This page describes the major areas of research currently underway around the world to identify and develop strategies to prevent dementia.

Why is the endeavour to prevent dementia so important?  Currently, around 257,000 Australians have dementia.  The illness affects not only them but their families and friends as well.  By 2050, that is in just 40 years time, it is estimated there will be almost 1 million Australians living with dementia.  There is no cure for dementia and there is no treatment that can stop the illness from progressing.  The cost to people is obvious, but there is also an enormous cost to our health budget, which will continue to increase rapidly unless we can do something to prevent dementia.

Establishing dementia risk factors

Even though we have a lot of information about the risk factors for dementia, studies continue in order to clarify unresolved issues.  Ongoing studies are addressing for example:

• how large an effect a factor has on dementia risk
• the mechanisms by which a factor affects dementia risk
• the interactions between different risk factors
• the interaction between genetic and environmental risk factors
• the influence of a factor in different populations
• the life stage at which a risk factor is most important

For some proposed risk or protective factors, the jury is still out on whether they do influence dementia risk.  So larger, better designed studies are needed to establish whether or not these factors should be addressed in dementia prevention strategies.

Another important area of this work is literature reviews to establish what the published research says as a whole about particular risk or protective factors.  Many important review papers have been published in recent years that provide a much clearer picture than any individual study, which can have different findings to a similar study due to differences in methodology or the population studied.

Trials of dementia prevention strategies

To confirm whether a strategy or intervention does indeed reduce the incidence of a disease, randomised placebo controlled trials are conducted.  These involve large numbers of volunteers, half of whom receive the intervention and half a placebo, and testing to determine whether the intervention provides benefits above any placebo effect.  Such trials are not easy to design and conduct in relation to dementia, and to date there have been few of them and the results have been disappointing.

Because dementia mostly affects people in old age, but risk factors exert their influence over a long period of time before that, trials providing real answers as to whether an intervention can prevent dementia might have to be conducted over 30 or more years.  This is likely to be impractical.

Nevertheless, shorter duration trials are being conducted and do provide important information.  For example, studies of women who had taken hormone replacement therapy (HRT) at menopause generally show that they have a lower risk of developing dementia.  But a large intervention trial in women over 65 showed that those who were given HRT had an increased risk of developing dementia.  This demonstrates that there may be a window of time in which HRT is beneficial, but when taken in late life it may be detrimental to cognitive health.  It also demonstrates that HRT should not be taken in old age for the purpose of preventing dementia.

Trials of various dementia prevention strategies are continuing around the world and will add to the body of evidence about when and how we should act to reduce our dementia risk.

Pharmacological interventions

A great deal of research is underway around the world to develop drugs that can stop the disease processes that cause dementia, especially Alzheimer’s disease.  If the disease process can be identified early enough and such drugs can be developed, then a drug treatment could stop the disease before symptoms of dementia occur and hence prevent dementia.  Unfortunately, we may still be many years from achieving this.

Early diagnosis of dementia

Currently, dementia is diagnosed when symptoms of cognitive impairment and decline are obvious and are significantly impacting the person’s daily life.  If a treatment could be developed that stops the disease process that causes dementia, we would want to give treatment earlier than this to prevent any significant cognitive impairment.

Therefore, a great deal of research is underway investigating methods of diagnosing dementia before disabling symptoms are apparent.  Brain imaging techniques, biomarkers in the blood, cognitive tests and other measures are being investigated.