The following types of elderly people are prone to dementia: 1. The chances of dementia occurring in later generations with a family history of dementia are higher than others; 2. The chances of dementia occurring in widows and widowers living alone are high; 3. The chances of dementia occurring in elderly people with chronic underlying diseases, such as hypertension, diabetes and hyperlipidemia, which are not well controlled, and who have had a stroke; 4. The chances of dementia occurring in elderly people with bad habits, such as smoking and long-term alcohol abuse, which have a certain degree of damage to their cognitive function; 5. The chances of dementia occurring in people with intracranial infections, viral encephalitis, or even intracranial occupying lesions, tumors and sequelae of trauma are also significantly higher.