What You Need to Know About Alzheimer’s Disease and Other Dementias

James Castro, Meg Seymour, PhD & Saman Asad Siddiqui, MD, MMSc

Alzheimer’s Disease is one of the leading causes of death for Americans ages 65 and older.1 It is the most common cause of dementia (as much as 60-80% of dementia cases are caused by Alzheimer’s Disease), and 11% of Americans ages 65 and older are estimated to have dementia caused by Alzheimer’s Disease.2

Many people who are diagnosed with Alzheimer’s disease actually have other forms of dementia, and as a result many studies that are described as being about Alzheimer’s Disease also included people with other types of dementia. This article will explain what Alzheimer’s Disease is, how it may differ from other types of dementia, who is most likely to develop either Alzheimer’s or other types of dementia and describe research on the risks and benefits of the medications prescribed as a treatment for Alzheimer’s Disease.

What is Dementia?

Whether caused by Alzheimer’s Disease or other causes, dementia usually worsens over time and will progress more quickly for some patients than others.  Early symptoms include having a hard time remembering recent events or conversations, as well as apathy and depression. When it becomes more advanced, patients show poor judgment, become disoriented, and lose the ability to take care of themselves.2

What is Alzheimer’s Disease? 

Alzheimer’s Disease is a disease that kills brain cells. Unfortunately, there is no cure for Alzheimer’s Disease. People with Alzheimer’s Disease have a buildup of a protein called “beta-amyloid” outside of their brain cells, as well as another protein called “tau” inside their brain cells. These changes in the brain begin years before anyone shows symptoms that their family and friends are likely to notice. There is no single test to diagnose Alzheimer’s Disease or other forms of dementia. Healthcare providers use several sources of information to diagnose any type of dementia, such as asking family members if they have noticed any changes in the patient, and giving the patient scientifically validated cognitive tests and memory tests. If healthcare providers suspect Alzheimer’s Disease, they may also use brain scans or lumbar punctures (also called spinal taps) to look for the beta-amyloid and tau proteins mentioned above.2 However, even a person with amyloid plaques and tau will not necessarily have Alzheimer’s disease.

If you or a loved one is experiencing cognitive changes, such as difficulty remembering recent events, it is recommended to speak to a healthcare provider in order to see if those changes are caused by Alzheimer’s Disease or dementia, caused by another medical disorder, or if they are of the level that is normal for a person’s age. For example, forgetting where your keys are or forgetting the names of celebrities or friends you haven’t seen in years is common for people over 65.

What Factors Increase Your Chances of Developing Dementia?

Scientists who study Alzheimer’s Disease and dementia have not identified one specific cause of the disease, but there are traits that mean you have a higher chance of developing Alzheimer’s Disease.

Age

Alzheimer’s Disease is not caused by age, but a person’s chance of being diagnosed with it increases with age. Although there are some rare exceptions, most people diagnosed with Alzheimer’s Disease are ages 65 and older. About 5% of Americans ages 65 to 74 have dementia, with Alzheimer’s Disease being a potential cause, compared with almost 14% of people ages 75 to 84, and almost 35% of people ages 85 and older.2

Sex

Two-thirds of Alzheimer’s Disease patients are postmenopausal women. One of the likely reasons is that women live longer than men.3 However, researchers believe that estrogen may help protect against brain disease, so menopause may increase the chances of developing Alzheimer’s Disease. The lower estrogen that comes with aging may increase the chances of developing Alzheimer’s and also may help explain why female patients show a faster rate of cognitive decline than male patients.3

Race

Black and Hispanic adults are more likely to develop Alzheimer’s Disease and related dementias than non-Hispanic Whites.4 Reasons might include possible genetic differences, differences in the prevalence of other diseases that make it more likely someone will develop dementia, lower socioeconomic status, and differences in environmental exposure to toxins.4,5

When people of color are newly diagnosed with dementia, they are often have a poorer memory than newly diagnosed White patients.4,6 For example, on average Hispanic dementia patients are diagnosed at a younger age,4 but also have experienced memory problems for a longer time before being diagnosed.6,7 Researchers believe that some racial differences in disease severity could be due to minority patients receiving medical help at a later time and thus receiving a delayed diagnosis. On the other hand, Black patients decline more slowly and live longer with a diagnosis.6 While Black and Hispanic patients are less likely to die from Alzheimer’s Disease than White patients, Asian, Native American, and White patients are equally as likely to die from the disease.4

Many patients with Alzheimer’s Disease and related dementias have sleep disturbances, especially Black and Hispanic patients.4 Depression is another common symptom that is especially common among Hispanic and African American patients.8 Hispanic patients are more likely than White patients to have psychotic symptoms, such as hallucinations.9

What Can You Do to Prevent Alzheimer’s and Dementia?

There are other traits that put you at higher risk of developing Alzheimer’s and dementia.  People who have an immediate family member with Alzheimer’s are more likely to develop it themselves.1 Someone who has had a traumatic brain injury is more likely to develop dementia as well.10

Environmental Exposures

However, there are changes you can make that will help prevent Alzheimer’s. Research has found that exposure to toxins in the environment may increase the chances of developing dementia.11 For example, a 2022 study of more than 2,200 U.S. women found that women who lived in areas with better air quality were less likely to experience cognitive decline.12 A different study that followed more than 7,000 older women for more than 8 years found that women who were exposed to more “fine particulate matter” were more likely to develop Alzheimer’s Disease and related dementias over the course of the study.5 “Fine particulate matter” refers to a type of pollution that’s a mix of solid particles and liquid. According to the Environmental Protection Agency, most fine particulate matter is emitted from factories or cars.13 Other studies on people around the world continue to see a connection between an increase in pollutants in the air and an increase in risk of dementia, Alzheimer’s, and Parkinson’s.11 Research has also suggested that exposure to lead could increase the chances of developing Alzheimer’s Disease.14 

Health Habits, other Health Issues, and Education

Most studies evaluating health habits are based on what people report, and that is not always accurate. However, several large studies show a clear impact of some of these behaviors on dementia. For example, a study published in 2022 based on the responses of  more than 378,000 people to the US Behavioral Risk Factor Surveillance System survey found that people with midlife obesity, physical inactivity, and low education were more likely to develop dementia. The people who participated in the study were women and men of different races and ethnicities.15 Since high blood pressure is often related to obesity and less educated people are more likely to smoke, it is not surprising that a different study found that high blood pressure and smoking increase the chance of developing dementia, including but not limited to Alzheimer’s disease.10,16 Anticholinergic drugs such as some allergy medications, antidepressants, and drugs for urinary incontinence, can also increase the likelihood of developing Alzheimer’s Disease.17  To learn more about medications that increase the risk of Alzheimer’s Disease (as well as other forms of dementia), you can read this article.

While some adults boast about how little sleep they need, a study published in 2021 found that people who sleep fewer hours when in their 50’s, 60’s, and 70’s are more likely to develop late-onset dementia.18 That study followed nearly 8000 patients over a 25-year period and found that those who slept less than 6 hours a night were 30% more likely to develop dementia. The authors suggested that this is because the brain is not as able to get the rest it needs or to clear the plaque associated with Alzheimer’s when people sleep less.

It has long been acknowledged that excessive alcohol consumption can cause symptoms of dementia, but there is now growing evidence that even moderate or light alcohol consumption over the years can harm brain health. This recent research has debunked earlier claims that moderate drinking protects against cognitive decline. Instead, studies now show that at any level of consumption, the more alcohol that people drink, the more likely they are to develop dementia.19 This makes sense since animal studies demonstrate how drinking alcohol can damage the brain.20 Earlier studies misclassified former alcoholics as non-drinkers21, thereby making moderate drinkers appear healthier when compared to non-drinkers.

For people hoping to prevent or delay dementia or memory problems, physical activity has been found to be helpful. Despite the popular belief that mental puzzles and games can also prevent or reduce dementia, studies have found that it is physical exercise rather than mental exercise that can be helpful.22,23

Some Foods can help prevent Dementia

The Mayo Clinic recommends a diet that combines the Mediterranean diet and the DASH diet, which aims to reduce high blood pressure. Called the “MIND diet,” this eating pattern emphasizes natural plant-based food and limits red meat, saturated fat, and sweets.24

Recent findings from a major study found that foods that cause inflammation may also increase the chances of developing dementia.25 Adults who eat foods with a higher Dietary Inflammatory Index (DII) score, which are typical of a Western diet rich in saturated fats and processed foods, are more likely to develop dementia, including Alzheimer’s disease. These results are consistent with the recommendation regarding the MIND diet, which combines the Mediterranean and DASH diets and is rich in anti-inflammatory components such as omega-3 fats, vitamins, and fiber. Both strategies work by increasing your consumption of foods that reduce inflammation. However, there are differences.  For example, some foods that contribute to inflammation are considered good for brain health and so are included in the MIND diet.

What Are the Treatment Options for Memory Problems Caused by Alzheimer’s Disease?

Many of the strategies included in the prevention section above can help slow the development of dementia symptoms, in addition to reducing the chances of developing dementia.

There is no cure for Alzheimer’s Disease, although there are several medications used to treat its symptoms or that are hoped to delay symptoms for a few months.

There are six medications that the FDA has approved for the treatment of Alzheimer’s Disease. Three are approved to treat mild to moderate Alzheimer’s Disease: donepezil (Aricept), galantamine (Razadyne), and rivastigmine (Exelon).

Two drugs are approved for people with moderate to severe Alzheimer’s Disease: memantine (Namenda) and a drug that combines memantine with donepezil (Namzaric). Although memantine may help those with moderate to severe Alzheimer’s Disease, it has not been shown to benefit patients whose disease is mild. To learn more about memantine and the research about it, you can read this article.

Common side effects of the five drugs mentioned above include nausea, vomiting, diarrhea, dizziness, and drowsiness.26 None of the five drugs stop the progression of Alzheimer’s Disease; they only provide temporary help by slightly improving cognitive and memory problems, usually for a short period of time.

Aduhelm was approved by the FDA in 2021 for mild cognitive impairment caused by Alzheimer’s Disease but was very controversial because there was no evidence that it improved memory, concentration, or other common symptoms.  Instead it was approved based on reducing the amyloid plaque on the brain that is considered a symptom of Alzheimer’s disease. Since it could cause brain swelling or brain bleeding it was not widely prescribed and was removed from the market in 2024. Lecanemab (brand name Lequembi) was approved in 2023 for mild cognitive impairment and early Alzheimer’s Disease because research showed that it could potentially delay a worsening of symptoms for a few months27, even though it also caused brain bleeds and brain swelling in many patients. In 2023, the FDA approved a similar drug, donanemab (brand name Kisunla) for treating early-stage Alzheimer’s Disease. The small benefits and substantial risks28,29 are similar for both drugs. The only information about these two drugs is based on short-term use, whereas the long-term benefits and risks are unknown, especially for patients taking “blood thinners” for atrial fibrillation or other cardiac problems.30 Because of the uncertain benefits and clear risks, patients who want Medicare to pay for these treatments must participate in patient registries that will collect additional information that is needed to better evaluate the risks and benefits.

Treatments for Agitation and Behavior Problems for Dementia Patients

Rexulti is the only medication that the FDA has approved to treat agitation in patients with dementia.  However, Rexulti is an antipsychotic medication, and like other antipsychotic medications (which are for people who “have lost touch with reality”), it can cause patients to have a stroke or die. Anti-psychotic drugs are especially dangerous for older patients.  For that reason, the FDA has issued its strongest warning, called a “black box warning” to notify people taking these anti-psychotic medications for any reason. To learn more about the risks of off-label antipsychotic medications, you can read this article.

Non-Medication Treatments 

There are some treatments for the psychological side effects of Alzheimer’s Disease that do not involve any medications. For example, music therapy has been shown to help reduce the depression that Alzheimer’s Disease patients can feel, and special lighting can help reduce the sleep problems that are common for those with the disease.2

Most surprising, it seems getting flu shots may help reduce the chances of developing Alzheimer’s disease and other dementia. For example, in a study of almost 2 million adults 65 and older that was published in 2022, the one million who had at least one flu shot during the next 4 years were 40% less likely to develop Alzheimer’s disease during that same four-year period, compared to similar patients who had not had any flu shots during that time. The authors suggested that this may be due to decreased inflammation as a result of improved immunity against the flu.31

The Bottom Line

While mild cognitive impairment can be cured when it is caused by medication, lack of sleep, and other causes, dementia is usually incurable. Some people are more likely to develop Alzheimer’s Disease and related dementia, such as women, Black and Hispanic people, those exposed to environmental toxins, and people with certain unhealthy habits. Available medical treatments have very modest benefits, if any.

If you are concerned that a loved one may have Alzheimer’s Disease or other types of dementia, please speak with a healthcare provider.

All articles are reviewed and approved by Dr. Diana Zuckerman and other senior staff.

The National Center for Health Research is a nonprofit, nonpartisan research, education and advocacy organization that analyzes and explains the latest medical research and speaks out on policies and programs. We do not accept funding from pharmaceutical companies or medical device manufacturers. Find out how you can support us here.

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