Welcome to week 2 of my series on prevention, where I’m going to take what I consider to be the major health conditions and give you my take on the medical evidence for prevention. It’s been an exhausting weekend so far and a nice quiet day of gardening and blog writing awaits! My daughter qualified for a national swimming competition the finals of which were at the London Olympic swimming pool yesterday. 6 hours in the car and a few more by the poolside for a few minutes of racing is a tough ratio (that’s swimming!), but super proud of her for reaching the finals, and what a venue to compete at!
Today’s topic is one that is very close to home for me, and also very topical. I read in the news this week that legendary veteran broadcaster Jon Snow has been diagnosed with Alzheimer’s, and is navigating his way with this truly awful disease. As you may know from previous blogs, my mum is in a nursing home with Alzheimer’s. She is only 81, and has a fairly rapidly progressive form of the disease in that a couple of years ago you could be forgiven for not being able to tell she had it, yet is now unable to recognise me (or if she does she certainly doesn’t know my name) or identify everyday objects.
This cruel disease affects identity, families, relationships and independence, and I think is one many people fear more than any other. I certainly do.
Why dementia matters
Dementia is very common, becomes more common with age, and is becoming increasingly prevalent. Whenever I mention it to friends or patients, pretty much everyone will know someone in their own lives who has been affected by it. It is not just memory loss, although that may be one of the earliest features. It is often a very long illness, with an enormous impact on carers. The challenges my own dad went through caring for mum at home were extraordinary. I can only recall two times in my life that my dad had cried until her diagnosis, yet in the months before she went into a nursing home it was a daily occurrence. The thought of that scenario being played out in countless families the country over is both immensely sobering and tragic.
Brain health is therefore not a niche topic; it is central to healthy ageing. It does not just affect lifespan but is integral to healthspan, the years of good quality health we all hope for.
What we cannot control
Like cancer, there are some aspects of dementia we cannot control: our age, our genes and family history, previous brain injury in some cases, and some other diseases that can cause dementia despite good lifestyle. There may well also be a degree of luck, or biology we are yet to understand.
It’s also important to understand that dementia is not one single disease, but includes a number of conditions including: Alzheimer’s disease, vascular dementia, Lewy body dementia, frontotemporal dementia and mixed dementia, which have different mechanisms.
Prevention is therefore not simple.
What we can influence
The brain is not separate from the rest of the body. It depends on blood vessels, metabolism, sleep, hearing, movement, mood and social connection, and so what is good for the heart and blood vessels is usually good for the brain too. In 2024 I wrote a piece on dementia which I have linked to here but I think it is worth summarising what the current medical evidence suggests are the main areas where we can have some control in stacking the odds in our favour:
- blood pressure control, especially from midlife onwards
- not smoking
- diabetes prevention and good glucose control
- exercise: aerobic fitness and strength
- healthy weight and metabolic health
- sleep
- hearing loss assessment and hearing aids where needed
- treating depression and maintaining mental health
- social connection
- reducing excessive alcohol
- cognitive engagement / learning
- avoiding head injury where possible
- managing cholesterol and vascular risk
- treating atrial fibrillation where present, because of stroke risk
- vision assessment and treatment where needed
From my own experience, I would like to highlight hearing loss. My mum had been hard of hearing for years, but was reluctant to be assessed and resisted the idea for a long time. When she did eventually go, and was found to have significant hearing loss, she felt the test had been invalid because someone was distracting her. Who knows whether earlier treatment would have changed anything? I suspect not completely, because in most cases dementia reflects the interplay of many factors rather than one single cause. But I can’t help but wonder: what if?
This message applies to a great many health issues – prevention is better than cure and please get yourself checked out if you have concerns.
Screening / early detection: why it is complicated
In many respects this mirrors the cancer screening section last week. There is no simple equivalent of “one dementia screening test for everyone” that reliably tells us who will develop dementia and what to do about it. Indeed, screening asymptomatic people is more complicated. However, memory symptoms should certainly be assessed properly.
This is also an area where enhanced screening is developing quickly, including biomarkers, blood tests, PET scans and genetics. There is a ‘but’ here, and it’s a big one – testing creates questions: what does a positive result mean, what can be done, and could it cause anxiety? Then again, earlier diagnosis may become increasingly important as new disease modifying Alzheimer’s treatments become available, but also raise practical questions about access, selection and side effects.
I am a huge advocate of screening, but we shouldn’t lose sight of the fact that screening healthy people is still a high bar and one that should be managed carefully.
Key takeaways
Dementia is not one disease, and not all dementia is preventable.
Age and genetics matter, but they are not the whole story.
What is good for the heart is usually good for the brain.
Blood pressure, hearing, exercise, sleep, alcohol, mood, social connection and metabolic health all matter.
Memory symptoms should be assessed properly.
Prevention is not about blame or certainty. It is about stacking the odds in favour of a healthier brain.
For those who want to go deeper
I have previously written about the Lancet Commission’s work on modifiable dementia risk factors, please see the link above. They identified 14 modifiable risk factors and estimated that addressing them could prevent or delay up to around 45% of dementia cases globally. That is a compelling statistic, but is at a population-level, not an individual guarantee.
However two areas are worth briefly highlighting here. The first is genetics. The APOE gene, particularly the APOE4 variant, is associated with a higher risk of Alzheimer’s disease, although it is not deterministic: many people with APOE4 never develop dementia, and many people with dementia do not carry APOE4. Nevertheless used appropriately this can be very useful in some cases. A famous example of this is the actor Chris Hemsworth (of Thor fame) who discovered during his 2022 Disney+ docuseries Limitless that he carries two copies of the APOE4 gene variant—one from each parent. This genetic makeup substantially increases his risk of developing Alzheimer’s disease. Although clearly very fit (have you seen those muscles??!!) he has spoken about now optimising his lifestyle to reduce his risk.
The second is blood pressure, particularly in midlife. Dementia is not only about plaques and proteins in the brain; vascular health matters enormously. High blood pressure in midlife is associated with later cognitive decline and dementia risk, which is one reason I often say that what is good for the heart is usually good for the brain too. If you’ve not checked your own blood pressure for the last few months, do me a favour – get it checked this week, and if you don’t like the result, get some advice, whether from me or another health professional.
Looking ahead, this is exactly the sort of area I am interested in for future preventive health and healthspan work. In the not-too-distant future, I hope to gauge interest in a more formal preventive health and healthspan clinic. Brain health would be an important part of that: measuring risk earlier, tracking function over time, and helping people preserve movement, independence and quality of life for as long as possible.
A long one today, but before I sign off, this week’s research video looks at whether the way we move — our walking speed, balance, gait and activity patterns — might one day help detect early changes in brain health. The brain is not separate from the body; how we move, hear, sleep, connect and look after our blood vessels may all matter more than we once realised.