Assessing Your Risk for Alzheimer's Disease
(from the Mayo Clinic)

Not every moment of forgetfulness is a sign of Alzheimer's disease. Everyone has occasional memory lapses. However, there are factors that may increase your risk of developing the disease.

Alzheimer's disease affects brain tissue directly, causing progressive brain deterioration in middle or late life. So far, only age and heredity are proven risk factors. But like cancer and cardiovascular disease, Alzheimer's probably results from a combination of factors.

Researchers are studying:

Age — Alzheimer's usually affects people older than age 65, but can, rarely, affect those younger than age 40. The average age at diagnosis is about 80.

Only one to two people in 100 have Alzheimer's at age 65, but that risk increases to about one in five by age 80. By age 90, half of all people have some symptoms. The incidence of Alzheimer's is about the same for all races, but women are more likely than men to develop the disease, in part because they live longer.

Heredity — Family history plays a role in about 40 percent of people with early onset Alzheimer's. If your parents or a sibling developed Alzheimer's, you're more likely to as well. But, even in families with several people who've had Alzheimer's, most members don't get it.

It's clear that most Alzheimer's involves some disease process in addition to a genetic vulnerability.

Environment — Researchers are studying environmental factors to discover both possible causes and preventions of Alzheimer's. For example, some people with Alzheimer's have small deposits of aluminum in their brains. But scientists who've studied environmental aluminum sources from antacids and antiperspirants to cooking pots and drinking water haven't found a link between aluminum and Alzheimer's.

On the other hand, some studies hint at a possible protective effect from estrogen, nonsteroidal anti-inflammatory drugs (NSAIDs), vitamin E and other factors. But more research is needed to confirm any benefit.

Can you reduce your risk?

Scientists are combing the environment for clues about ways to delay or prevent Alzheimer's disease and to reduce risk of the disease.

They're following several hopeful, but very preliminary, leads:

NSAIDs — A long-term study released in June 1996 showed that the nonsteroidal anti-inflammatory drugs (NSAIDs) ibuprofen (Advil, Motrin, Nuprin), naproxen sodium (Aleve) and indomethacin (Indocin) reduced risk of Alzheimer's by 30 percent to 60 percent. Doctors think brain inflammation occurs as one stage in the development of Alzheimer's.

Investigators were uncertain why aspirin, which is also an anti-inflammatory drug, and acetaminophen (Tylenol), which is not, had no effect.

The study reinforced an earlier one that compared NSAID use in twins. That study found that a twin who used NSAIDs regularly, usually for arthritis, was 10 times less likely to develop Alzheimer's than the twin who wasn't taking an NSAID. But, doctors don't recommend taking NSAIDs, which can cause gastrointestinal bleeding, solely to prevent Alzheimer's until more research confirms these results.

Vitamin E and selegiline — An ongoing study at several sites, including Mayo, is looking at vitamin E and selegiline (Eldepryl), a drug used to treat Parkinson's disease, for a possible protective effect against the progression of Alzheimer's. These substances may slow the rate of decline in people with moderately severe Alzheimer's.

Vitamin E and selegiline are antioxidants and may prevent nerve cell damage by destroying toxic free radicals. Free radicals are byproducts of normal cell metabolism. Some scientists think free radicals are discharged by immune cells that are in the brain responding to chronic brain inflammation from Alzheimer's. The free radicals may attach to molecules in the nerve cell membrane and disrupt function.

Estrogen — Alzheimer's disease in older women may be related to estrogen deficiency. Estrogen may interact with nerve growth factors and delay the degeneration of neurotransmitters that facilitate memory and learning.

Recent studies show that estrogen replacement after menopause can reduce a woman's risk of developing Alzheimer's by 30 percent to 40 percent. And evidence is growing that estrogen replacement therapy can improve mental abilities, especially verbal memory, in women who already have Alzheimer's. But because the impact of estrogen is still not proven, you shouldn't begin replacement therapy solely to prevent Alzheimer's.

Mental fitness — Another study shows that maintaining mental fitness may delay onset of dementia. The study focused on a large order of nuns reported to have significantly lower rates of Alzheimer's, even though their average age is 85 and many are in their 90s.

The study is intriguing because most other environmental factors affecting the nuns, such as diet and environment, are the same. Many of the nuns have advanced academic degrees and lead an intellectually challenging life into old age.

Some researchers believe that lifelong mental exercise and learning may promote the growth of additional synapses, the connections between neurons, and delay the onset of dementia.

Other researchers argue that advanced education gives a person more experience with the types of memory and thinking tests used to measure dementia. This advanced level of education simply may help some people "cover" their condition until later.

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