No drug yet found offers protection against Alzheimer's

Q: I've heard that certain common medicines used for other purposes may also protect against Alzheimer's disease. Is there any truth to this?

A: You've raised an important question. Unfortunately, research has not so far provided a clear answer.

Hormone therapy

For years, doctors believed that hormone therapy might protect women from Alzheimer's disease. This therapy replaces the hormones that a woman no longer makes after menopause.

The possibility that hormone therapy might offer protection was raised by studies which found that women who took estrogen were less likely to develop Alzheimer's than those who didn't.

These were "observational" studies: Large numbers of women taking hormone therapy as they entered menopause were compared to women of the same age who were not taking hormone therapy. The women were usually between the ages of 45-55.

Because observational studies can sometimes produce misleading results, a large randomized clinical trial, the Women's Health Initiative Memory Study, was conducted. Such trials are regarded as stronger evidence than observational studies. The women in the study were in their 60s.

The women who took estrogen-progestin hormone therapy were twice as likely to develop dementia as women who did not use hormones. The researchers found that estrogen by itself (without progestin) also increased the risk.

This study and others also found that hormone therapy increased the women's risk of strokes. Strokes themselves can cause dementia.

In my opinion, hormone therapy may have different effects depending on a woman's age.

There is much evidence of this in the relationship of hormone therapy and heart disease. Hormone therapy among women entering menopause (in the 45-55 age range) may indeed be protective, whereas it may increase the risk of Alzheimer's disease in older women.

In any event, hormone replacement therapies now carry warning labels stating that they increase the risk of dementia. I surely do not recommend that women should take hormone therapy with the goal of protecting themselves against Alzheimer's disease.

Cholesterol drugs

Statins are popular and effective cholesterol-lowering drugs. Some studies have found that they may lower the risk for Alzheimer's disease, but other studies have failed to find this effect.

NSAIDs

Examples of NSAIDs include ibuprofen (Advil, Motrin), naproxen (Aleve) and aspirin. Several studies have suggested that using NSAIDs can lower the risk of Alzheimer's disease. However, other studies contradicted these results.

Scientists think that NSAIDs may protect against Alzheimer's by reducing inflammation in the brain. And some experimental evidence suggests that ibuprofen may decrease the production and accumulation of beta-amyloid, the harmful clumps of protein found in the brains of people with Alzheimer's.

But regular use of NSAIDs has a variety of possible side effects. These include stomach problems such as bleeding and ulcers. And frequent use of non-aspirin NSAIDs may increase the risk of a heart attack or stroke.

So, there are no drugs that I would currently recommend for the purpose of protecting against Alzheimer's disease. Several drugs show promising results, but are in the early stages of testing. I am hopeful they will work.

• Dr. Anthony Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.