Alzheimer’s disease accounts for 60 to 80 percent of dementia among the elderly.
The Centers for Disease Control and Prevention lists Alzheimer’s disease as the sixth-leading cause of death in the United States in 2010. Although dementia strikes 5 percent of people in their 70s, by age 90 more than one-third of Americans will be cognitively impaired to some extent. More than 83,000 people succumbed to Alzheimer’s in that year, as it ranked behind heart disease, cancer, lower respiratory conditions, strokes and accidents as a leading cause of death.
Alzheimer’s disease is not the only cause of dementia. Other conditions that lead to chronic memory loss and decrease in executive function of the brain include dementia due to strokes, Parkinson’s disease, head trauma, chronic infections and endocrine problems. Armed with an understanding of dementia as a public-health challenge, we can begin to think about prevention.
Some researchers hypothesize that treatment of “modifiable risk factors” for heart disease and stroke may also decrease the risk of Alzheimer’s disease, perhaps by as much as 25 percent. These risk factors include high blood pressure, diabetes and high cholesterol. No one, however, has proven that treating these chronic health conditions decreases dementia rates. Nonetheless, since the brain is a vascular structure, it makes intuitive sense to safeguard our overall health status as a way of improving our mental agility as we age.
Vitamins are sometimes cited as potential ways to decrease dementia rates. Unfortunately, high doses of vitamin E actually may increase overall mortality rates. Studies of vitamins B-6 and B-12 showed no benefit in preventing Alzheimer’s disease. The Physicians Health Study found that among 4,052 doctors enrolled, administration of beta-carotene supplements did not protect against development of dementia. Vitamin D deficiency may hasten cognitive decline, suggesting that vitamin D supplementation may be reasonable for some elders.
A diet rich in fish and omega-3 fatty acids, or fruits and vegetables, may be heart-healthy, but has not been proven to prevent dementia. The Women’s Health Initiative study found no benefit to consuming estrogen in preventing female dementia. Some researchers believe that anti-inflammatory drugs, such as ibuprofen or naproxen, may protect the aging brain against inflammation. These medicines have side effects, however, and are not approved or recommended for prevention of dementia.
Head trauma damages neurons directly, a phenomenon called “diffuse axonal injury.” As neurologists and pathologists begin to study brain damage in football players in more detail, post-concussive dementia is emerging as an area of concern in former athletes. In childhood, preventing head injuries includes wearing a helmet while skateboarding, bicycling or skiing. I occasionally see a young skateboarder flying down a hill with no helmet. Although a fractured wrist bone can be fixed, the delicate tissue of the central nervous system is not as resilient.
We cannot live our lives in a bubble, of course. Preventing dementia, however, should involve consideration of preventing brain injuries, especially in our young friends and relatives.
Books and CDs are often marketed to seniors, purporting to foster mental exercises that prevent memory loss. As a geriatrician, I believe that involvement in church activities, music or hobbies accomplishes just as much, at a lower cost. Teaching and mentoring youth, for example, keeps many an elder mentally sharp and upbeat. A good friend of mine teaches piano and accordion, and remains mentally agile as an octogenarian. Studies also suggest that regular aerobic exercise may prevent brain deterioration with age.
Future research will very likely improve strategies for preventing Alzheimer’s disease, and other dementias. Social and physical engagement, however, will also remain cornerstones of a healthy approach to growing older. As they say, “you either use it, or you lose it.”
Scott Anderson, M.D., Ph.D. ([email protected]) is a clinical professor of medicine, division of rheumatology, UC Davis. This column is informational, and does not constitute medical advice.