Title: Going beyond the individual: developing the evidence base for whole population-based dementia prevention strategies, to inform local government policies
Funder: Department of Health and Social Care

Abstract: BackgroundDementia prevalence in the UK is forecasted to double to 1.6 million by 2040. Available treatments are minimally effective, but up to 40% of dementia is thought to be preventable. Optimisation of prevention strategies is vital. Current approaches tend towards 'high-risk approaches' that identify and encourage individuals at highest-risk of disease to change their lifestyle (e.g. NHS Health Checks). Rose's Prevention Paradox predicts that most cases of disease actually occur within the large proportion of the population at 'normal' or 'slightly-elevated' risk. We should therefore adopt more 'whole population-based approaches' (e.g. providing more, high-quality green spaces) to reduce risk across the spectrum rather than only target 'high-risk' individuals. AimsDevelop the evidence-base for whole population-based approaches to dementia prevention, to inform local government policy change.Research Projects What is known about whole population-based interventions to prevent dementia? A meta-review of existing systematic reviews. Apply a sampling frame of existing systematic reviews of dementia prevention interventions, and whole population-based prevention interventions more generally. Systematically summarise what is currently known about whole population-based interventions to prevent dementia. Retrospective cohort study to determine what proportion of incident cases of dementia would have been considered 'high-risk' in midlife. EPIC Norfolk is a population-representative cohort established in the 1990s (baseline n=30,000), with linked NHS data up to 2019. A retrospective cohort study using incident cases of dementia (n=3,187) and analysing what their baseline Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) score (dementia risk prediction score) would have been, will directly test the applicability of the Prevention Paradox to dementia. Apply the risk score to the current Health Survey for England dataset, to assess comparability of today's population risk with the EPIC-Norfolk baseline cohort. Policy mapping analysis of dementia prevention policies, using Stevenage, Hertfordshire as a case study. Identify and characterise existing international, national, regional, and local dementia prevention policies applied to the population of Stevenage, according to the type of prevention approach. Include explicit dementia prevention policies at all levels, and additionally include policies targeted at modifiable risk factors for dementia at the regional and local levels. Understanding policymakers' views and attitudes towards dementia prevention approaches, and what is required to shift policy towards whole population-based approaches. Present the findings of these projects to the key local policymakers and commissioners and then hold focus groups to explore their views and attitudes towards dementia prevention approaches, and how they have changed with the findings of projects 1-3. DisseminationI will summarise the findings of all projects into an evidence toolkit that will be shared with local government public health teams across the country. This toolkit will detail the evidence-base for, and policymakers' views of, whole population-based approaches to dementia prevention.Timelines for DeliveryI will start by ensuring data access and ethics are in place. I will then commence project 1,2 and 3, in that order, over the first 2 years of the proposal. The final year of the PhD will be focussed on delivering project 4 and producing the evidence toolkit.

Lay abstract: BackgroundIt is estimated that the number of people living with dementia in the UK will almost double by 2040 to around 1.6 million. We do not have effective treatments, however, up to 40% of future dementia is thought to be preventable for the next generation by reducing risk factors such as obesity, high blood pressure, smoking, and social isolation. It is vital that we have the best possible dementia prevention approaches in place.Current prevention policies tend to be 'high-risk approaches', which focus on identifying the small number of middle-aged people with lots of risk factors for dementia, and encouraging them to change their lifestyle (e.g. NHS Health Checks). However, because so many more people are at 'normal' levels of risk, it is likely that more cases of dementia will actually come from the normal-risk group than the high-risk group. This observation is called the 'Prevention Paradox' and it means that to prevent as many future cases of dementia as possible, we need more 'whole population-based approaches' (e.g. providing more, high-quality green spaces for people to exercise and socialise in), that aim to reduce everyone's risk, not just those at high-risk. We know that the Prevention Paradox applies to diseases like heart attacks and strokes, but we don't know if it applies to dementia. AimsDevelop the evidence to support whole population-based approaches to dementia prevention in local government, using Stevenage in Hertfordshire as a case study. Research Projects Summarise the existing international reviews of dementia prevention interventions, and 'whole population-based approaches' to prevention of dementia risk factors like obesity and depression, to understand what is already known about this issue. Test the applicability of the 'Prevention Paradox' to dementia by calculating what proportion of cases of dementia occur in people who would have been considered 'high-risk' or 'normal-risk' in midlife. EPIC Norfolk is a long-standing study, following participants (around 30,000 at the start) since the 1990s, including linking NHS data up to 2019. I will identify those participants who have received a diagnosis of dementia and look back at their data from their first evaluation by the EPIC Norfolk team in the early 1990s. By applying a risk score called 'Cardiovascular Risk Factors, Aging, and Incidence of Dementia' (CAIDE) which predicts risk of dementia over the next 20 years by looking at factors like age, years of education, weight, and blood pressure, I will calculate what proportion of people who went on to get dementia would have been considered 'normal-risk' and 'high-risk' in their midlife. If the Paradox is applicable, more cases will have occurred in people who would have been considered 'normal-risk' in their midlife. I will then apply the CAIDE score to today's population, using data from the Health Survey for England, to assess whether a similar proportion of people today are at normal-risk and high-risk compared to the EPIC-Norfolk study. Identify all current international, national, regional, and local dementia prevention policies (using Stevenage, Hertfordshire as the case study) and analyse whether they are high-risk or whole population-based approaches. Understand local policymakers' views and attitudes towards dementia prevention approaches by presenting the findings of these projects to them and holding several, small focus groups to explore whether they are now more in favour of whole population-based approaches, and what factors have influenced their views.DisseminationLocally, the public health team have committed to continuing to work with policymakers to shift the approach towards whole population-based policies. Externally, I will summarise this work into a 'toolkit' that will be shared with local government public health teams across the country so that they can take a similar approach.

Research activity codes: 3.1 PRIMARY PREVENTION INTERVENTIONS TO MODIFY BEHAVIOURS OR PROMOTE WELL-BEING
Health categories: NEUROLOGICAL