Researchers have discovered that Alzheimer's disease:

• is not a part of normal aging
• affects both men and women
• is more common in people as they age -- most people with the disease are over 65
• is not caused by hardening of the arteries
• is not caused by stress

Scientists are looking at three areas:

Family history
For a few families, there is a definite connection between family history and Alzheimer's disease. While for others, a family history of Alzheimer's disease puts them at greater risk than someone with no family history. Though knowledge in this area is growing, the connection to heredity is not fully understood.

The external environment
The cause of Alzheimer's disease may be in our environment -- perhaps something in the water, soil or air.

The internal environment
Alzheimer's disease may be caused by something within the body. It could be a slow virus, an imbalance of chemicals or a problem with the immune system.

Researchers today believe there is no single cause of Alzheimer's disease. Instead, they believe it is caused by a combination of factors. There is still much that we don't know about the disease, but researchers continue to look for causes.