USC Health Now

Alzheimer’s disease affects more than five million Americans and is the most common form of dementia. Recent research points towards potential treatments as well behaviors that can raise or lower disease risk.

by Mel Cowan

According to Lon S. Schneider, M.D., there is no single, clear-cut cause of the late onset of Alzheimer’s, appearing after age 65 and more commonly in the late 70s and early 80s. Rather, he says, it appears to be caused by a combination of factors such as family history, educational level, head trauma, high cholesterol and blood pressure. None of these factors alone cause the disease, but each may contribute to a raised risk of developing Alzheimer’s.

Schneider, professor of psychiatry, neurology and gerontology at the Keck School of Medicine of USC, states that in the extremely rare cases of early-onset Alzheimer’s, appearing in people as young as mid-30s to 40s, the cause is a single gene mutation that causes increased production of a toxic form of amyloid protein. The mutation runs in families, so if there is no family history, there is little risk of early-onset Alzheimer’s.

While a genetic predisposition for the disease seems obvious, it would appear unlikely that a person’s level of education would have any effect. Not so, says Schneider. The specific reasons remain unclear, but research indicates that more years of formal education translates into less risk of developing Alzheimer’s. Schneider suggests that denser synapse networks formed in the brain when studying and learning create a “functional reserve” of neurons that thwart the progress of Alzheimer’s.

This “use it or lose it” method of prevention is the basis of the Religious Orders Study. This ongoing, long-term Alzheimer’s study, funded by the National Institutes of Aging, asked 700 participants to detail the amount of time they spent in seven activities that involve “significant information processing.” These included reading the newspaper, listening to the radio and playing puzzle games. After four years, participants who most often engaged in these activities were 47 percent less likely to develop Alzheimer’s symptoms than the participants who reported the least amount of activity.

Additional studies suggest that specific memory training, especially if it is computer-based, can enhance cognitive abilities in both healthy adults over age 65 and patients suffering from mild Alzheimer’s symptoms, with effects lasting for months.

However, for people who are worried about their level of brain-building, Schneider counsels, “Don’t start reading Proust to stop Alzheimer’s, but keep mentally active doing what you’ve always done. If you enjoy crossword puzzles and they engage your brain, keep at it.”

Schneider says a simple rule of thumb for delaying the symptoms of dementia is to keep your body and brain healthy. An ample supply of blood to the brain is paramount, he says, since anything that reduces that blood supply can contribute to Alzheimer’s. High blood pressure—which can damage blood vessels in the brain and disrupt nerve cell circuitry—is itself a risk factor of Alzheimer’s.

Equally dangerous as a risk factor is diabetes. Large-scale population studies have shown a correlation between type 2 adult-onset diabetes and Alzheimer’s. A number of current clinical studies are examining the specific link between Alzheimer’s and insulin production, and there are clinical trials assessing whether certain diabetes drugs might help control Alzheimer’s symptoms.

Occasional memory loss after age 40 is common, but if lapses become frequent or have negative consequences, a doctor should be consulted. Schneider says, “Early detection of memory loss is good on a number of fronts, in that it allows patients to plan, to compensate and adopt strategies that can both slow the onset of the disease, as well as prepare their families for when the condition worsens.”

Along with several other sites across the United States, USC is participating in a large-scale clinical trial on the efficacy of DHA, an omega-3 fatty acid, as a preventive factor in Alzheimer’s. As an antioxidant, DHA relieves oxidative stress in the brain, which contributes to neural damage. Schneider stresses that anyone interested in participating in this clinical trial or others should contact the Alzheimer’s Disease Education and Referral Center at the National Institute of Aging at (800) 438-4380, or by email at adear@nia.nih.gov.

“Volunteering for any of these trials contributes to a continually growing body of knowledge not only about the specific condition being studied, but about the brain as a whole and how we age,” says Schneider. He also points out that age is not a factor in volunteering because the large number of trials present opportunities for people of all ages.

As with any brain condition, there are layers of mystery to Alzheimer’s. Schneider says the good news is that by keeping healthy for other reasons, such as reducing the risks for heart disease or adult-onset diabetes, then the risks for developing Alzheimer’s is also being reduced.

“Cardiovascular health strategies like watching your diet and exercising, combined with keeping an active mind, never hurt and may ultimately slow the onset of Alzheimer’s,” concludes Schneider.