‘Substantial’ decline in rate of dementia over past two decades
Rates of dementia in the UK have fallen ‘substantially’ over the past 20 years, claims a major report that some GPs say raises questions over the Government’s drive to raise diagnosis rates.
The study, published in The Lancet today, indicates there are currently around 670,000 people with dementia in the UK – much lower than earlier estimates put at around 800,000.
The team from the Medical Research Council (MRC) carried out screening followed by diagnostic assessment for dementia in a sample of 7,635 people aged 65 years and older across three areas, namely Cambridgeshire, Newcastle and Nottingham, between 1989 and 1994.
From this, they estimated 664,000 people had dementia in 1991. Based on this figure and the effects of an ageing population, they predicted that 884,000 people – or 8.3% of the population – would be expected to have dementia in 2011.
But when the team carried out the same process in a further 7,796 people aged 65 and over from these areas between 2008 and 2011, they found the estimated prevalence in 2011 was much lower this time, at 670,000 or 6.5% of the population.
The results indicate around 200,000 fewer people than previously thought now have dementia, a relative reduction of 24%.
Co-investigator Professor Louise Robinson, professor of primary care and ageing at Newcastle University and a GP in the city, told Pulse that primary prevention strategies and improvements in care through QOF have been key to cutting the risk of dementia.
She said: ‘We suspect that the current improvements are largely due to sustained improvements in primary prevention nationally and better, more effective evidence-based care for chronic conditions like diabetes, which increase vascular risk, through primary care initiatives such as the Quality Outcomes Framework.’
The team’s research found that in contrast to the overall population, the prevalence of dementia increased among people living in care homes, from 56% to 70%, despite a fall in the proportion of elderly people in residential care.
Professor Robinson said: ‘A possible explanation is that the cohort of older people living in care homes are now more physically and cognitively impaired, and that community care and support packages are enabling less impaired people to continue living independently in the community.’
The main findings suggest other estimates of dementia prevalence may be too high – the Alzheimer’s Society currently estimates 800,000 people in the UK have dementia, based on a consensus from results of six studies including the 1991 estimates from the MRC.
But Professor Robinson said the findings did still support the Prime Minister’s Challenge on Dementia that aims to see dementia diagnosis rates boosted by 50% as the number of people receiving a formal diagnosis would be lower.
She said: ‘These findings do not change the need to have a national policy focus on improving the overall quality of dementia care currently provided in England in terms of numbers of people being accurately assessed, receiving a diagnosis and subsequently being provided with the necessary support and care to live well in the community.’
But Dr Martin Brunet, a GP in Surrey who campaigned against the introduction of this year’s enhanced service to routinely assess for dementia in certain groups, said the findings cast further doubt on the Government’s strategy.
He said: ‘There has long been a question mark over the data that the supposed low diagnosis rates of dementia are based upon – partly because the data are very old, and also because you have to make assumptions in order to conclude how many undiagnosed cases there are.
‘The target to improve diagnosis rates as an end in itself is highly questionable – as it can avoid questions such as whether people get post-diagnostic support and harms from over-diagnosis. It is even more questionable if it is based on unreliable data – we could be trying to diagnose more people with dementia than are actually out there.’
A Department of Health spokesperson said: ‘Whilst this research suggests that the number of people with dementia is lower than previously thought, it continues to affect a substantial and growing number of people. We cannot afford to halt the progress we have already made so far.
‘Dementia remains a priority for this government and the Prime Minister – we are committed to delivering improvements in dementia care and support, research and the creation of dementia-friendly communities.’
Dr Martin McShane, NHS England director for improving the quality of life for people with long term conditions, said: ‘This is a crucially important study which reveals new information about the real potential to reduce the numbers of people with dementia.
‘While the absolute numbers of people with dementia may be less than previously thought, there still remains significant variability across the country in diagnosis rates. NHS England will be reviewing the results, with experts in the field, along with other recent estimates of the prevalence of dementia.’