For individuals living with dementia and their loved ones, dementia is an incredibly frightening and uncertain journey. One of the hardest parts is facing the unknown: What will happen next? How will the condition progress? How does dementia lead to death?
These questions weigh heavily on families and can leave them feeling powerless.
This article sheds light on what to expect as dementia advances, from how it impacts the body to how it leads to the final stages of life.
Note: While we hope to offer clarity and guidance, please remember that every person’s experience is unique. It’s essential to speak with a medical professional for advice tailored to your loved one’s situation.
How dementia affects the brain and body
Dementia is a progressive condition that kills brain cells, leading to problems with:
- Thought
- Memory
- Understanding
- Communication
- Bodily functions (like breathing, circulation, and digestion)
It gradually affects the blood supply to part of the brain, ultimately becoming a terminal illness.
In very rare cases, symptoms can worsen dramatically over weeks or months – a pattern known as rapidly progressive dementia (RPD), which may be triggered by underlying neurological conditions.
Dementia damages different areas of the brain depending on its type and stage. Alzheimer’s disease, for example, impacts the hippocampus and entorhinal cortex (areas crucial for memory formation and recall).
Other common types of dementia include the following:
- Vascular dementia develops from reduced blood flow to the brain, often due to strokes or small vessel disease. It affects the brain’s ability to think, plan, and remember. People with vascular dementia may experience confusion, trouble with concentration, and difficulty making decisions.
- Lewy body dementia happens when abnormal protein deposits (Lewy bodies) form in the brain, impacting memory, movement, and mood. It leads to visual hallucinations, Parkinson’s-like symptoms, and fluctuating alertness.
- Frontotemporal dementia occurs when the frontal and temporal lobes of the brain are damaged by the buildup of abnormal proteins. It can lead to impulsive behaviour, social withdrawal, and difficulty with speech.
As the disease progresses, some individuals may become more irritable, anxious, or physically aggressive – behaviours often seen in what we describe as the dementia aggression stage, when changes in the brain affect emotional control and communication.
The average life expectancy of people diagnosed with dementia ranges from:
- 9 years at age 60
- 4.5 years at age 85
Find out more about the seven stages of Alzheimer’s disease.
Common causes of death in people with dementia
Why is dementia fatal? The truth is that dementia causes death in different ways. Understanding the common causes of death in dementia can help you prepare for what lies ahead and provide the right support to your loved ones when the time comes.
Here are some of the common causes of death in people with dementia and what to expect.
Aspiration and infections
People with dementia are more prone to pneumonia and respiratory infections due to their weakened immunity and trouble clearing the lungs. The brain controls our ability to coordinate swallowing and breathing. In the end stages of dementia, this skill is lost.
As a result, your loved one may inhale food or fluids which can lead to choking and chest infections called aspiration pneumonias. These can be life-threatening.
Studies also show pneumonia as the leading cause of death in people with dementia:
- Autopsy studies consistently report pneumonia as the leading cause of death (38% – 66%) in people with dementia.
- Death certificate studies identify pneumonia as a leading underlying cause of death in people with dementia.
- A meta-analysis found that people with dementia had higher odds of dying from pneumonia compared with people without dementia.
Early recognition and prompt medical care are key to managing symptoms and ensuring comfort.
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Complications from coexisting conditions
Many people with dementia also have other chronic conditions:
- 44% have hypertension.
- 17% – 20% have diabetes, stroke, transient ischaemic attack (TIA), coronary heart disease (CHD), or depression.
- 9% – 11% have Parkinsonism, chronic obstructive pulmonary disease, or asthma.
Dementia makes it harder to manage overall health, increasing the likelihood of complications from these conditions. For example, a person with dementia might forget to take medication for high blood pressure.
You can help loved ones in this situation by setting up medication reminders, organising medications in pillboxes, or using alarms to prompt daily tasks.
It’s also essential to ensure they receive the right professional care, like regular check-ups with doctors or visits from at-home carers. Having a team of healthcare professionals can make a world of difference in maintaining their well-being and ensuring comfort towards the final stages of life.
Nutritional problems and dehydration
In the later stages of dementia, people struggle to eat well and stay healthy. They may find buying and preparing meals a challenge, lose their appetite, and lose weight. Towards the end of the illness, they also lose muscle control, meaning they’re unable to chew and swallow.
Without enough food and fluids, the body weakens rapidly. Malnutrition and dehydration compromise the immune system, increasing the risk of infections, triggering organ failure, and causing extreme frailty. As these complications progress, they can ultimately lead to death.
To help, caregivers can offer soft foods, prepare meals, and encourage regular drinking. In later stages, a healthcare team or carer can monitor nutrition, suggest supplements, and focus on keeping the person comfortable and cared for with dignity.
Falls and related injuries
Dementia can affect people’s ability to live safely and independently. Mobility, stability, and spatial awareness can all be impaired, leading to an increased danger of falls and dangerous fractures.
Studies also show that older people with dementia experience eight times more incident falls than those without dementia.
Simple changes like clearing trip hazards, adding grab bars, and improving lighting can make the home much safer. With extra support and supervision during daily routines, caregivers can help protect loved ones from falls while supporting their independence.
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Continence and self-care
Toileting and managing personal hygiene becomes difficult as dementia develops. In the late stages, many people lose control of their bladder and their bowels. This increases the risk of urine infections, which can be deadly for dementia patients with a weakened immune system.
There are a few ways to help a loved one suffering with incontinence. Creating a regular toileting routine, using incontinence products, and keeping the skin clean and healthy to prevent irritation or infection are a few examples.
As needs increase, bringing in professional or at-home carers can also help. These professionals offer comfort, dignity, and quality of life during this difficult stage.
Find out more about using private carers.
Skin ulcers
Dementia leads to a progressive decline in physical function. The muscles become stiff and your loved one will need help moving and managing daily living. This immobility can increase the risk of pressure sores and ulcers. Not only are these sores painful, but they can also lead to health risks when infected.
This study found that of 135 patients with advanced dementia, 47.4% had one or more pressure ulcers.
Repositioning your loved one regularly helps relieve pressure on vulnerable areas, especially when sitting or lying down for long periods. Pressure-relieving cushions make a big difference in preventing sores from developing.
If pressure sores do occur, it’s crucial to clean the area gently and apply the right treatments to prevent infection. Consult a healthcare professional to find out more about how to manage sores and ensure your loved one is as comfortable as possible.
Advanced dementia and system failure
In the final stages of dementia, as brain damage becomes extensive, the neurological control of vital bodily systems begins to fail. This can affect:
- Heart function and circulation
- Breathing patterns
- Temperature regulation
- Immune system response
This widespread system failure ultimately leads to death in the terminal phase of dementia.
Your loved one may spend most of their time resting. As the body weakens, the risk of infections, blood clots, and breathing difficulties grows. At this stage, the focus shifts to comfort and quality of life.
Gentle repositioning, pain relief, and a calm, soothing environment can help. Bringing in end-of-life care (like hospice or palliative care professionals) also keeps your loved one as comfortable and peaceful as possible.
Finding support and understanding in the final stages of dementia
While the experience can feel isolating, support is available. Nearly one million people were living with dementia in 2024, and that number is expected to reach 1.4 million by 2040. With the right support and care in place, you can help your loved one live well with dementia and die with dignity. Explore our specialist dementia care services.
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Jane has over 20 years’ experience as a health writer and TV presenter. Jane writes on a wide variety of clinical and care topics – from explaining the latest studies and research to unpacking conditions and discussing treatment options. Jane holds a MBBS degree from Imperial College, London and spent seven years working in the NHS.
