ALZHEIMER’S DISEASE

Risk Factors for Alzheimer’s

The exact cause(s) of Alzheimer’s remain(s) unknown. Risk factors associated with the disease include environment, life style and, more certainly, age and family history.

Age

Most people with Alzheimer’s are over 65, although people in their forties and fifties have been diagnosed with the disease. It is therefore important to see a doctor as soon as one or more symptoms appear.

Diabetes

It has been known for some time that type 2 (adult) diabetes is a risk factor for Alzheimer’s disease. It was generally assumed that this was because the blood vessel and heart disorders associated with diabetes are also risk factors for Alzheimer’s disease. It is also known that the utilization of glucose is impaired in the brains of people with Alzheimer’s disease, somewhat resembling the situation in the bodies of people with diabetes.

New research tells us that the impairment in the Alzheimer brain may be because the brain is in a sort of diabetic state, even through the person may not be diabetic in the ordinary sense. It seems that in the brain of a person with Alzheimer’s disease, either the production of insulin in the brain is reduced for some reason or the brain cells are becoming insensitive in insulin.

Down Syndrome

Almost all individuals with Down syndrome over the age of 40 have changes to brain cells typical of Alzheimer’s disease. Alzheimer’s disease usually develops when these individuals are in their 50s or 60s.

Mild Cognitive Impairment (MCI)

In MCI, there is a level of cognitive and/or memory impairment beyond that expected for normal aging but not sufficiently advanced to be called “dementia” or “Alzheimer’s disease.” It is estimated that 85% of people with MCI will develop Alzheimer’s disease within ten years, making MCI an important risk factor for the disease. As researchers believe that abnormal changes in the brain may begin as early as 5-10 years before there are signs of Alzheimer’s disease, brain imaging may make it possible to detect the most at-risk individuals with MCI. Research into the progression of MCI is ongoing.

Head injury

Brain injuries, especially repeated concussions, are risk factors for the later development of Alzheimer’s disease.

Low levels of formal education

Several studies have shown that people who have less than six years of formal education appear to have a higher risk of developing Alzheimer’s disease. Education as a protective factor requires more study to determine whether it is education itself that makes a difference or other factors related to it (e.g., low income level).

Aluminium

Most researchers no longer regard aluminium as a risk factor for Alzheimer’s disease. However, some researchers are still examining whether some people are at risk because their bodies have difficulties in handling foods containing the metals cooper, iron, and aluminium.

Menopause

Twice as many women as men get Alzheimer’s disease. This is partly due to their living longer than men on average, partly because women are more prone than men to get diabetes, but also in large part because in post-menopausal women there is a decline of the important hormone estrogen. For many years, estrogen has been prescribed to relieve symptoms of menopause. Despite a recent large-scale clinical study on women, which recommended discontinuation of Hormone Replacement Therapy (HRT) because it was both ineffective and had potentially dangerous side effects, a number of clinical researchers continue to regard it as worthy of further study. Any decision regarding the use of HRT should be made in consultation with a physician.

Other Risk Factors

In addition to the risk factors described above, all of the following have been documented as risk factors for Alzheimer’s disease: chronic inflammatory conditions (such as certain forms of arthritis), a history of episodes of clinical depression, strokes or “ministrokes,” high cholesterol, high blood pressure, stress, inadequate exercising of the brain and obesity. Risk factors that are less firmly established include smoking, excessive alcohol consumption and taking drugs.

Family History

People who have a parent, sister or brother with Alzheimer’s are at greater risk of developing the disease than those with no family history of it.

A low percentage of people with the disease have the hereditary form. This rare form is known as the autosomal dominant form of Alzheimer’s disease. In some families, it is transmitted directly from one generation to the next. Having more than one family member with Alzheimer’s does not necessarily mean that your family suffers from the hereditary form of the disease. Only a very small percentage of people with Alzheimer’s have the hereditary form.

Related Disorders

A person may sometimes display the following symptoms:

• Memory loss;
• Changes in behaviour and uncommon reactions;
• Difficulties with speech and movement.

Those symptoms could signal disorders that are related to Alzheimer’s disease, such as:

• Creutzfeldt-Jakob disease;
• Lewy body dementia;
• Fronto-temporal dementia;
• Vascular dementia.

For more information about related disorders, please visit the Web site of the Alzheimer Society of Canada: www.alzheimer.ca

Myth and Reality