Findings from population studies of older people led by Professor Carol Brayne have provided descriptions to help clinicians and service providers understand prevalence, incidence and expected length of life lived with dementia, including at particular ages and in different settings.
These descriptions include those of ordinary people aged over ninety years old describing their lives, ability to function day to day and quality of life.
The Cognitive Function and Ageing Studies are large UK-based longitudinal multicentre studies looking at health and cognitive function in older people. CFAS homepage
The Cambridge City over-75s Cohort Study (CC75C) is a long-term follow-up study of a representative population-based sample of older people which started in 1985 from a survey of over 2,600 men and women aged 75 and above. CC75C homepage
Cam-CAN is a large-scale collaborative research project, launched in October 2010, with substantial funding from the Biotechnology and Biological Sciences Research Council (BBSRC). The Cam-CAN project is using epidemiological, behavioural, and neuroimaging data to understand how individuals can best retain cognitive abilities into old age. CamCan homepage
About Professor Carol Brayne and The Public Health of Ageing Research Unit.
Dementia and cognition
Our dementia and cognition studies have provided
- important evidence on the prediction of risk for development of future dementia, such as the doubling of risk with stroke, and also with poor quality of life
- contributions to large consortia which have highlighted the role of particular patterns of genes to clinically diagnosed Alzheimer’s Disease, including those associated with ageing changes such as inflammation and immune responses
- major impact on thinking about what it is that happens in the brain in the older population leading to the loss of cognitive and mental skills. This is clearly much more complicated than hoped, with research moving from the ‘tombstones’ of the pathologies associated with Alzheimer’s disease to investigation of small proteins, aggregation and their impact on brain cells with potential triggering of harmful cellular responses
- better understanding of the extent to which vascular pathologies are combined with the other neurodegenerative changes, providing a much clearer idea about the mixtures of pathologies that occur within any individual as they (we) age.
These neurobiological studies are conducted on our brain collections, from participants and their families who have been so marvellous in supporting our research – Professor Carol Brayne
Prevalence and prevention
The Cognitive Function and Ageing Study (Professor Carol Brayne, Dr Fiona Matthews) reported new dementia prevalence figures for the UK (Lancet 2013), showing that dementia in the population, when ageing is taken into account, is significantly lower than it was 20 years ago. This paper won the Neurology, Mental Health and Dementia category of the Royal College of GPs paper of the year 2014 and the studies have had direct impact on policy and modelling. The most likely explanation is higher education and better vascular health.
More broadly, our brain-based studies suggest:
- higher education protects from the clinical manifestation of disease
Our tracking of cognition and terminal decline analyses suggest:
- better recovery from impairment with higher education, social class and late life intellectual activity as well as a shorter phase of terminal decline
Seven risk factors for dementia
Modelling work undertaken by researchers within the NIHR Collaborative Leadership in Applied Research and Care East of England (CLAHRC EoE) updated the potential proportion of dementia in the population that might be prevented through tackling seven risk factors. This exercise led to an estimate of 30% of cases being associated with one or more of these risks (Lancet Neurology 2014).
Identifying research gaps
A public consultation on perceived research gaps in dementia, conducted by the CLAHRC EoE with the James Lind Alliance (JLA) and the Alzheimer’s Society, elicited 1563 responses. These were sifted and turned into questions, followed by a comprehensive check of the literature to establish true gaps. The top ten list that emerged is now contributing to funders’ calls in the UK; and the Alzheimer’s Society in Canada is planning to replicate our methods.
Reviewing evidence to underpin NICE guidance
Systematic reviewing and synthesis of existing evidence is a strength in many groups across the Institute. The Public Health, Ageing and the Brain group was commissioned by NICE to review the published evidence on midlife interventions to prevent dementia, frailty and disability in later life for the upcoming guidance, currently at the consultation stage. Dr Louise Lafortune is the lead for this work and also sits on the relevant NICE committee.
Healthy ageing, medications and polypharmacy
- We have found polypharmacy to be strongly associated with higher mortality.
- Specific medications can be associated with adverse outcomes. Many of the medications we take reduce the effectiveness of particular proteins involved in memory (anticholinergics). In particular we have investigated the cumulative anticholinergic score of the multiple medications that our older population are now encouraged to take for a variety of conditions.
We have found that the score which indicates a person is taking a lot of anticholinergics is associated with worse cognitive outcomes and higher mortality
Paradoxically we prescribe many medications which may reduce memory to counteract conditions which might also be harmful to cognition, such as hypertension. Those people with Alzheimer’s disease are often prescribed medications which are aimed at boosting acetylcholine through blocking the breakdown of acetylcholine. So there is a strong message here about prescribing for an individual, including assessment of polypharmacy and the nature of the medication for that person.
Screening for Dementia
The population health perspective allows us to consider the potential long term impact of screening of any kind. We have contributed to a range of screening debates and research studies over the years. In the dementia field we have used population data to assess the value of use of particular measures to identify ‘early’ dementia and intermediate conditions such as Mild Cognitive Impairment. This has been explored from a variety of angles, such as how different definitions for dementia work, proportions of the population that develop dementia, and how good the definitions are at identifying people who go on to develop dementia.
We can also assess how new measurements fit in, whether they are likely to identify more accurately those who progress or whether many false positives are likely. These findings have been published in many papers in a range of journals. Overviews and commentaries have been based on these findings and have made major contributions to the current debate on the value of screening for dementia given the current evidence base.
The UK Dementia Platform
The UK Dementias Platform (UKDP) is a radical new approach to dementias research, providing a translation pipeline from basic discovery through to early phase trials. It will combine more than 20 clinical and population cohorts representing 2M participants.
UKDP will create an optimal environment for basic discovery activities relevant to the clinical progression and human impact of dementia. UKDP is intended as a strategic and sustainable resource generating increasing scientific benefit over time, it will also deliver short and medium term benefits through the analysis of existing data, the enrichment of strategically selected cohorts, developing new ways of working with industry, and generating interest and further funding for dementias research generally.
The Institute will be involved in three UKDP work packages including: Biostatistical Methods and Support with MRC Biostatistical Unit (BSU), Ethical Legal and Social Implications (ELSI) with Public Health Genomics Foundation and Brain donation procedures in collaboration with Brains for Dementia Research (BDR) as well as its existing cohort studies: CFAS, CamCAN and EPIC Norfolk.