THE BLOG

Alzheimer's Disease: You Can Reduce Your Risk

Nov 19, 2012 | Updated Jan 19, 2013

If I told you how to reduce your risk of developing Alzheimer's Disease (AD), would you do it?

My work as a geriatrician, seeing Alzheimer's patients and counseling hard-pressed families, makes me hope so.

My many conversations with people over 50, at dinner parties and elsewhere, who dread losing their memory, independence and self-control to Alzheimer's, make me hope so.

The fact that a recent poll suggested Alzheimer's is America's second most feared disease (after cancer), makes me hope so.

Amid all the difficult news about dementia, this may be one of the best reasons for hope: Contrary to widespread misconception, you have the power to lower your odds of getting dementia, even if specific medical interventions to prevent AD have yet to be identified.

Like every physician, I wish we had a treatment that could prevent or reverse this cruel disease that now afflicts more than 5 million Americans. But we don't, at least not yet. The hard truth is that, while there are medications that help slow the progression of symptoms in the early and middle stages of dementia (cholinesterase inhibitors, including Donezepil, brand name Aricept), nothing turns back the clock once Alzheimer's symptoms take hold.

What we do have, right now, is considerable knowledge about the risk factors that make it more or less likely that a person will develop Alzheimer's in the first place.

Most physicians now believe that the damage done by Alzheimer's is irreversible and that the best hope lies in preventing it. This is particularly true for people at higher risk. I believe passionately that we should all know what those risks factors are and work to turn them in our favor.

AD risk factors that you cannot change

There are two kinds of risk factors: those you can't control and those you can. Here are some risks factors that you should be aware of, even if you can't change them.

Family History: Having one parent with AD doubles your risk; two parents with AD puts you at five times greater risk.

Age: About 5 percent of Alzheimer's patients have early onset disease, but the vast majority of cases are late-onset. Seventy-four is the most common age for detection. Dementia is never an inevitable part of aging, but getting older is a risk factor. The number of Alzheimer's cases doubles every five years after age 65 and AD risk hits about 50 percent after age 85.

Genetics: People with two copies of the apolipoprotein (ApoE4) gene appear to be at about 10 to 15 times greater risk, and one copy triples the risk. That said, having one or even two copies of the gene does not mean you will definitely develop Alzheimer's. For this reason, most physicians do not recommend taking the blood test for ApoE4, except in research settings. (A different variant of the same gene, ApoE2, provides some protection against the disease.) New genes that increase risk continue to be identified, holding out promise for greater understanding of basic mechanisms, and, therefore, hope for prevention.

Multiple mutations of a number of genes are the most common cause of early-onset AD (before age 60). Members of these unfortunate families with such mutations definitely will develop AD.

On the bright side, earlier this year researchers reported an exciting discovery: a rare gene mutation that appears to offer strong protection against Alzheimer's, even for people at high genetic risk.

Being a woman: More women than men develop Alzheimer's Disease. Although women outlive men, and age is a powerful risk factor, the weight of evidence suggests that women are still at slightly higher risk than men. And there is no doubt that women bear the major burden of caregiving for persons of both sexes with AD.

Down's Syndrome: About half of all people with Down's Syndrome will develop symptoms of Alzheimer's by their 50s, but almost all at autopsy show the typical pathologic features of AD.

Risk factors that you can change

The lifestyle changes listed below are not revolutionary, except in this respect: You may never have realized they can cut your risk of dementia. And authorities say that every little bit helps.

"Alzheimer's disease whittles away cognitive reserve, which is the brain's ability to tolerate damage without loss of thinking abilities. Anything that can be done to avoid brain damage and/or increase cognitive reserve can potentially delay dementia symptoms," says Norman Relkin, M.D., Ph.D., founding director of the Weill Cornell Memory Disorders Program and a member of the Board of Directors of the American Federation for Aging Research.

"When I am asked in my clinical practice about Alzheimer's prevention, I recommend attending to reversible risk factors for other conditions that impact negatively on the brain, particularly stroke and heart disease," adds Dr. Relkin. "After addressing things such as high blood pressure, cholesterol and diabetes, the most actionable advice I can give is to make lifestyle changes, such as regular physical exercise, weight control and eating a heart-healthy diet."

Reduce your risk of stroke: The first and most important thing you can do is reduce your risk of stroke. Stroke and Alzheimer's share many risk factors and the likelihood of dementia is doubled after a stroke. While it's not clear exactly why, considerable evidence (some of it gathered by the unique Nun Study) shows that two brains with an identical burden of AD pathology (plaques and tangles) can function quite differently. The non-stroke affected brain is more likely to function well, and the stroke-affected brain is more likely to develop dementia, including those affected by so-called "silent strokes."

In lifestyle terms, this means being a fanatic about controlling your blood pressure and atherosclerosis (hardening of the arteries), as well as high cholesterol and diabetes. Quit smoking. Read more from me about stroke prevention here.

Avoid concussion and head trauma: From research on professional football players to World War II vets and boxers, the evidence is mounting that traumatic brain injury has lifelong consequences, one of which is a marked increase in Alzheimer's, as well as Parkinson's disease, depression and suicide risk. The worse the injury, the higher the risk. Professional football players' risk of death from Alzheimer's or ALS appears to be increased almost four times.

Treat depression: Suffering from depression in midlife, and especially later in life is associated with increased Alzheimer's risk. Highly effective treatment is available for depression and should be pursued. (See my advice in depression here.)

Increase your activity and exercise: You don't have to do a triathlon, but the more you move, the better your vascular health, which is directly related to many types of dementia. A recent study even suggested that jogging five times a week normalized the otherwise much elevated risk of people with two copies of the gene variant ApoE-4.

Control your diabetes: High glucose levels, including after meals, can double your lifetime risk for developing Alzheimer's.

Keep your mind alive: It's too much to say that doing crosswords and playing cards alone can stave off Alzheimer's, but there is a correlation between active brain engagement and reduced risk. A recent study suggested that lots of mental activity delays the onset of cognitive decline (although decline was also faster once it began). But if you only have time or energy for physical or cognitive exercise, it has recently been shown that, although both are good, physical exercise is better at keeping the brain healthiest.

Sleep better: Sleep apnea has long been recognized as a cause of decreased daytime alertness, but recent studies suggest it may also increase the risk of dementia. For the obese, weight loss alone can sometimes help to eliminate sleep apnea, but in many cases other medical interventions are required.

Lots of things in life are beyond our control, but we should all take heart from what we can do. I urge you to take a walk and eat a healthy snack to celebrate... before it's too late.

For more by Richard W. Besdine, M.D., click here.

For more on Alzheimer's disease, click here.