will everyone get alzheimer's?

Older age does not cause Alzheimer's, but it is the most important known risk factor for the disease. The number of people with Alzheimer's disease doubles about every 5 years beyond age 65. About one-third of all people age 85 and older may have Alzheimer's disease.

Although scientists have conducted many studies, and more are ongoing, so far nothing has been proven to prevent or delay dementia caused by Alzheimer's disease. But researchers have identified promising strategies and are learning more about what might—and might not—work.

We know that changes in the brain can occur many years before the first symptoms of Alzheimer's appear. These early brain changes point to a possible window of opportunity to prevent or delay debilitating memory loss and other symptoms of dementia. While research may identify specific interventions that will prevent or delay the disease in some people, it's likely that many individuals may need a combination of treatments based on their own risk factors.

Researchers are studying many approaches to prevent or delay Alzheimer's. Some focus on drugs, some on lifestyle or other changes. Let's look at the most promising interventions to date and what we know about them.

Physical activity has many health benefits, such as reducing falls, maintaining mobility and independence, and reducing the risk of chronic conditions like depression, diabetes, and high blood pressure. Based on research to date, there's not enough evidence to recommend exercise as a way to prevent Alzheimer's dementia or mild cognitive impairment (MCI), a condition of mild memory problems that often leads to Alzheimer's dementia.

Years of animal and human observational studies suggest the possible benefits of exercise for the brain. Some studies have shown that people who exercise have a lower risk of cognitive decline than those who don't. Exercise has also been associated with fewer Alzheimer's plaques and tangles in the brain and better performance on certain cognitive tests.

While clinical trials suggest that exercise may help delay or slow age-related cognitive decline, there is not enough evidence to conclude that it can prevent or slow MCI or Alzheimer's dementia. One study compared high-intensity aerobic exercise, such as walking or running on a treadmill, to low-intensity stretching and balance exercises in 65 volunteers with MCI and prediabetes. After 6 months, researchers found that the aerobic group had better executive function—the ability to plan and organize—than the stretching/balance group, but not better short-term memory.

Several other clinical trials are testing aerobic and nonaerobic exercise to see if they may help prevent or delay Alzheimer's dementia. Many questions remain to be answered: Can exercise or physical activity prevent age-related cognitive decline, MCI, or Alzheimer's dementia? If so, what types of physical activity are most beneficial? How much and how often should a person exercise? How does exercise affect the brains of people with no or mild symptoms?

Until scientists know more, experts encourage exercise for its many other benefits. Learn more about exercise and physical activity for older adults.

Controlling high blood pressure is known to reduce a person's risk for heart disease and stroke. The NASEM committee of experts concluded that managing blood pressure when it's high, particularly for middle-aged adults, also might help prevent or delay Alzheimer's dementia.

Many types of studies show a connection between high blood pressure, cerebrovascular disease (a disease of the blood vessels supplying the brain), and dementia. For example, it's common for people with Alzheimer's-related changes in the brain to also have signs of vascular damage in the brain, autopsy studies show. In addition, observational studies have found that high blood pressure in middle age, along with other cerebrovascular risk factors such as diabetes and smoking, increase the risk of developing dementia.

Clinical trials—the gold standard of medical proof—are underway to determine whether managing high blood pressure in individuals with hypertension can prevent Alzheimer's dementia or cognitive decline.

One large clinical trial—called SPRINT-MIND (Systolic Blood Pressure Intervention Trial–Memory and Cognition in Decreased Hypertension)—found that lowering systolic blood pressure (the top number) to less than 120 mmHg, compared to a target of less than 140 mmHg, did not significantly reduce the risk of dementia. Participants were adults age 50 and older who were at high risk of cardiovascular disease but had no history of stroke or diabetes.

However, the multiyear study did show that this intensive blood pressure lowering significantly reduced the risk of MCI, a common precursor of Alzheimer’s, in the participants. In addition, researchers found that it was safe for the brain.

The results of SPRINT-MIND provide further evidence of the connection between cardiovascular health and brain health. Further studies are needed to determine which people, at what age, might benefit most from particular blood pressure management approaches, and how these approaches affect the risk of dementia, including Alzheimer’s disease.

While research continues, experts recommend that people control high blood pressure to lower their risk of serious health problems, including heart disease and stroke. Learn more about ways to control your blood pressure.

Cognitive training involves structured activities designed to enhance memory, reasoning, and speed of processing. There is encouraging but inconclusive evidence that a specific, computer-based cognitive training may help delay or slow age-related cognitive decline. However, there is no evidence that it can prevent or delay Alzheimer's-related cognitive impairment.

Studies show that cognitive training can improve the type of cognition a person is trained in. For example, older adults who received 10 hours of practice designed to enhance their speed and accuracy in responding to pictures presented briefly on a computer screen ("speed of processing" training) got faster and better at this specific task and other tasks in which enhanced speed of processing is important. Similarly, older adults who received several hours of instruction on effective memory strategies showed improved memory when using those strategies. The important question is whether such training has long-term benefits or translates into improved performance on daily activities like driving and remembering to take medicine.

Some of the strongest evidence that this might be the case comes from the NIA-sponsored Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) trial. In this trial, healthy adults age 65 and older participated in 10 sessions of memory, reasoning, or speed-of-processing training with certified trainers during 5 to 6 weeks, with "booster sessions" made available to some participants 11 months and 3 years after initial training. The sessions improved participants' mental skills in the area in which they were trained (but not in other areas), and improvements persisted years after the training was completed. In addition, participants in all three groups reported that they could perform daily activities with greater independence as many as 10 years later, although there was no objective data to support this.

Findings from long-term observational studies—in which researchers observed behavior but did not influence or change it—also suggest that informal cognitively stimulating activities, such as reading or playing games, may lower risk of Alzheimer's-related cognitive impairment and dementia. For example, a study of nearly 2,000 cognitively normal adults 70 and older found that participating in games, crafts, computer use, and social activities for about 4 years was associated with a lower risk of MCI.

Scientists think that some of these activities may protect the brain by establishing "reserve," the brain's ability to operate effectively even when it is damaged or some brain function is disrupted. Another theory is that such activities may help the brain become more adaptable in some mental functions so it can compensate for declines in others. Scientists do not know if particular types of cognitive training—or elements of the training such as instruction or social interaction—work better than others, but many studies are ongoing.

People often wonder if a certain diet or specific foods can help prevent Alzheimer's disease. The recent NASEM review of research did not find enough evidence to recommend a certain diet to prevent cognitive decline or Alzheimer's. However, certain diets and healthy eating patterns have been associated with cognitive benefits. Studies of diets, such as the Mediterranean diet and the MIND diet—a combination of the Mediterranean and DASH (Dietary Approaches to Stop Hypertension) diets—are underway. Learn more about what we know about diet and the prevention of Alzheimer's disease.

For more information, read What Do We Know About Diet and Alzheimer's Prevention?

Researchers are exploring these and other interventions that may help prevent, delay, or slow Alzheimer's dementia or age-related cognitive decline. Other research targets include:

Alzheimer's disease is complex, and the best strategy to prevent or delay it may turn out to be a combination of measures. In the meantime, you can do many things that may keep your brain healthy and your body fit.

You also can help scientists learn more by volunteering to participate in research. Clinical trials and studies are looking for all kinds of people—healthy volunteers, cognitively normal participants with a family history of Alzheimer's, people with MCI, and people diagnosed with Alzheimer's disease or a related dementia.

To find study sites near you, contact NIA's Alzheimer's and related Dementias Education and Referral (ADEAR) Center at 1-800-438-4380 or email the ADEAR Center. Or, visit the Alzheimers.gov Clinical Trials Finder to search for trials and studies.

Alzheimer disease is the most common form of dementia. It affects your memory, thinking, and behavior. It often progresses to the point where it affects daily activities and functions.

Alzheimer disease most commonly affects older adults, but it can also affect people in their 30s or 40s. When Alzheimer disease occurs in someone under age 65, it is known as early-onset (or younger-onset) Alzheimer disease.

A very small number of people with Alzheimer disease have the early-onset form. Many of them are in their 40s and 50s when the disease takes hold.

Most types of early-onset Alzheimer disease are the same, but there are a few small distinctions:

Experts don't know what triggers the start of Alzheimer disease. They suspect that 2 proteins damage and kill nerve cells. Fragments of one protein, beta-amyloid, build up and are called plaques. Twisted fibers of another protein, tau, are called tangles. Almost everyone develops plaques and tangles as they age. But those with Alzheimer disease develop many, many more. At first, these plaques and tangles damage the memory areas of the brain. Over time, they affect more areas of the brain. Experts don't know why some people develop so many plaques and tangles, or how they spread and damage the brain.

Family history of the disease is the only known risk factor at this time.

For most people with early-onset Alzheimer disease, the symptoms closely mirror those of other forms of Alzheimer disease.

Early symptoms:

Later symptoms:

The current diagnosis of early-onset Alzheimer disease relies on detecting the signs of mental decline noted above. Your healthcare provider can then diagnose Alzheimer disease with a few tests.

First, your healthcare provider asks about your health history, and also does cognitive tests of memory, problem solving, and other mental skills. Depending on the results of the office-based cognitive testing, your provider may also request that you have more detailed testing done with a neuropsychologist. Your provider might also test your blood, urine, and spinal fluid. You may also need certain imaging test such as CT and MRI scans of your brain. These give your provider a closer look at brain tissue to show how much damage there is.

In the future, researchers hope that studies on biomarkers will allow experts to diagnose the disease more quickly. Biomarkers are proteins in the body, or other types of markers, that reliably indicate the progress of a disease.

Early-onset Alzheimer disease currently has no cure. But healthcare providers have been successful in helping people maintain their mental function, control behavior, and slow the progress of the disease.

Medicines are used to help people maintain mental function. They include:

Results have been mixed, but these medicines seem to help people with their symptoms for anywhere from a few months to a few years.

Other treatments that may play a role in slowing the progress of early-onset Alzheimer disease include physical activity, cardiovascular and diabetes treatments, antioxidants, and cognitive training. A number of studies are ongoing in this area, and researchers are learning new things about Alzheimer disease every day.

Experts don’t know how to prevent Alzheimer disease. Recently, some evidence showed that detecting the disease early can lead to better treatment options. It’s best to look for any of the early warning signs mentioned above and see your healthcare provider immediately if you notice any.

Early-onset Alzheimer disease can be a difficult disease to cope with. It helps to have a positive outlook and to stay as active and mentally engaged as possible.

It’s also important to realize that you are not alone. Rely on your friends and family as much as possible. Don’t be afraid to seek out a support group, if you feel that it might be helpful.

When the disease is still in its early stages, it's critical to think about the future. This can include financial planning, working with employers on current and potential job responsibilities, clarifying health insurance coverage, and getting all your important documents in order should your health take a turn for the worse.

The greatest known risk factor for Alzheimer’s and other dementias is increasing age, but these disorders are not a normal part of aging. While age increases risk, it is not a direct cause of Alzheimer's. Most individuals with the disease are 65 and older. After age 65, the risk of Alzheimer's doubles every five years. After age 85, the risk reaches nearly one-third.

Learn more: 10 Signs of Alzheimer's, Diagnosis, Visiting Your Doctor

Another strong risk factor is family history. Those who have a parent, brother or sister with Alzheimer’s are more likely to develop the disease. The risk increases if more than one family member has the illness. When diseases tend to run in families, either heredity (genetics), environmental factors, or both, may play a role. Learn More: What Does Alzheimer's Do to the Brain?

Scientists know genes are involved in Alzheimer’s. Two categories of genes influence whether a person develops a disease: risk genes and deterministic genes. Alzheimer's genes have been found in both categories. It is estimated that less than 1% of Alzheimer’s cases are caused by deterministic genes (genes that cause a disease, rather than increase the risk of developing a disease).

While age, family history and heredity are all risk factors we can’t change, research is beginning to reveal clues about other risk factors we may be able to influence through general lifestyle and wellness choices and effective management of other health conditions.

Heart-head connection: Some of the strongest evidence links brain health to heart health. This connection makes sense, because the brain is nourished by one of the body’s richest networks of blood vessels, and the heart is responsible for pumping blood through these blood vessels to the brain.

The risk of developing Alzheimer’s or vascular dementia appears to be increased by many conditions that damage the heart and blood vessels. These include heart disease, diabetes, stroke, high blood pressure and high cholesterol. Work with your doctor to monitor your heart health and treat any problems that arise.