Earlier this year, the influential Alzheimer’s Disease International charity published its World Dementia Report 2014.
Dementia and Risk Reduction: An analysis of protective and modifiable factors critically examines the evidence for the existence of modifiable risk factors for dementia.
It focused on sets of potential modifiable risk factors in four key domains: developmental, psychological and psychosocial, lifestyle and cardiovascular conditions. The report makes recommendations to drive public health campaigns and disease prevention strategies.
Indeed, in that report the authors stated, “There is no evidence strong enough at this time to claim that lifestyle changes will prevent dementia on an individual basis.”
The report is littered all the way through it with qualifications on how, whilst a current focus on modifiable risk factors is justified by their potential to be targeted for prevention, “non-modifiable risk factors (eminently age, gender and genetic factors) are also very important.”
The full name of the Alzheimer’s Disease International, as its CEO Marc Wortmann (@marcwort) is keen to point out, is “Alzheimer’s Disease and Associated Disorders”.
This is clearly relevant as there are about a hundred different types of dementia, of which the dementia of the Alzheimer type happens to be the most prevalent. The media – and certain members of the medical profession – regularly like to conflate all dementias with Alzheimer’s disease, a phenomenon known as “Alzheimerisation”.
But it is hoped that accurate communication of risk of the dementias may play an important rôle in prevention, and in combatting stigma and discrimination. The big unresolved question is, of course, is how this emphasis exactly will help nearly a million currently living in the UK with dementia.
It is not thought that the prevalence of dementia in England is static. It is thought that it is falling.
As argued in a paper in the Lancet(Neurology), from the Medical Research Council Cognitive Function and Ageing Collaboration at the MRC Biostatistics Unit, Cambridge Institute of Public Health, Cambridge University, “This study provides compelling evidence of a reduction in the prevalence of dementia in the older population over two decades.” (1)
Indeed, the authors of that study indeed signpost what could be driving that reduction in their introduction.
“By contrast, factors that might decrease prevalence include successful primary prevention of heart disease, accounting for half the substantial decrease in vascular mortality, and increased early life education, which is associated with reduced risk of dementia.”
Prevention of dementia is likely to be big business.
In discussing recent data, Geeert Jan Biessels from the Department of Neurology, Utrecht, Netherlands mooted how identification of ‘at risk’ individuals could take place (2):
“Apart from timing of interventions, a question is whether prevention programmes should be population wide or target specific high-risk subgroups, as is now common in the prevention of cardiovascular disease. To target individuals at increased risk of Alzheimer’s disease, these individuals would need to be identified at a very early stage, well before the disease process commences.”
The NHS Health Check was launched in 2009 to assess and treat patients aged 40 to 74 for their risk of developing heart problems, diabetes, high blood pressure and kidney disease.
In July 2014, Prof Clare Gerada was reported as voicing serious concerns.
Gerada “backed the calls to end the routine checks, claiming they ‘devalued medicine’ and led to patients being needlessly worried as family doctors waste time on people who are not sick.”
‘You always find something that you can’t explain and then you do more tests,’ she said. ‘We’re constantly having to explain to patients that actually there’s nothing wrong.’
The Blackfriars Consensus Statement calls for new national focus to reduce risk of developing dementia.
Action to tackle smoking, drinking, sedentary behaviour and poor diet could reduce the risk of dementia in later life alongside other conditions such as heart disease, stroke and many cancers, according to the UK Health Forum and Public Health England in a joint consensus statement published on 20 May 2014.
The Blackfriars Consensus Statement argued that the scientific evidence on dementia risk reduction is evolving rapidly and is now sufficient to justify action to incorporate dementia risk reduction into health policies and to raise wider awareness about which factors can reduce the risk of developing dementia.
The Statement makes reference to a “precautionary principle”, which “requires that, even for those risk factors for which the evidence is less robust, we should recommend actions that could reasonably be presumed to reduce the risk of some types of dementia at least …”
This precautionary principle maximally allows for mission creep, of course, as rent seekers wish to establish new financial markets under the guise of prevention of medical disease.
According to one newspaper report today, “Middle-aged people will be screened by GPs for their risk of dementia and told how their “brain age” compares to their biological age, under new plans to “scare” people into adopting healthier lifestyles. It means a man of 40 could be told that he has the brain of a 60-year-old, and a significantly greater chance of diseases like Alzheimer’s, based on his weight, exercise habits, cholesterol levels and alcohol intake.”
The origins for this policy can be found in the computation of the ‘lifetime risk score’ for cardiovascular disease. Back in July 2013, there was a furore about the possibility of an army of patients being put on statin drugs to lower their risk from certain forms of cholesterol as a result of ‘JB3 guidance’. ‘Bad’ forms of cholesterol can cause heart attacks or stroke. The precise history of how the ‘Joint British Groups’ arrived at this is complicated, however.
But an influential article in the Heart journal from Joep Perk, Ian Graham, Guy De Backer from Sweden, Ireland and Belgium was pretty damning about this (3).
“Their ambition is to provide health workers, especially general practitioners, with answers to three key questions: Why should I start advising CVD risk reduction? When should I start? And what should I do?”
“However relevant these questions are, it should be noted that the proposed model has to our knowledge not been tested on a large scale. This remains the major shortcoming of all three sets of guidelines: in comparison with new drugs or technical equipment where extensive documentation is needed for approval, the methods for risk assessment or calculators remain remarkably poorly tested.”
“On the one hand wide application in clinical practice is advocated, while on the other hand little is yet known about feasibility, acceptance rate in a busy general practice, the understanding of the patient, or even the effect on individual behaviour. This is clearly an important challenge for future studies.”
So even if dementia is amenable to modifiable risk factors, how much of it exactly is amenable?
Sam Norton, Fiona E Matthews, Deborah E Barnes, Kristine Yaff and Carol Brayne in the Lancet Neurology earlier this year argued, on the basis of their data, “After accounting for non-independence between risk factors, around a third of Alzheimer’s diseases cases worldwide might be attributable to potentially modifiable risk factors. Alzheimer’s disease incidence might be reduced through improved access to education and use of effective methods targeted at reducing the prevalence of vascular risk factors (eg, physical inactivity, smoking, midlife hypertension, midlife obesity, and diabetes) and depression.” (4)
But even this estimate there might be inaccurate. To give them credit, the authors themselves conceded, “A strength of the single risk factor approach is that it highlights the potential for individual risk factors, but a major limitation is that the estimated combined population-attributable risk makes the untenable assumption of independence of the risk factors.”
I don’t blame Dr Charles Alessi for wanting to ‘make a difference’. Prevention is a core strand of dementia policy globally.
As Alessi himself writes, “I am excited by the opportunity we have to make a difference to people’s lives and I am determined that we will seize the moment and really capture the emerging evidence that dementia is not an inevitable part of ageing and in some cases can be prevented or its progression delayed. My role as lead for the prevention of dementia is to make this a reality for all of us.”
But the reputation of and trust in the medical profession are both vital.
It is essential that any policy of ‘risk calculators’ in England is rolled out by members of the medical profession with the utmost integrity and probity, especially since the plan is to pay GPs for every diagnosis of dementia made.
(1) Matthews FE, Arthur A, Barnes LE, Bond J, Jagger C, Robinson L, Brayne C; Medical Research Council Cognitive Function and Ageing Collaboration. A two-decade comparison of prevalence of dementia in individuals aged 65 years and older from three geographical areas of England: results of the Cognitive Function and Ageing Study I and II. Lancet. 2013 Oct 26;382(9902):1405-12. doi: 10.1016/S0140-6736(13)61570-6. Epub 2013 Jul 17.
(2) Biessels GJ. Capitalising on modifiable risk factors for Alzheimer’s disease. Lancet Neurol. 2014 Aug;13(8):752-3. doi: 10.1016/S1474-4422(14)70154-1.
(3) Perk J, Graham I, De Backer G. Prevention of cardiovascular disease: new guidelines, new tools, but challenges remain. Heart. 2014 May;100(9):675-7. doi: 10.1136/heartjnl-2014-305650. Epub 2014 Mar 25.
(4)Norton S, Matthews FE, Barnes DE, Yaffe K, Brayne C. Potential for primary prevention of Alzheimer’s disease: an analysis of population-based data.Lancet Neurol. 2014 Aug;13(8):788-94. doi: 10.1016/S1474-4422(14)70136-X.