Behind the headlines: can one in three dementia cases be prevented?

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By Kirsty Marais | Thursday 20 July 2017

‘How can I prevent dementia?’ is one of the most common questions we hear at Alzheimer’s Research UK. And no wonder: without treatments to affect the underlying diseases, it’s natural for people to look for ways to stave off the condition. It’s also hugely important for government, as action to help people reduce their dementia risk should mean fewer people developing the condition in future. So today’s headlines, suggesting that a third of dementia cases could be preventable, will doubtless be good news for many.

Understanding dementia risk is a complex task, and the researchers behind this report, which was presented today at the Alzheimer’s Association International Conference in London, had a big challenge on their hands. Let’s take a look at what they did.

Calculating risk

The headlines are based on a report from the Lancet Commission – a comprehensive piece of work part-funded by Alzheimer’s Research UK, which pulled together existing evidence on dementia prevention, diagnosis, treatment and care. The report summarises evidence from existing studies, and calculates how individual risk factors might affect the overall number of people living with dementia.

This is tricky task. Most of the evidence on dementia risk comes from observational studies: these look to see whether people with particular lifestyles or behaviours are more or less likely to develop the condition. While these studies are useful for spotting trends, they aren’t designed to tell us about cause and effect. But over time, multiple studies carried out in large groups of people have helped build a picture of the factors that seem to have the biggest impact – although this picture is not yet complete.

According to the researchers’ calculations, 65% of the risk for dementia comes from things we can’t change, such as our age, sex and genetic make-up. This review focuses on the things that we may be able to do something about, known as ‘modifiable risk factors’. The report names nine factors that may increase the risk of dementia:

  • hearing loss
  • low education
  • smoking
  • depression
  • lack of physical activity
  • social isolation
  • high blood pressure
  • obesity
  • diabetes

For each of these, the team calculated the percentage of dementia cases that could potentially be prevented if the risk factor could be eliminated.

The top three risk factors according to this calculation were hearing loss from mid-life, low education in early life, and smoking – with the researchers estimating that the number of dementia cases could be reduced by 9%, 8% and 5% respectively if these were removed. Overall, they estimate that if all nine of these risk factors could be completely removed, the number of people living with dementia could be reduced by 35%.

Putting information into practice

There’s no guarantee that someone who avoids all of these risk factors will definitely not develop dementia, but evidence suggests people may reduce their risk by doing so – and the calculation highlights what might help to reduce dementia prevalence across the population. There are some caveats: in an ideal world, no-one would have to worry about hearing loss, depression, or any of the other risk factors talked about in this report, but in reality it’s unlikely that we can completely eliminate all of these risks. But the report could be particularly helpful for policymakers to decide where to focus their efforts when developing prevention strategies.

It can be difficult to separate some of these risk factors. For example, we already know that obesity and lack of exercise raise the risk of type 2 diabetes, and that hearing loss can lead to isolation or depression. There is still debate about whether depression could in fact be an early symptom of dementia, rather than something that raises the risk of the condition.

Some of the research in the report is relatively new: the evidence suggesting hearing loss as a risk factor for dementia is still emerging, and we need more studies to get a fuller picture of how the two conditions are linked. Several theories have been offered: perhaps the extra mental effort needed to cope with hearing loss may cause the brain to be less resilient, or alternatively, the same biological mechanisms could be driving both hearing loss and dementia. We don’t yet know whether treating hearing loss early could help prevent dementia, so next we’ll need to see whether clinical trials can shed light on this question. Regardless, ensuring that hearing loss is treated appropriately is important for people’s quality of life.

While this report helps draw attention to the things we can do to reduce the risk of dementia, there’s still a need for better evidence – that’s why Alzheimer’s Research UK is investing substantially in this area through our Prevention and Risk Reduction Fund.

In the meantime, the best advice is that what’s good for your heart is good for your head: that means eating a balanced diet with plenty of fruit and vegetables, staying mentally and physically active, and keeping blood pressure, weight and cholesterol in check. For more information on how to reduce your risk of dementia, download our free booklet.


  1. Mel Oliver on 20th July 2017 at 6:03 pm

    Why is there no mention of the major role that the deficit of cholestol, gluthatione and testosterone ( in men) plays. Not to mention Statin drugs prescribed for high cholesterol. Why don’t doctors tell patients they need to be taken with co-enzyme Q10, or that they can use Red Rice Yeast Extract instead?

    If you look at the Fins who lead the world statistically, it was easy to find out why. In the 70s a doctor prescribed a nationwide low cholesterol drive to lower the high rates of cardiac disease. They cut the rates by 75%, but ended up with a dementia epidemic in its place.

    Cholesterol, especially has a major protective function, which is where coconut oil comes in. Not sure why the nutritional supplements are ignored, especially when it is very clear that the Western diet of saturated fat, processed foods and the use of yellow oils and spreads is causing the oxidation, inflammation and death of brain cells.

    The number of folks being diagnosed with Early Onset Dementia should be scaring the shite out of governments worldwide, but it appears no one yet has noticed.

    A Banting, LCHF or Ketogenic diet would definitely help folks, but very few medical folk recommend it. All together, it is about time that all the research is tied together and a comprehensive management plan put together.

    Our bodies and brains constantly renewing themselves, but neurogenesis is not my field of expertise and the fat/sugar metabolic exchange is complicated. However, my mother no longer has sugar cravings since being on coconut oil, which is good enough for me.

    Many carers with folks with dementia are not aware that they should be treating these cravings with FAT (healthy white fats like avocado, olive oil and omega fats found in fish and flaxseed), so they keep on allowing their LOs massive amounts of sugar that make the whole thing worse.

    The brain, body and all the processes involved are not simple, but cause and effect certainly is clear enough to me. I would love to continue my research and blogging, but my time is limited caring for maman and I need to sell Alzheimer fidget products in order to make extra moolla. I reckon that the medical field and research sees no financial benefits from using a holistic treatment like nutrition, so that is why the big bucks go to researching DRUGS that treat symptoms and not the cause. God help us all if one in 3 folks born in 2015 are going to develop dementia, the world of tomorrow is not one I want to be living in!

    • Melanie on 31st July 2017 at 5:32 pm

      I completely agree with you Mel Oliver, about taking a holistic approach to Alzheimer’s and most other modern illnesses but sadly the medical field think it is mumbo jumbo.

      The meddling with our food in the first place has triggered so much illness, in my opinion. People consider that they eat a healthy diet, but have we been so indoctrinated by marketing that we believe that yellow, man-made fats etc. are good for us? Along with the other chemical laden products we use for washing and cleaning, is it any wonder that the nation is getting sicker?

      My Mum has Alzheimer’s but only one of the triggers above applies to her.

  2. Marie Cadavieco on 21st July 2017 at 9:52 am

    They are looking for drugs to treat dementia, when half the population is taking drugs which hasten dementia! I though I was going senile until I stopped the Statins – because of agonising muscle pain! And suddenly recovered my memory!

  3. Michael Miles on 27th July 2017 at 6:27 pm

    Diabetes and obesity indicators in this report, point towards diet. Lack of physical activity can lead to social isolation, depression, hypertension and then taking up or continuing with smoking, so the whole lifestyle scenario is involved.
    This then leads to the need for a holistic approach to the prevention of Alzheimer’s which must be the aim of all health services.
    Too often they concentrate on treating the symptoms and not the cause as is suggested in the previous response. That is because the money is in the drug companies rather than in the macro solution that only Governments should lead, and the charities should pressurize in the direction of the funding and solutions.

  4. Verity Goodfellow on 28th July 2017 at 8:04 am

    If these findings are correct, can you please tell me why my healthy, well educated active husband, whose hearing only started to fail in his mid 70s, then developed dementia of mixed types? I’m sure there is no connection as have never heard it mentioned but his seemed to start shortly after receiving eye injections for age related macular degeneration. Surely a coincidence.

  5. Carole Waters on 28th July 2017 at 8:11 am

    My husband was diagnosed with young onset FTL dementia at the age of 53. He had never smoked, drank heavily, been overweight, suffered hearing loss , had always been physically fit, never had problems with his health and always ate a good, varied healthy diet. He was educated at a grammer school and has a high IQ. No other member of his family has suffered dementia. During his working life he was a chief engineer in the merchant navy until he came ashore and then worked in upper management, he has travelled extensively, his hobbies, of which he had many, his most popular were sub-aqua diving, hiking. Book reading (he could read up to two books a week), and large DIY projects including rebuilding our last home. I therefore find it extremely upsetting that experts keep pounding on about how bad life style could cause dementia, my husband proves that is not the case! I so desperately wish that a proven cause and cure could be made for this terrible disease but it appears to me that at the moment research is not making any head way into the real cause of this disease when they constantly blame individual lifestyle, they really need to look elsewhere.

    • Graham Edwards on 28th July 2017 at 9:03 am

      The nature of these conditions is that they creep up on us over a period of ten years or more unnoticed. This means that there has to be something amiss within ourselves, our internal meliux that is the cause.
      The research paper Nature Communications 6. (2015), indicates that the CSF ferritin level at the time of diagnosis gives a guide to the probable course of the disease.
      I agree with Dr Preston Estep in his book The Mindspan Diet, that one of the most important things that we can do, is to ensure that the level of iron stores in the form of ferritin in our bodies, is maintained at or near the recommended minimum, especially after the age of fifty years, which is the time when things seem to change.
      I recommend this book to everyone.

  6. Karen Shuter on 29th July 2017 at 8:08 am

    My mother was diagnosed with Alzheimers after a brain scan when she was 70. She died in May 2016 aged 79.
    She was an energetic sociable physically fit lady who kept fit by playing golf.
    She had originally been prescribed HRT from age 55 to 60 to alleviate menopausal symptoms but her doctor advised her to stop.
    Around the age of 65 she started suffering with depression and lost a lot of weight quickly.
    She refused to take antidepressants.
    Then the memory problems started to show.
    She was also craving sugar . She was not diabetic.
    My opinion is that she should never have been taken off HRT. I think that although there are many reasons we may develop Dementia one of them may be the depletion of oestrogen and testosterone as we age which may cause depression which affects the brain then affects memory.
    I have been using HRT since my first menopausal symptoms at age 50 and I am now 56. I fully intend to stay on HRT (patches) for the rest of my life . I feel that the benefits to me outweigh the possible side effects. If I get Cancer at least hopefully it will be treatable.

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Kirsty Marais

Team: Science news