Dr Louise Allan is Dementia Lead for the British Geriatrics Society. In this interview she answers a wide range of questions on dementia - including the main risk factors, the main symptoms and possible ways of delaying the onset of symptoms.

Q. What are the main risk factors for dementia?

A: Smoking is a huge risk factor. Then there are other vascular risks – like high blood pressure, high cholesterol, obesity and diabetes. These are all risk factors for Alzheimer’s as well as vascular dementia.

Having less education is a recognised risk factor, whereas having more education can delay the onset of dementia.

There are also social risk factors, like social isolation and loneliness. Alcohol is a further risk factor, as too are some prescription medicines, like some antidepressants and some medicines for urinary incontinence, dizziness and sickness.

Head injuries are another risk factor and for some people, sadly, there’s a genetic or inherited risk factor.    

Q. How easy is it to detect dementia – what are the main symptoms?

A: It isn’t as easy as you may think. In its severe form it is much more obvious, for instance if people don’t know their family or where they are.

In its earliest phase we can’t always be sure. If the early symptoms are mild it may not be dementia. There could be another cause for the symptoms, like depression, a physical illness or delirium. And having a mild cognitive disorder doesn’t necessarily mean you have or will develop dementia. That’s why diagnosis can take quite a while, to allow time for other possible causes of someone’s symptoms to be discounted.

There’s also no universally agreed definition of dementia and in the US the term dementia has been replaced by ‘major neurocognitive disorder.’

The main symptoms of dementia are:

  • A progressive worsening of the symptoms over time (at least 6 months).
  • Affecting not only memory but other aspects of cognition, like planning, perception, motor skills and attention.
  • Leading to a change in someone’s ability to look after themselves and undertake the activities of daily living, compared with how they were before (this is important as what someone with learning difficulties can do might be very different from what a university professor can do, the point is to compare with what each person could do previously).

Memory problems are often seen as a major symptom but this tends to apply more to Alzheimer’s. If people have vascular dementia, for example, then memory problems tend to come later.

Q. Researchers have been exploring possible ways of delaying dementia. How strong is the evidence for the following, as possible ways of helping delay dementia:

Physical activity (including dance)

How much physical activity you do in mid life probably has a major effect. However, this makes research more difficult. To do a perfect trial you’d need to recruit people and follow their health for up to 40 years.

That means we have to rely on observational studies, which are less reliable. A long term intervention study might well show the same results but because this kind of research hasn’t been done we can’t be sure.

However there’s now so much evidence for the general health benefits of keeping physically active, and so few health risks, that it seems sensible to recommend physical activity.

How we get people to change their lifestyles and make and sustain a long term commitment to more physical activity is, of course a challenge. Many factors probably influence this, from formative childhood experiences to the physical environment people live and work in and a range of social issues.

Mental activity (like education, learning a new language, reading, and playing board games or card games)

Some evidence suggests that cognitive stimulation can be as effective as some medication in treating dementia.

In terms of prevention, the epidemiological evidence (from population studies) suggests the potential value of a rich environment – socially, educationally and physically. So dance can be particularly helpful. It provides cardiovascular exercise through physical activity. It helps with balance, reducing the risk of falls. It requires cognitive activity, to remember the sometimes complex dance steps. And it is a social activity. You typically dance with a partner in a social environment. It also helps combat depression.

As I’ll explain later, getting more education seems to delay the onset of dementia – and this seems to be a factor in its own right, even after accounting for other lifestyle choices individuals might make.

Being bilingual may also help. Some areas of the brain expand, depending on the type of mental activity. For instance the part of the brain that deals with spatial memory is expanded in taxi drivers. So changes in the brain as a result of different types of mental activity, like learning to become fluent in another language, mean the brain is probably better able to compensate when it is damaged, helping it to carry on functioning longer.

Social connections (for example with family and friends)

One practical example is patients in a falls group at my hospital. The participants seem to gain health benefits not only from the physical activity but also from being part of a group and the social interaction.

Conversely, if you’re alone at home and can’t get out or don’t have a network of family or friends this is a health risk factor.

It is too early to know if being part of an online community has health benefits


Observational studies suggest that having a well developed sense of spirituality can influence survival – although this could be part of a broader lifestyle and these other aspects could be influencing health.

Q. There’s a suggestion that keeping mentally active throughout our lives, for example through education and learning new skills, helps build a ‘cognitive reserve’ which enables our brains to keep working longer and delays the symptoms of dementia. How strong is the evidence for this?

A: There’s quite a lot of research supporting this, particularly research into the neuropathology of people who’ve had more education. Their brains seem to tolerate a higher level of damage without them experiencing the symptoms of dementia, compared with people who haven’t had as much education. The amount of education people have correlates independently with how early or late the symptoms of dementia appear, the more education the later the symptoms. This seems to support the idea that we can build a protective ‘cognitive reserve’ through mental activity.

Q. Research published in the Lancet earlier this year suggested dementia rates are falling in England i.e. the proportion of people aged 65 or over with dementia is falling – although this may be being masked by the fact that more people are living longer. Does this seem likely – and, if so, why do you think this is happening?

A: This is a reasonable assumption. There have been big changes since I first became a doctor. We used to see far more people with heart attacks. Because of action to reduce smoking and to recognise and address high blood pressure and cholesterol levels, we’re seeing fewer people with heart attacks. Older people have become healthier and this is likely to be having a knock on effect on dementia rates.

However, the current generation of older people usually led more active lives than the next generation of older people (people currently in middle age) is likely to have done and we’ll need to see what health implications this has.

Q. Trials of new drugs (medicines) to treat dementia have had limited success so far, often resulting in dangerous side effects. However, a new approach to targetting gamma secretase to treat Alzheimer’s seems to offer some hope. How long do you think it will be before reliable medicine to treat Alzheimer’s and other types of dementia will be available?

A: There’s probably no magic bullet. The brain is the most complex part of the human body. We have identified different types of dementia but each dementia is in some ways unique to the person who has it, so there’s unlikely to be a one size fits all medical solution.

Our brain needs a good environment to thrive in, including what is going on in the rest of your body, which can lead to dementia. There are also brain specific diseases like Alzheimer’s. So to treat dementia we’re likely to need a multi factorial approach.

Even if we could successfully treat Alzheimer’s there could still be other triggers for dementia, like problems with blood vessels. A range of other physical problems, for example being anaemic, can also increase the risk of dementia. If the problem is genetic you might find a way to correct this which would help people in that family. But this wouldn’t necessarily help people in general. Reliable medicine may emerge at some stage, suitable for treating a specific type of dementia, but this could still be a long way off and only help people with that particular type of dementia. And we’d need to be wary of possible side effects.

Q. Until effective medication is available, we presumably need to rely on finding ways to manage the symptoms of dementia - like falls, dizziness, digestion difficulties, urinary problems and sight problems. Has there been any progress made in recent years in ways of managing any of these symptoms?

A: There’s been gradual, incremental change over the last 13 - 14 years in the way we manage dementia. For example there used to be more use of anti psychotic drugs, whereas there’s now more use of cognitive stimulation.

However, there’s still very little evidence about preventing falls in dementia. There have only been three good trials and one didn’t show much improvement in fall prevention.

We know that multifactorial interventions are most effective. Exercise such as Tai Chi is good for preventing falls in older people generally – but we don’t yet have evidence that it helps prevent falls in people with dementia.

Q. What is delirium - and why does it matter as far as dementia is concerned?

A: If someone in your family has dementia but isn’t themselves this could be delirium. Conversely, not everyone who is confused has dementia. It could be delirium.

Delirium develops over a short period of time and is caused by acute brain failure. It could result in any of the following symptoms: being more confused, agitated (like plucking at bedclothes), hallucinations, poor attention, very quiet or drowsy, less able to care for themselves and loss of mobility.

Delirium is important for a number of reasons. It can affect anyone but particularly people over 65, with dementia, who are frail, have a sensory impairment or a severe illness or have had recent surgery or a fracture. It can also be caused by drug or alcohol consumption. It has poor health outcomes, including increased death rates and care home admissions. And some of the symptoms can be confused with dementia, resulting in it not being properly treated.

The good news is that delirium is preventable in about 40% of cases and, if properly diagnosed, it can be treated.

To reduce the risk of delirium make sure hearing aids are switched on and glasses are cleaned. Ensure a quiet sleeping area at night and good lighting while people are awake. If needed help ensure the person eats, drinks and moves around, and treat any pain or infection. Conversely, try to avoid constipation, catheters, restraint, sedation and bed, home or ward moves.

For me delirium is the ‘cognitive superbug’ so it is important that we know about it, how it differs from dementia and how to prevent and treat it.