Dementia and why we need to prevent it

In an open letter to the leaders of the three main political parties this week, a group of leading medical groups and charities state that people with long-term progressive conditions such as dementia have been “cut adrift”. Dr Iain Lang, from from the University of Exeter Medical School, reviews what we know about dementia, and argues that it is prevention rather than cure that should become the focus of policy makers and health professionals alike.

Photo credit: Pauline Bailey

Around the world, national populations are getting older and because dementia is so strongly linked to age (the older you are, the more likely you are to suffer from dementia) the proportion of the population with dementia is going to grow.

The term dementia is a catch-all for a range of conditions. The most common forms are Alzheimer’s disease and vascular dementia but there are many others and it is now thought likely that people often have more than one form concurrently (mixed dementia).

What is generally thought most significant is the loss of function and changes in behaviour that dementia can bring; things like loss of day-to-day memory, disorientation, and problems with concentrating, particularly when these begin to affect daily life.

In the UK more than 1% of the population is thought to have dementia and that proportion is set to rise. The cost of dementia is already estimated at over £23 billion per year (Alzheimer’s Society figures) and is likely to keep rising as more and more people are identified with dementia.

Some good news

There have been a number of recent studies suggesting that populations of older people in different parts of the world have less dementia than would have been expected based on past figures.

The most high-profile figures in the UK relate to findings from the Cognitive Function and Ageing Study (CFAS). In that study, researchers visited a number of areas in England and Wales in 1991 and again in 2011.

Based on the 1991 results the researchers estimated that by 2011 there would be 884,000 people aged 65 and over with dementia in the UK. In fact, based on the 2011 results they estimated there were only 670,000 people with dementia, 24% less.

Studies from other countries, including the US, Sweden, and the Netherlands, have also found reductions in the estimated numbers of people with dementia.

A possible reason for these changes is improvements in public health including:

  • reductions in the numbers of people who smoke
  • improved treatment for high blood pressure and cholesterol
  • rising levels of education

All of the above are known to reduce risk of dementia. However, we are now aware of other, more harmful, changes in population health and health behaviours that may reverse these improvements.

Some not so good news

People are eating poorer diets and are less physically active and this has already led to higher levels of obesity and growing numbers of people with diabetes: all known to increase risk of dementia.

It may well be that the improvements we have seen in the past are offset or even overshadowed by the problems we are now facing.

Greater attention has been paid to the problems posed by dementia in recent years, in no small part due to David Cameron’s interest. The UK hosted the G8 Dementia Summit in 2014 and appointed the World Dementia Envoy, Denis Gillings, to champion dementia research and development.

Much of the push in dementia research has been towards identifying a cure or disease-modifying treatment (there are currently none) and Gillings has identified a need for “accurate diagnosis, effective treatment and improved care and support.”

One important element absent both from this comment and from much current policy is a focus on dementia prevention. A joint statement this year by Public Health England and the UK Health Forum, known as the Blackfriars Consensus, has called for a preventive approach focused on reducing risks for dementia in the population. The statement highlights the growing understanding of how to reduce risk in the population so that fewer people develop dementia.

As well as the things mentioned above: physical inactivity, tobacco and alcohol use, and poor diet, the statement identifies a number of modifiable risk factors that influence dementia more directly including:

  • social isolation
  • untreated infection
  • depression
  • substance abuse
  • head injuries.

Hope for the future

The fact that estimated dementia numbers have been observed to fall in several countries offers hope that levels of dementia in whole populations levels are amenable to intervention and reduction.

There is an urgent need for policy makers and healthcare commissioners at all levels: local, regional, national, and international, to ensure they have clear policies in place to reduce the risks of dementia in the populations for which they are responsible.

Right now we are firefighting, dealing with the consequences of dementia when it occurs. It is very important that we do so but alongside that we need to be acting to implement effective strategies to prevent the growth in numbers of people with dementia.

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