What causes Alzheimer’s disease?
Research shows that the causes of Alzheimer’s disease probably include a combination of these factors:
- Age-related changes in the brain: Scientists are learning how age-related changes in the brain may harm neurons and affect other types of brain cells and contribute to Alzheimer’s damage. These changes include shrinking of certain parts of the brain, inflammation, and vascular damage.
- Genetics: Researchers have not found a specific gene that directly causes late-onset Alzheimer's disease. However, having one form, or allele, of the APOE gene, APOE ε4, increases a person's risk but does not mean that someone will definitely develop Alzheimer’s. Some people with an APOE ε4 allele never get the disease, and others who develop Alzheimer's do not have any APOE ε4 alleles. Researchers are investigating genetic variants like this that may increase or decrease a person’s risk.
- Health, environment, and lifestyle factors: Research suggests that a host of factors beyond genetics and age-related brain changes may play a role in the development and course of Alzheimer's disease. For example, eating a nutritious diet and engaging in physical activity can help prevent or control certain chronic conditions linked to a higher risk for dementia, such as heart disease, high blood pressure, diabetes, and obesity.