The relationship between diabetes and dementia is complicated. They are both conditions that affect many aspects of daily life, and when they occur together, they can make day-to-day tasks even more of a challenge. But with the right support, people can continue living well for many years.
Diabetes, in particular type 2 diabetes, can increase a person's risk of developing dementia. However, the risk is not the same for everyone and living with diabetes does not mean that you will develop dementia.
We also know that dementia can make managing diabetes more difficult due to changes in things like memory, concentration and diet.
On this page, we'll provide tips and information to help support someone living with dementia and diabetes, their carers, family members, and friends.
- How diabetes is linked to dementia
- Research on diabetes medications and brain health
- Reducing dementia risk
- Supporting someone with diabetes and dementia
- Using diabetes technology
- Get more support with dementia and diabetes
How diabetes is linked to dementia
Diabetes is a serious condition where a person’s blood sugar level is too high. It can happen when their body doesn't produce enough insulin or can't use it effectively. Or, when their body can't produce any insulin at all. And overtime, it can impact the nerves in the brain.
People with diabetes may also have other health factors such as high cholesterol, high blood pressure and may live with overweight. These can all add to the overall risk of developing dementia.
Remember, having diabetes doesn't mean someone will go on to develop dementia - but it does highlight the importance of looking after general health, managing blood sugar levels, and supporting overall wellbeing.
High blood sugar
High blood sugar, also called hyperglycaemia, can damage the small blood vessels that supply the nerves in the body - including those in the brain. When the brain doesn't receive enough blood, brain cells can die.
This can lead to problems with memory and may eventually lead to other serious problems like Alzheimer's disease or vascular dementia.
The term type 3 diabetes has been used unofficially to describe diabetes that affects people with Alzheimer's, and is not the same as type 3c which is caused by damage to the pancreas.
Low blood sugar
A hypo, also called hypoglycaemia, is when blood sugar levels, also called blood glucose level, drops too low. It can happen very quickly and can worsen dementia symptoms and recurrent hypos can even increase the risk of developing dementia, especially in people with diabetes.
Common symptoms of a hypo include feeling confused, being anxious or irritable, lack of concentration and feeling dizzy, so it may be difficult to tell if the person you care for is experiencing a hypo, as the symptoms could be similar to those of dementia.
A hypo needs to be treated quickly, so if in doubt, always check their blood sugar levels.
Infection
People with diabetes are more likely to develop infections such as urinary tract infections, chest infections or skin infections.
Infections can raise blood sugar levels and trigger something called delirium - a sudden change in thinking, behaviour or awareness. Delirium is treatable but needs urgent medical attention. The symptoms of delirium can sometimes be mistaken for those of dementia and can lead to a delay in treatment of infections.
Signs of delirium include:
- sudden confusion
- hallucinations
- not recognising familiar people
- becoming unusually drowsy
- agitation or aggression
- sudden behaviour change.
If you notice these symptoms, contact a GP urgently or seek emergency help.
Research on diabetes medications and brain health
This is an area of fast-growing research. Some diabetes medications may help protect the brain, but research is ongoing, and we still need more long-term studies.
GLP-1 receptor agonists (GLP-1 RAs)
GLP-1 agonists, such as semaglutide and liraglutide, are used in the management of type 2 diabetes to help lower blood sugar and support weight loss, and they have also been investigated for their potential to reduce the risk of dementia.
Clinical trials have shown that dulaglutide and liraglutide can improve brain function and may even reduce the build-up of certain proteins linked to Alzheimer's disease. However, as more research is still needed the medications are not yet licensed specifically for brain health.
Research on the type 2 diabetes drug metformin has also found possible benefits — it may help protect the brain by improving insulin sensitivity and reducing inflammation, which could potentially offer brain-health benefits and reduce dementia risk. But the evidence for metformin is mixed, and its effect on memory isn't yet clear.
What does this mean for you?
The person you care for shouldn't start, stop or change any medication because of dementia risk alone. But if you're worried or you think their treatment plan may need altering, speak to their diabetes specialist nurse, a GP or a consultant. They can talk you through the most suitable options and take their whole health into account.
Reducing dementia risk
- Managing blood sugar levels: Supporting the person you care for to find a glucose target and diabetes management plan that is appropriate for them, and working with their healthcare team to achieve the target will help reduce high and low glucose levels and protect their brain.
- Keeping active: Encourage them to move in a way that feels manageable. Even light activity helps improve blood flow to the brain.
- A healthy diet: Focus on a balanced, regular eating pattern where possible.
- Keeping blood pressure and cholesterol in range: Medication can help if lifestyle changes are difficult or not enough.
- Staying socially and mentally active: Meeting people, doing puzzles or reading, playing music, or learning something new can help keep their brain stimulated.
- Managing sleep, stress and emotional wellbeing: Poor sleep and ongoing stress can impact both diabetes management and brain health.
If you're worried about the memory or concentration of the person you care for, then speak to your GP. They may offer a blood test, medication review, or refer them for further assessment.
Supporting someone with diabetes and dementia
Looking after someone with both diabetes and dementia can be challenging. As dementia progresses, they may need more support with everyday diabetes management, from remembering medication to recognising when something isn't right.
Everyone's needs are different, and the amount of support someone needs will change over time. It's important to involve the person in decisions about their care wherever possible.
Common challenges include:
- forgetting to take medication
- taking medication more than once
- missing insulin injections
- difficulty reading blood sugar meters
- not recognising symptoms
- trouble preparing food or eating regularly
- changes in appetite or taste
- increased risk of dehydration
difficulty understanding when to seek help.
You may find it helpful to:
- Help them follow a regular routine for meals, medication and blood sugar checks.
- Watch for signs of high or low blood sugar, especially if they're no longer able to recognise or explain their symptoms.
- Attend diabetes or GP appointments together, so you can help ask questions and understand any changes to their treatment.
- Keep an up-to-date list of medications and make sure repeat prescriptions are ordered in time.
- Look out for sudden changes in behaviour or confusion, which could be caused by a hypo, high blood sugar, an infection or delirium and may need urgent medical attention.
- Speak to their diabetes team if you're finding their treatment difficult to manage.
Medication
Supporting someone to manage their medication can help make their diabetes routine safer and easier to follow. You could use a pill organiser, blister pack or dosette box, and set alarms, reminders or phone alerts to help them remember to take their medication.
If the medication routine feels complicated, ask their diabetes team whether it can be simplified. If there's a risk of accidental overdose, make sure medicines are stored safely.
And if they have difficulty swallowing tablets, speak to their GP or diabetes team about a referral to a speech and language therapist.
If the person you care for takes insulin, a diabetes specialist nurse can review their injection routine or suggest alternative types of insulin that may reduce the risk of hypos.
“The smart insulin pen is brilliant, as I can look at it and see that Donald’s has taken his dose and how long ago. Or that he hasn’t remembered to take it."
Read Caron’s experience of supporting her husband with diabetes and dementia.
Food and eating
The person you care for may sometimes forget to eat or lose interest in food altogether, which can cause their blood sugar levels to drop too low. At other times, they might eat more than they need because they can't remember whether they’ve already eaten.
It's also common to develop a stronger preference for very sweet or sugary foods, which can keep blood sugar levels high.
Practical tips:
- have small, frequent meals
- eat with other people where possible
- keep favourite foods available
- have finger foods if cutlery becomes difficult
- reduce distractions during meals.
You don't have to manage everything on your own. If you're caring for someone with diabetes and dementia, it's important to look after your own wellbeing too. Ask family or friends for support where possible, and speak to your GP or local carers' service if you're feeling overwhelmed.
Using diabetes technology
For some people, continuous glucose monitors (CGMs) can help reduce hypos or make blood sugar checks easier. But not everyone finds technology helpful, especially if memory or dexterity is impacted.
It's okay if a simpler routine is better, and the healthcare team looking after the person you care for can help decide what's right for them.
Get more support with dementia and diabetes
Dementia UK has a guide called 'Managing diabetes in person with dementia' you can download on its website – along with other information.
Alzeheimer’s UK has more information about the link between diabetes and dementia.
If you're struggling to manage your dementia and diabetes, or you're supporting someone who is, and need advice or someone to listen, we're here to support you. You can call our helpline on 0345 123 2399 or email helpline@diabetes.org.uk
You can also join our online forum and chat with others who might be facing similar challenges as you.
