Preventive drug treatments?
Experts agree that Alzheimer's, like other common chronic conditions, usually develops as a result of complex interactions among multiple factors, including age, genetics, environment and lifestyle, and coexisting medical conditions. While there is nothing an individual can do to change some risk factors — like age or genetics — research in these areas may lead to new ways to detect those at risk and offer preventive treatments.
For example, as development of potentially disease-modifying drugs continues, genetic testing could one day become a valuable tool to identify individuals who might benefit from early, proactive intervention to reduce risk. Currently, routine clinical testing for Alzheimer's genes is not recommended, since no preventive treatments are available.
Learn more about the drug treatment horizon
The risk of developing Alzheimer's or vascular dementia appears to increase as a result of many conditions that damage the heart or blood vessels. These include high blood pressure, heart disease, stroke, diabetes and high cholesterol. Some autopsy studies show that as many as 80 percent of individuals with Alzheimer's disease also have cardiovascular disease.
A longstanding question is why some people develop hallmark Alzheimer's plaques and tangles but do not develop the symptoms of Alzheimer's. Vascular disease may help researchers eventually find an answer. Autopsy studies suggest that plaques and tangles may be present in the brain without causing symptoms of cognitive decline unless the brain also shows evidence of vascular disease. Many experts believe that controlling cardiovascular risk factors may be the most cost-effective and helpful approach to protecting brain health.
Some of the strongest current evidence links brain health to heart health. Your brain is nourished by one of your body's richest networks of blood vessels. Every heartbeat pumps about 20 to 25 percent of your blood to your head, where brain cells use at least 20 percent of the food and oxygen your blood carries.
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Physical exercise and diet
Regular physical exercise may be a beneficial strategy to lower the risk of Alzheimer's and vascular dementia. Some evidence suggests exercise may directly benefit brain cells by increasing blood and oxygen flow. Even stronger evidence suggests exercise may protect brain health through its proven benefits to the cardiovascular system. Because of the known cardiovascular benefits, a medically approved exercise program is a valuable part of any overall wellness plan.
Like exercise, diet may have its greatest impact on brain health through its effect on heart health. The best current evidence suggests that heart-healthy eating patterns, such as the Mediterranean diet, also may help protect the brain. A Mediterranean diet includes relatively little red meat and emphasizes whole grains, fruits and vegetables, fish and shellfish, and nuts, olive oil and other healthy fats.
Catalyst to progress
The Alzheimer's Association was among the first to encourage investigation of the impact of vascular factors on Alzheimer's disease. We have funded such studies for more than 20 years and continue to highlight this promising avenue of research into potentially modifiable risk factors. Learn more about our commitment to research.
Social connections and intellectual activity
A number of studies indicate that maintaining strong social connections and keeping mentally active as we age might lower the risk of cognitive decline and Alzheimer's. Experts are not certain about the reason for this association. It may be due to direct mechanisms through which social and mental stimulation protect the brain. Alternatively, people who eventually develop Alzheimer's may feel less inclined to engage in socially and intellectually stimulating activities years before current diagnostic methods can detect symptoms.
Catalyst to progress
Animal studies can be especially helpful in increasing our knowledge about direct mechanisms through which physical and mental stimulation may benefit the brain. Orly Lazarov, PhD, received a 2007 Alzheimer's Association New Investigator Research Grant to explore the impact of physical activity and an enriched environment on mice genetically engineered to carry one of the human genes that causes Alzheimer's disease. Her results showed that physical and mental stimulation appear to decrease hallmark Alzheimer's pathologies and support new nerve cell growth and better cell-to-cell communication.
There appears to be a strong link between future risk of Alzheimer's and serious head trauma, especially when injury involves loss of consciousness. You can help reduce your risk of Alzheimer's by protecting your head.
- Wear a seat belt
- Use a helmet when participating in sports
- "Fall-proof" your home
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What you can do now
While research is not yet conclusive, certain lifestyle choices, such as physical activity and diet, may help support brain health and prevent Alzheimer's. Many of these lifestyle changes have been shown to lower the risk of other diseases, like heart disease and diabetes, which have been linked to Alzheimer's. With few drawbacks and plenty of known benefits, healthy lifestyle choices can improve your health and possibly protect your brain.
Learn more about brain health.
You can help increase our knowledge by considering participation in a clinical study. Prevention and risk management studies need healthy participants who are willing to make a long-term commitment to moving the field forward. You can find prevention trials currently recruiting in our new TrialMatch tool.
Understanding prevention research
Here are some things to keep in mind about the research underlying much of our current knowledge about possible prevention:
- Insights about potentially modifiable risk factors apply to large population groups, not to individuals. Studies can show that factor X is associated with outcome Y, but cannot guarantee that any specific person will have that outcome. As a result, you can "do everything right" and still have a serious health problem or "do everything wrong" and live to be 100.
- Much of our current evidence comes from large epidemiological studies such as the Honolulu-Asia Aging Study, the Nurses' Health Study, the Adult Changes in Thought Study and the Kungsholmen Project. These studies explore pre-existing behaviors and use statistical methods to relate those behaviors to health outcomes. This type of study can show an "association" between a factor and an outcome but cannot "prove" cause and effect. This is why we describe evidence based on these studies with such language as "suggests," "may show," "might protect," and "is associated with."
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- The gold standard for showing cause and effect is a clinical trial in which participants are randomly assigned to a prevention or risk management strategy or a control group. Researchers follow the two groups over time to see if their outcomes differ significantly.
- It is unlikely that some prevention or risk management strategies will ever be tested in randomized trials for ethical or practical reasons. One example is exercise. Definitively testing the impact of exercise on Alzheimer's risk would require a huge trial enrolling thousands of people and following them for many years. The expense and logistics of such a trial would be prohibitive, and it would require some people to go without exercise, a known health benefit.
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Selected reports and resources
- "The Healthy Brain Initiative: A National Public Health Road Map to Maintaining Cognitive Health"
The Centers for Disease Control and Prevention and the Alzheimer's Association, 2007. (70 pages)
The Alzheimer's Association and the Centers for Disease Control and Prevention convened a multidisciplinary steering committee and a panel of invited experts to establish a plan to make brain health part of our national wellness agenda.
- "Preventing Alzheimer's Disease and Cognitive Decline: Evidence Report/Technology Assessment Number 193."
Williams, John W., Plassman, Brenda L., et al. Agency for Healthcare Research and Quality, Department of Health and Human Services, April 2010.
This expert panel convened by the National Institutes of Health (NIH) evaluated the strength of evidence for a wide range of risk factors implicated in Alzheimer's disease, including nutritional issues, medical conditions and prescription and non-prescription medications, social/economic/behavioral factors, toxic environmental influences, and genetics. Although there is consistent evidence linking many factors to reduced risk, the panel concluded that evidence is not yet strong enough to recommend any specific strategies to prevent Alzheimer's disease.
- "The NIH Cognitive and Emotional Health Project: Report of the Critical Evaluation Study Committee."
Hendrie, Hugh C.; Albert, Marilyn S.; Butters, Meryl A.; et al. Alzheimer's & Dementia: The Journal of the Alzheimer's Association, January 2006; Vol. 2 (1): 12–32.
An expert panel appointed by the National Institutes of Health (NIH) to assess current scientific knowledge about brain health and identify promising areas for further research finds that heart health, physical activity, freedom from chronic illness and a strong social support system may all help maintain mental sharpness and emotional well-being as we age. The panel identifies more than 40 factors that may influence cognitive and emotional health in older adults. Some of the most consistent findings link high blood pressure, diabetes, stroke and excess weight to an increased risk of cognitive decline.
- "The Aging Mind: Opportunities in Cognitive Research."
Stern, Paul C. and Carstensen, Laura, editors. Committee on Future Directions for Cognitive Research on Aging; National Academy Press, Washington, D.C., 2000.
In 1999, the National Institute on Aging (NIA) asked the National Research Council to evaluate current understanding of how cognitive function changes with age and to identify future directions for research. The result was this 288-page report summarizing our current state of knowledge and recommending areas of greatest need and potential for further insight. Includes an extensive bibliography.
- "Achieving and Maintaining Cognitive Vitality with Aging."
Fillitt, Howard M.; Butler, Robert N.; O'Connell, Alan. W.; Albert, Marilyn S.; and others. Mayo Clinic Proceedings 2002; 77: 681 – 696.
Co-sponsored and reviewed by the National Institute on Aging (NIA), this overview article summarizes recent research assessing the impact of various lifestyle factors and medical conditions on the health of the aging brain. Includes an extensive reference list.
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