Age - Alzheimer's disease is the most common for of dementia. About 1/3 of people 85 and older show signs of the disease.
Heart disease - Heart disease could lead to heart attack or stroke, which makes dementia more likely. It is usually caused by plaque buildup in arteries around your heart which slows blood flow to the brain, making it harder to think well or remember things.
Diabetes - People with diabetes are more likely to have damaged blood vessels. This can slow or block blood flow to the brain, and damage areas of the brain, leading to what's called vascular dementia.
High Cholesterol - Some research shows that high cholesterol in midlife could be risk for Alzheimer's disease later in life, but the exact link isn't clear.
Depression - Scientists aren't yet sure that it's a cause. It may be an early symptom or sign of other causes like Parkinson's and Huntington's disease.
Head Injury - Severe or repeated hits or falls could double or quadruple your chances, even years after the first time.
Genes - Genes seem to matter more in some types of dementia than others. However, dementia doesn't always run in families. If you are thinking about genetic testing for Alzheimer's, ask your doctor about the pros and cons associated with genetic testing.