August 21, 2015

expert reaction to number of people with dementia stabilising

Examining a number of previously published studied, an article in The Lancet Neurology journal has reported that the overall levels of dementia occurrence may be stabilising.

Mr Jeremy Hughes, Chief Executive of Alzheimer’s Society, said:

“While this study is welcome in showing that the percentage of people in particular age groups developing dementia could be getting smaller, the overall number of people with dementia is still set to increase as more people live into their 80s and 90s. With no cure, few effective treatments and an economic impact exceeding that of cancer or heart disease, dementia remains the most critical health and social care challenge facing the UK.

“This paper draws conclusions from the only suitable studies conducted in Europe – only five covering just four countries from over 15 years of research. This limited evidence may not indicate a continuing trend and we know that there are other risk factors for dementia, such as diabetes, that are increasing. We urgently need to improve the quality, coverage and regularity of research into the prevalence and numbers of people with dementia. Without this, we only have estimates to work on which can vary widely and can lead to poor health planning that can drastically affect our ability to make care better.

“The good news is that this research indicates improvements in healthcare, lifestyle, education and living standards in Western Europe are combining to play a role in reducing dementia prevalence. Today’s findings should energise the health system to do more to raise awareness and reduce our risk of dementia. Alzheimer’s Society will continue to lead in increasing public understanding of dementia and responsible risk management.”

Prof. Martin Prince, Professor of Epidemiological Psychiatry, King’s College London’s Institute of Psychiatry, Psychology & Neuroscience, said:

“From looking at this data, I would have slightly more guarded conclusions than those of the authors of the Lancet Neurology article. The evidence put forward to suggest declining prevalence in high income countries is fairly weak and inconsistent, or at best equivocal.

“Although much more research needs to be done to build a clearer picture, a plausible scenario, partly supported by evidence, is for age-specific prevalence to remain stable, despite declining incidence, because of an accompanying increase in survival duration for those that do develop dementia.

“The suggestion that dementia numbers could be stabilising in several West European countries is only supported by one of the studies included in the Lancet Neurology review (MRC-CFAS). This conclusion is therefore, in my view, somewhat speculative, and not reflective of the generality of the evidence. A wise approach for policymakers, until we have much clearer evidence to the contrary, is to assume that age-specific prevalence remains constant, and that, therefore, numbers will continue to increase in line with population ageing.”

Dr Matthew Norton, Head of Policy, Alzheimer’s Research UK, said:

“Although the proportion of older people with dementia has not increased according to these studies, age is the biggest known risk factor for dementia and with an ageing population in the UK, current estimates show the overall number of people with dementia is still projected to rise. Encouragingly, this research suggests that healthier behaviours may have helped reduce dementia risk in later-born generations. Current trends in risk factors such as obesity and diabetes mean we should not be complacent, but measures to help people adopt healthy lifestyles now could have a real impact on the numbers of people living with dementia in the future.

“We still need greater public awareness of the risk factors for dementia, and policymakers as well as charities have a key role to play in improving people’s understanding of what they can do to potentially reduce their risk. Evidence suggests that a balanced diet, regular exercise, not smoking or drinking to excess, and keeping blood pressure and cholesterol in check can all help to lower the risk of dementia.

“The risk factors for Alzheimer’s disease and other dementias are complex and not yet fully understood, but it’s likely that our risk is influenced by a mix of lifestyle and genetic factors. Currently there is no sure-fire way to prevent dementia, so it’s vital that we continue to invest in research into preventions, as well as better treatments and improved diagnosis for those cases that cannot be prevented.”

Dr Tara Spires-Jones, Reader and Chancellor’s Fellow, Centre for Cognitive and Neural Systems, University of Edinburgh, said:

“This review of five large epidemiological studies suggests that the percentage of the population with dementia is not growing and in the UK (both men and women) and in Spanish men, the percentage of the population affected may actually have fallen slightly over the last 20 years. While this is good news, we have to keep in mind that our population, particularly of people over 85 who are at greatest risk, is growing, so the number of people with dementia is increasing overall.

“In the UK over 820,000 people have dementia and worldwide the number is over 45 million.  While epidemiological studies such as this do not tell us anything about cause and effect, the slight decrease in the percentage of the population with dementia is likely due to the fact that we have learned much about the risk factors (vascular disease, heart disease, diabetes etc) that contribute to dementia and the protective factors (exercise, education, etc) and have been able to implement strategies to reduce risk and control chronic conditions.  This is great news for researchers, providing clues about how we should devise future effective treatment strategies.

“The bottom line is we need more research to learn to prevent and treat dementia, as it is a large problem for our ageing population.”

Dr Elizabeth Coulthard, Consultant Senior Lecturer in Dementia Neurology, University of Bristol, said:

“This is a robust assessment of epidemiological evidence suggesting that predicted dementia prevalence figures have previously been somewhat overblown. It is possible that factors such as nutrition and living conditions contribute to the stabilising prevalence. Nevertheless, the impact of dementia is still huge affecting around 7% of people over 65 and 40% of those over 80. So while this is positive news, it should not detract from the great efforts to develop treatments that may delay progression of dementia and improve quality of life for those affected by the disease.”

‘Dementia in western Europe: epidemiological evidence and implications for policy making’ by Wu et al. published in The Lancet Neurology on Friday 21^st August. 

Declared interests

Prof. Prince: I have received research grant funding from Wellcome Trust, DFID/ ESRC, US Alzheimer’s Association and European research Council. The Global Observatory at KCL has received support (for researcher salaries) from ADI, for the work that goes into the preparation for the World Alzheimer Report. We also received a contract from the UK Alzheimer Society for our work on the 2014 Update of the Dementia UK report.

Others: None declared