Aging is the main risk factor for all types of dementia. Some diseases that cause dementia (such as early-onset Alzheimer's disease and some frontotemporal dementias) may run in families.

You have a greater chance of developing vascular dementia if you:

• Are male.
• Have high blood pressure (hypertension).
• Have had a heart attack.
• Have atherosclerosis, a buildup of fat and calcium in the arteries, which can lead to coronary artery disease.
• Have diabetes.
• Have high cholesterol.
• Have had a stroke or transient ischemic attack (TIA).

Other factors that may increase your risk of dementia include:

• Having ongoing low blood pressure if you are older than 75. Researchers think this risk may be the result of the brain not getting enough blood. More studies are needed to determine the best blood pressure for older adults, one that lowers their risk for heart disease but provides enough blood flow to keep the brain healthy.³
• Having a high level of homocysteine. Homocysteine is an amino acid normally found in small amounts in the blood. High levels of homocysteine are thought to cause plaque to build up in the blood vessels. Over time, this can lead to serious problems such as stroke, heart attack, and pulmonary embolism. It may also lead to mental declines. Homocysteine levels are generally stable until age 40 but then begin to increase naturally, especially after age 70.⁴
• Using hormone therapy after the age of 65. Hormone replacement therapy (HRT)-a combination of estrogen and progesterone-was once believed to provide protection from dementia or cognitive impairment. However, the Women's Health Initiative found that HRT actually increased the risk for Alzheimer's disease and other dementias in women age 65 and older who took it for more than 4 years.⁵ Estrogen alone (estrogen replacement therapy) had similar effects.⁶ Whether either of these therapies might help reduce the risk of later dementia when used around the age of menopause is not known.⁷