The etiology of Alzheimer’s disease is very complex, mainly including the following: 1) age factor, the incidence of Alzheimer’s disease tends to increase with age; 2) brain degenerative diseases, such as Alzheimer’s disease; 3) cerebrovascular diseases, such as cerebral infarction and cerebral hemorrhage; 4) genetic factors; 5) endocrine diseases, such as hypothyroidism and parathyroidism; 6) nutritional and metabolic disorders, such as vitamin B12 deficiency; 7, metabolic disorders caused by malignant tumors and autoimmune encephalitis; 8, drug and other substance poisoning, such as chronic alcoholism can cause cognitive dysfunction, as well as rare long-term exposure to chemical toxic substances, such as aluminum, mercury, gold, silver, arsenic and lead can cause dementia; 9, carbon monoxide poisoning is also a common cause of acute dementia; 10, other traumatic brain injury or epilepsy Continuous seizures and normal pressure hydrocephalus can also cause dementia; 11. Long-term emotional depression, isolation, solitude, widowhood, illiteracy, low language level, lack of physical and mental exercise, etc. in the elderly can also accelerate the process of brain aging and induce dementia.