It was reported in The Lancet medical journal last month that the prevalence of dementia in the UK has fallen from around 850,000 to 670,000. This figure seems encouraging, but the risk is that it brings complacency to the world of dementia care.
Although it is impossible to say with certainty, there are probably two separate reasons for this reduction. Firstly, the often quoted higher figure was derived by consensus of opinion from experts rather than plain science. This was not an entirely inappropriate method of estimation, because
doing clinical studies to identify the true prevalence of dementia in a community is very difficult and the results are never 100% accurate. However, figures derived by heuristics are likely to be even less accurate and would probably tend to over-estimate the true figure.
The second probable reason is that the new figure compares current prevalence to a study using a similar method in 1994 and still finds a fall in dementia, even though the population has aged in that time. The only conclusion we can draw from this is that there has been a true fall in the rate of dementia. Which begs the question ‘Why?’
Scientists do not know really what causes dementia but it is emerging that risk factors for Alzheimer’s disease are the same as risk factors for heart disease: high blood pressure, smoking, obesity, lack of exercise, high cholesterol and diabetes. As these conditions are now better managed by a mix of lifestyle change and medication, it is not surprising that the rates of heart disease and dementia are both falling. Be warned though: you would probably need to make these changes now to reduce your risk of dementia in 20 years’ time! There is no quick fix.
The Blackfriars consensus statement, of which I was a co-signatory, stated last year that improving population heart health was an important public health measure to prevent dementia. The data reported in The Lancet last month strongly supports that message; individuals may be able to reduce the risk of getting dementia in later life by living healthily and caring for their medical conditions in middle age. Some experts have estimated that as much as 20% of cases of dementia are preventable by improving population health.
Furthermore, dementia costs the UK over £26 billion per year – more than cancer and heart disease combined. At the moment, less than 2% of the NHS budget is spent on disease prevention. The economic and clinical case for improved prevention strategies through better public health and education is compelling.
Falling prevalence is good news but my worry is that this message will mean dementia goes “off the radar” with politicians, health commissioners and providers, and with the public. There are over 650,000 people in the UK with dementia today and the number of people aged over 65 is set to increase from today’s figure of around 10 million to around 19 million by 2050, so the overall number of people with dementia is still set to rise significantly. It is worth bearing in mind that in the same month as The Lancet report, Alzheimer’s Disease International published a report on the global impact of dementia which shows convincing evidence that dementia is increasing across the world as a whole, mainly due to increases in developing nations.
Many people with dementia in the UK still never receive a diagnosis and many who are diagnosed receive inadequate aftercare. A good life with dementia is possible but to achieve this people need a proper diagnosis, good information, excellent medical care, psychological support, advocacy and support for their families and friends. To achieve this we need to avoid complacency in terms of current service provision, primary prevention and health service planning.
 ‘Dementia in western Europe: epidemiological evidence and implications for policy making’, Wu, Yu-Tzu et al., The Lancet Neurology, 20 Aug 2015 (DOI: http://dx.doi.org/10.1016/S1474-4422(15)00092-7)
Dr James Warner
Medical Director, Red & Yellow Care
Chair, Faculty of Old Age Psychiatry, RCPsych
National Professional Advisor, CQC