetic predisposition to stroke. A history of stroke in both father and mother increases the risk of stroke in children. (3) Race: Stroke incidence and mortality rates vary widely by race, with stroke mortality rates in black people aged 45-55 years being 4-5 times higher than in white people. Asian countries such as China and Japan have a higher incidence of stroke. (1) Hypertension (hypertension) is the most important and independent risk factor for stroke, and an increased systolic or diastolic blood pressure is positively and linearly associated with the risk of cerebral hemorrhage or infarction. Studies have shown that the relative risk of stroke is approximately 4 times higher than normal in patients with systolic blood pressure >160 mmHg and/or diastolic blood pressure >95 mmHg, with small arterial hyalinosis, microinfarction or microaneurysm formation caused by long-term hypertension. The results of 17 international studies on antihypertension have shown that systematic antihypertensive treatment of about 50,000 patients reduced stroke incidence by 38% and fatal strokes by 40%. A 60% reduction in stroke mortality in the United States from 1960 to 1995 was associated with systematic antihypertensive therapy. (2) Heart diseases: Various heart diseases, such as heart valve disease, non-valvular atrial fibrillation, coronary heart disease, myocardial infarction, mitral valve prolapse, cardiac mucinous tumor and heart failure due to various causes increase the incidence of TIA (transient ischemic attack) and ischemic stroke, and heart disease is a definite risk factor for stroke. About 75% of patients with ischemic stroke die with heart disease, and effective prevention can reduce the incidence of cerebrovascular events. The prevalence of atrial fibrillation increases with age, and the prevalence of atrial fibrillation is 5.9% after the age of 65. About half of the cardiogenic cerebral embolisms are caused by atrial fibrillation, and warfarin anticoagulant therapy can reduce the risk of stroke due to atrial fibrillation by 68%. Patients with atrial fibrillation who do not have contraindications to anticoagulation, including elderly patients, are recommended to use warfarin reasonably to prevent stroke ② Heart valve disease: especially mitral stenosis is an important risk factor for stroke, and the Farmingham study showed that mitral annular calcification increased the risk of stroke exponentially after adjusting for other risk factors for stroke, and mitral annular calcium combined with atrial fibrillation increased the risk of stroke fourfold. Left atrial dilatation is also a risk factor for stroke. (iii) Coronary artery disease: increases the risk of stroke by a factor of 2. Left ventricular hypertrophy on ECG increases the risk of stroke by a factor of 3. Heart failure increases the risk of stroke by a factor of 4. The risk of stroke due to cardiac catheterization and endovascular therapy is 0.2% and 0.3%, respectively, and the incidence of stroke during peri-cardiac surgery is about 1%. Pacemakers and radiofrequency ablation can also cause complications such as cerebral embolism. (3) Diabetes mellitus (diabetes) is an independent risk factor for ischemic stroke. The risk of stroke in patients with abnormal glucose tolerance or diabetes mellitus increases exponentially compared to the general population. Patients with diabetes are prone to cerebral atherosclerosis, hypertension, obesity hyperlipidemia and ischemic stroke. An epidemiological survey of nearly 20,000 people with diabetes in Capital Steel found that the prevalence of ischemic stroke in the diabetic group was 3.6 times higher than that in the non-diabetic group, but the prevalence of hemorrhagic stroke was not significantly different from that in the control group, and that hyperglycemia can aggravate post-stroke brain injury. High blood glucose can cause elevated glycated hemoglobin, which has a high oxygen affinity and reduces tissue oxygen supply. (4) History of transient ischemic attack (TIA) or stroke: It is also an important risk factor for ischemic stroke, about 20% of cerebral infarction patients and about 30% of complete stroke patients have a history of TIA, about 1/3 of TIA patients have stroke sooner or later, and the annual incidence of stroke in TIA patients is 1%-15%. Carotid angiography often reveals intracranial carotid initiation plaque formation and stenosis in patients with TIA, and carotid endarterectomy can reduce recurrence of TIA and prevent strokes. (5) Hyperlipidemia and hyperfibrinogenemia: they increase blood viscosity and accelerate the process of cerebral atherosclerosis, and are important risk factors for hypertension and coronary heart disease. (6) Smoking and alcohol: Smoking increases the risk of ischemic stroke by a factor of 2 and is positively associated with the amount of smoking. Studies have shown that the risk of stroke is reduced within 2-4 years after stopping smoking. Smoking increases blood viscosity and hematocrit, and nicotine stimulation of sympathetic nerves can cause blood contraction and increase blood pressure. The incidence of stroke in alcoholics is 4-5 times higher than in the general population and significantly increases the risk of hemorrhagic stroke. Swedish study on the relationship between alcohol consumption and stroke mortality in 15,077 elderly people with 20 years of follow-up found that death from stroke was 769, of which 574 died of ischemic stroke, a small amount of alcohol consumption was not significantly related to ischemic stroke, and heavy alcohol consumption was closely related to hypertension, and the incidence of recent stroke in acute alcoholics was 65.3%. Alcohol consumption can cause small artery spasm and promote stroke. (7) Obesity and poor lifestyle: obese people are prone to hypertension, diabetes and hyperlipidemia, etc. Framingham believes that exceeding 30% of standard body weight is an independent risk factor for cerebral infarction. Bad lifestyle such as lack of exercise, low physical activity, improper diet (such as high salt intake and high intake of meat and animal oil), drug abuse and temper tantrums. In addition, infections, fundus arteriosclerosis and asymptomatic carotid murmur, as well as prethrombotic state due to hematologic disease or abnormal blood rheology are also associated with stroke occurrence. (8) Oral contraceptives: are susceptible to ischemic stroke. It is possible that estrogen in contraceptives may cause an increase in coagulation factors VIII, IX, X, prothrombin, platelet count and aggregation, increase in fibrinogen, decrease in red blood cell deformability, increase in whole blood viscosity and slow blood flow, and endothelial hyperplasia, leading to thrombosis. (9) Homocysteinemia: positively correlated with ischemic stroke and negatively correlated with blood folate and vitamin B12. Supplementation with vitamin B6, vitamin B12 and folic acid reduces blood homocysteine levels.