Causes of Alzheimer's Disease

Scientists do not yet fully understand what causes AD. There probably is not one single cause, but several factors that affect each person differently. Age is the most important known risk factor for AD. The number of people with the disease doubles every 5 years beyond age 65.

Family history is another risk factor. Scientists believe that genetics may play a role in many AD cases. For example, familial AD, a rare form of AD that usually occurs between the ages of 30 and 60, can be inherited. However, in the more common form of AD that occurs later in life, no obvious family pattern is seen.

Scientists still need to learn a lot more about what causes AD. In addition to genetics, they are studying education, diet, environment, and infections to learn what role they might play in the development of this disease.