Dementia Life Expectancy for Older Adults

Dementia diagnosed later in life, particularly after age 70 or 80, often results in a reduced life expectancy due to age-related complications. By understanding these challenges, families and caregivers can focus on improving quality of life and addressing risk factors effectively.

How Age Affects Dementia Diagnosis 

While some memory changes come with age, dementia is not a normal part of aging. However, age is the strongest known risk factor.

This is due to changes in the brains of older adults. Around 3% of people aged 70 to 74 have dementia. This rises to 22% for those aged 85 to 89 and 33% for those over 90.

It’s normal to occasionally forget where your keys are or the name of someone you just met. However, forgetting essential job skills, language, or important memories is not part of normal aging. Symptoms of dementia include:

• Taking longer or needing help to complete basic tasks you always did yourself
• Forgetting the names of people, what objects are called, or what things are used for
• Misplacing your things, or getting lost yourself

Lifestyle factors linked to dementia in older adults include social isolation and the community environment.

Young-Onset Dementia

“Young-onset dementia” occurs in younger people, often due to genetic causes such as Alzheimer’s disease.

Additionally, it is more common that the cause of dementia is reversible in younger populations. Dementia can have metabolic, inflammatory, viral, or toxic causes. Sometimes, these conditions are treatable.

The initial symptoms of young-onset dementia are often more variable than those of late-onset dementia. Symptoms may include challenges with behavior, personality changes, or executive functioning challenges. The initial presentation may look more like a psychiatric illness than dementia. As a result, delays in diagnosis are common.

Risk Factors for Developing Dementia

While the exact causes of dementia aren’t fully understood, a mix of brain changes due to aging, genetics, lifestyle, and environment is believed to play roles. Here are some key risk factors:

• Age: Dementia typically occurs in individuals aged 65 and older. Age is the strongest risk factor for dementia.
• Family history: Dementia can run in families. If you have an immediate family member with dementia (e.g., a parent or sibling), you may be at a higher risk.
• Race and ethnicity: Black and Hispanic populations have higher rates of dementia than Caucasian individuals.
• Cardiovascular health: Poorly controlled high blood pressure and high cholesterol increase dementia risk.
• Smoking: Smoking increases the risk of dementia.
• Traumatic brain injury: A severe head injury or repeated head injuries can increase dementia risk.

It can take some time for symptoms to develop, too. It is theorized that the brain changes that lead to the symptoms of Alzheimer’s begin over a decade before any noticeable symptoms appear.

Life Expectancy for Different Types of Dementia

Life expectancy after a dementia diagnosis depends on factors such as age at diagnosis, dementia stage, overall health, and dementia type.

For example, individuals with cardiovascular disease may be more likely to develop dementia. Their cardiovascular disease may contribute to a shorter life expectancy.

Those diagnosed in late-stage dementia might face difficulties with swallowing or immune weakness. Spending more time in bed can lead to increased frailty, all contributing to a shorter life expectancy.

The type of dementia also impacts life expectancy. For example, vascular dementia increases the risk of heart disease and stroke, which may shorten life expectancy regardless of the stage.

The average life expectancy for several types of dementia is as follows:

These are simply averages. Someone with Alzheimer’s disease may live beyond 10 years if they are diagnosed at a younger age and in overall good health at diagnosis. However, someone diagnosed with dementia with Lewy bodies may be at an increased fall risk and have a shorter life expectancy.

What Factors Influence Longevity in Dementia Patients?

Managing your mental and physical health is crucial in early-stage dementia. This includes eating well, exercising, staying social, sleeping well, and practicing mindfulness.

Several factors determine longevity after diagnosis. Being a female, receiving an Alzheimer’s disease diagnosis vs. a different type of dementia, younger age at diagnosis, and an earlier stage of dementia all contribute positively to a longer lifespan.

Other factors can negatively affect life expectancy, such as:

• Older age
• Male gender
• Frailty
• Living alone
• Polypharmacy (taking five or more prescription medications)
• Certain dementia subtypes, such as Parkinson-Plus Syndrome (PPS) and dementia due to multiple etiologies (DMA)

Increased age and male gender are the most consistent factors for reduced life expectancy after diagnosis. While these risk factors are non-modifiable, you can still improve your quality of life.

Tips for Living Well

After a dementia diagnosis, care recommendations include:

• Providing holistic care that focuses on other health conditions the person may have along with dementia. Those with dementia may experience difficulty caring for themselves and managing their conditions. Addressing an individual’s mental health care and social support are essential, too.
• Managing the individual’s neuropsychiatric symptoms and recognizing that psychotropic drugs may be ineffective and harmful in those with dementia
• Caring for family members reduces the strain of caregiving and improves the patient’s quality of life

The extent to which a person with the disease can maintain their social relationships can also play a significant role. Patients should talk with their doctor or a psychologist for strategies to cope with social situations.

In addition, maintaining household responsibilities for as long as possible can help improve the quality of life and prevent an individual from being chair-bound. In later stages, a patient’s needs may change, and caregivers need to know how to care for themselves and their loved ones.

While there is no cure for dementia, maintaining a healthy lifestyle can delay the disease’s onset or prevent it from happening in some instances. Once diagnosed, several measures can provide whole-person dementia care.

Keep in mind, though, that many people live with severe disability due to their advancing disease. A 2020 study found that among more than 50,000 people ages 65 and over who were diagnosed with dementia, about 41% died within 10 years. The average survival time was a little over five years for females and four years for males.

How Lifestyle Changes Aid in Prevention

Diagnosis and onset may be partially preventable with lifestyle modification. A 2022 study examined five healthy lifestyle factors of several thousand men and women aged 65 and older. The five factors included:

• Diet
• Cognitive activities
• Physical activity
• Smoking
• Alcohol consumption

Those with four or five healthy lifestyle factors, as opposed to zero or one healthy lifestyle factor, had a longer life expectancy and fewer years of life with Alzheimer’s disease. Individuals who maintain a healthy lifestyle may have a 60% reduced rate of developing Alzheimer’s disease.

A 2020 report on dementia lists 12 preventable risk factors for dementia and estimates that 40% of dementia cases could be prevented if those risk factors are modified. Actions individuals can take to reduce dementia risk include the following:

• Managing hypertension (high blood pressure)
• Reducing hearing loss and using hearing aids as needed
• Reducing exposure to air pollution, including from second-hand smoke
• Preventing head injury
• Quitting smoking
• Maintaining a healthy weight and reducing obesity
• Managing diabetes
• Remaining physically active
• Getting quality sleep

Medications to treat high blood pressure are currently the only known medications that can help prevent dementia.

There have been many studies looking into the use of puzzles and other forms of “mental fitness” to help delay or prevent Alzheimer’s disease and dementia. A famous older study of nuns showed that the individuals most curious and engaged mentally in the world had a lower risk of developing Alzheimer’s disease and dementia.