Population-level interventions for the primary prevention of dementia: a complex evidence review.

Dementia risk reduction is a global public health priority. Existing primary prevention approaches have favored individual-level interventions, with a research and policy gap for population-level interventions. We conducted a complex, multi-stage, evidence review to identify empirical evidence on population-level interventions for each of the modifiable risk factors identified by the Lancet Commission on dementia (2020). Through a comprehensive series of targeted searches, we identified 4604 articles, of which 135 met our inclusion criteria. We synthesized evidence from multiple sources, including existing non-communicable disease prevention frameworks, and graded the consistency and comprehensiveness of evidence. We derived a population-level intervention framework for dementia risk reduction, containing 26 high- and moderate-confidence policy recommendations, supported by relevant information on effect sizes, sources of evidence, contextual information, and implementation guidance. This review provides policymakers with the evidence they need, in a useable format, to address this critical public health policy gap. Funding: SW is funded by a National Institute for Health and Care Research (NIHR) Doctoral Fellowship. WW and LF are part funded by the NIHR Applied Research Collaboration East of England. The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care.

Population-level interventions for the primary prevention of dementia: a complex evidence review.

BACKGROUND: Dementia is a leading, global public health challenge. Recent evidence supporting a decrease in age-specific incidence of dementia in high-income countries (HICs) suggests that risk reduction is possible through improved life-course public health. Despite this, efforts to date have been heavily focused on individual-level approaches, which are unlikely to significantly reduce dementia prevalence or inequalities in dementia. In order to inform policy, we identified the population-level interventions for dementia risk reduction with the strongest evidence base. METHODS: We did this complex, multistage, evidence review to summarise the empirical, interventional evidence for population-level interventions to reduce or control each of the 12 modifiable life-course risk factors for dementia identified by the Lancet commission. We conducted a series of structured searches of peer-reviewed and grey literature databases (eg, Medline, Trip database, Cochrane library, Campbell Collaboration, the WHO, and Google Scholar), in January, March, and June, 2023. Search terms related to risk factors, prevention, and population-level interventions, without language restrictions. We extracted evidence of effectiveness and key contextual information to aid consideration and implementation of interventions by policymakers. We performed a narrative synthesis and evidence grading, and we derived a population-level dementia risk reduction intervention framework, structured by intervention type. This study is registered with PROSPERO, ID:CRD42023396193. FINDINGS: We identified clear and consistent evidence for the effectiveness of 26 population-level interventions to reduce the prevalence of nine of the risk factors, of which 23 have been empirically evaluated in HICs, and 16 in low-income and middle-income countries. We identified interventions that acted through fiscal levers (n=5; eg, removing primary school fees), marketing or advertising levers (n=5; eg, plain packaging of tobacco products), availability levers (n=8; eg, cleaner fuel replacement programmes for cooking stoves), and legislative levers (n=8; eg, mandated provision of hearing protective equipment at noisy workplaces). We were not able to recommend any interventions for diabetes (other than indirectly through action on obesity and physical inactivity), depression, or social isolation. INTERPRETATION: This complex evidence review provides policymakers and public health professionals with an evidence-based framework to help develop and implement population-level approaches for dementia risk reduction that could significantly reduce the population's risk of dementia and reduce health inequalities. FUNDING: None.

Evaluation of clinical benefits of treatments for Alzheimer's disease.

The need for regulatory approval of new therapies for the treatment of Alzheimer's disease-a progressive neurodegenerative condition-has made the assessment of treatment efficacy an urgent priority for discussion and investigation in the field. In the first part of this Personal View, we summarise current views on what constitutes a clinically meaningful benefit from treatment for Alzheimer's disease, including the concept of a minimum treatment effect against which to compare trial outcomes and its limitations. Considering existing and divergent definitions of clinically meaningful change, we define this concept in the second part of the Personal View by proposing a new approach that consecutively considers whether a treatment benefit for Alzheimer's disease is noticeable, valuable, and worthwhile in the context of costs and risks. This approach could be a useful foundation from which the field can move forwards on this issue and address existing gaps in understanding.

Exploring English policymakers' attitudes towards dementia risk reduction: A qualitative study.

AIM: A growing evidence-base indicates that dementia occurrence can be changed. This has been linked to potentially modifiable risk factors. Risk reduction and primary prevention strategies are increasingly recognized as needing to include population-level policies to tackle the social and commercial determinants of health. How this knowledge can influence policymaking on dementia prevention is unknown. Understanding attitudes of policymakers is an important step in translating evidence into practice, helping to gauge system readiness for implementation, and potential barriers and enablers for influencing policy. The aim of this qualitative study is to explore the understanding of, and attitudes to, dementia risk reduction and population-level prevention strategies amongst English policymakers at national, regional, and local level. METHODS: Semi-structured interviews were undertaken with a range of dementia and prevention policymakers, with purposive sampling of national and local policymakers, including politicians, government officials, health system leaders, academics, and dementia charity directors. Analysis of interview transcripts was undertaken by thematic analysis. RESULTS: 14 policymakers were interviewed between November 2021 and February 2022. Three main themes were identified (1) Preventability of dementia, (2) Prevention approach, (3) Barriers and facilitators to improving the approach. DISCUSSION: Policymakers generally held dementia to be partially preventable. Policymakers recognised that both individual- and population-level approaches to primary prevention of dementia are required - with some policymakers perceiving that population-level approaches are under-utilised. Key barriers to implementing more population-level approaches were identified as the complexity and co-ordination required to effectively tackle upstream determinants of health.

What would a population-level approach to dementia risk reduction look like, and how would it work?

Dementia is a leading global public health challenge. Prevention approaches have traditionally focused on individual-level strategies. However, such approaches have limited potential, particularly for resource-constrained populations in which exposure to risk factors is greatest, and exposure to protective factors is lowest. A population-level approach to dementia risk reduction is therefore essential to meet the scale of the challenge and to tackle global inequalities in risk and incidence of disease. Such approaches can be highly cost effective. In this viewpoint article, we describe what such an approach should look like, barriers and facilitators to success, and how we should go about achieving it. We include 10 strategic goals to achieve population-level dementia risk reduction and protection enhancement, targeted at researchers, professionals, funders, science communicators, governments, businesses, and policy makers. If we are to significantly reduce the prevalence of dementia there must be increased emphasis on population-level approaches. HIGHLIGHTS: Dementia risk reduction is a global public health priority Population-level approaches change societal conditions to make them less conducive to dementia's modifiable risk factors, and increase exposure to protective factors. Urgent development of population-level approaches is required to reduce the prevalence of, and inequalities in, dementia Action is required from researchers, governments and business, funders, public health professionals, and science communicators.

The relevance of social and commercial determinants for neurological health.

A disconnect has developed over the past two decades between neurological and neuroscientific research, which have seen notable innovation and development, and our increasing understanding of the role of social and commercial determinants of health, including the health of the nervous system. Over the next two decades, grounding neurological research in public health and epidemiological principles can bring about a paradigm shift, away from reductionism, over-medicalisation, and health inequities towards neurological research that reduces inequalities and has true relevance to the populations it aims to serve. People who are involved in neurological and neuroscientific research and practice, as clinicians, researchers, publishers, and funders, can create change by being more aware of the social and commercial determinants of health, reprioritising research funding, and advocating for greater neurological health equity.

A systematic review of the cost-effectiveness of community and population interventions to reduce the modifiable risk factors for dementia.

Dementia is a leading global cause of morbidity and mortality. Evidence suggests that tackling modifiable lifecourse risk factors could prevent or delay a significant proportion of cases. Population- and community-based approaches change societal conditions such that everyone across a given community is more likely to live more healthily. We systematically reviewed economic studies of population- and community-based interventions to reduce modifiable lifecourse risk factors for dementia. We searched Medline, EMBASE, Web of Science, CINAHL, PsycInfo, Scopus, Econlit, ERIC, the British Education Index, and Google, on 03/03/2022. We included cost-effectiveness, cost-benefit, and cost-utility studies, provided that the direct outcome of the intervention was a modifiable risk factor for dementia, and was measured empirically. Quality appraisal was completed using the Consensus on Health Economic Criteria checklist. A narrative synthesis was performed. We included 45 studies, from 22,749 records identified. Included studies targeted smoking (n = 15), education (n = 10), physical inactivity (n = 9), obesity (n = 5), air pollution (n = 2), traumatic brain injury (n = 1), and multiple risk factors (n = 3). Intervention designs included changing the physical/food environment (n = 13), mass media programmes (n = 11), reducing financial barriers or increasing resources (n = 10), whole-community approaches (n = 6), and legislative change (n = 3). Overall, interventions were highly cost-effective and/or cost-saving, particularly those targeting smoking, educational attainment, and physical inactivity. Effects were observed in high- (e.g. USA and UK) and low- and middle-income (e.g. Mexico, Tanzania, Thailand) countries. Further research into the direct effects of targeting these risk factors on future dementia prevalence will have important economic, social and policy implications.

Systematic review of post-COVID-19 syndrome rehabilitation guidelines.

Introduction: Post-COVID-19 syndrome is associated with significant health and potential socioeconomic burden. Due to its novel nature, there is a lack of clarity over best practice for the rehabilitation of patients with ongoing or new symptoms following acute COVID-19 infection. We conducted a systematic review of clinical and service guidelines for post-COVID-19 syndrome rehabilitation. Methods: This review was registered on PROSPERO and is reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We included guidelines formally published or endorsed by a recognised professional body, covering rehabilitation of people with symptoms following resolution of acute COVID-19 infection. We searched Medline, Embase, PsycINFO, CINAHL, Web of Science, NHS Evidence, MedRxiv, PsyArXiv and Google for terms related to COVID-19, rehabilitation and guideline. Two reviewers independently screened articles for inclusion, data extracted and quality assessed using the AGREE II and AGREE-REX tools for clinical guidelines and the AGREE-HS tool for service guidelines. We included guidelines of sufficient quality in a narrative synthesis. Results: We identified 12 790 articles, of which 37 guidelines (19 clinical only, 7 service only and 11 combined clinical and service) were included. Guidelines covered a range of countries, rehabilitation types, populations and rehabilitation settings. Synthesis of clinical guidelines (n=4) was structured following the patient pathway, from identification, to assessment, treatment and discharge, with consideration of specific patient groups. Synthesis of service guidelines (n=8) was structured according to the Donabedian framework. Discussion: Though the available post-COVID-19 syndrome rehabilitation guidelines were generally of poor quality, there was a high degree of consensus regarding the breadth of symptoms, the need for holistic assessment by a broad multidisciplinary team and person-centred care. There was less clarity on management options, measuring outcomes and discharge criteria. PROSPERO registration number: CRD42021236049.

Do school closures and school reopenings affect community transmission of COVID-19? A systematic review of observational studies.

OBJECTIVES: To systematically reivew the observational evidence of the effect of school closures and school reopenings on SARS-CoV-2 community transmission. SETTING: Schools (including early years settings, primary schools and secondary schools). INTERVENTION: School closures and reopenings. OUTCOME MEASURE: Community transmission of SARS-CoV-2 (including any measure of community infections rate, hospital admissions or mortality attributed to COVID-19). METHODS: On 7 January 2021, we searched PubMed, Web of Science, Scopus, CINAHL, the WHO Global COVID-19 Research Database, ERIC, the British Education Index, the Australian Education Index and Google, searching title and abstracts for terms related to SARS-CoV-2 AND terms related to schools or non-pharmaceutical interventions (NPIs). We used the Cochrane Risk of Bias In Non-randomised Studies of Interventions tool to evaluate bias. RESULTS: We identified 7474 articles, of which 40 were included, with data from 150 countries. Of these, 32 studies assessed school closures and 11 examined reopenings. There was substantial heterogeneity between school closure studies, with half of the studies at lower risk of bias reporting reduced community transmission by up to 60% and half reporting null findings. The majority (n=3 out of 4) of school reopening studies at lower risk of bias reported no associated increases in transmission. CONCLUSIONS: School closure studies were at risk of confounding and collinearity from other non-pharmacological interventions implemented around the same time as school closures, and the effectiveness of closures remains uncertain. School reopenings, in areas of low transmission and with appropriate mitigation measures, were generally not accompanied by increasing community transmission. With such varied evidence on effectiveness, and the harmful effects, policymakers should take a measured approach before implementing school closures; and should look to reopen schools in times of low transmission, with appropriate mitigation measures.

Does playing a musical instrument reduce the incidence of cognitive impairment and dementia? A systematic review and meta-analysis.

Objectives: High levels of life course intellectually-stimulating activity are hypothesised to produce a cognitive reserve that mitigates against overt cognitive impairment in the face of neuropathology. Leisure-time musical instrument playing could be a viable source of that stimulation, but to date no systematic review has been undertaken to investigate the effect of musical instrument playing on the incidence of cognitive impairment and dementia.Methods: A systematic review and meta-analysis including any study with musical instrument playing as the exposure, and cognitive impairment and/or dementia as the outcome.Results: 1211 unduplicated articles were identified from literature searching, of which three articles were included: two cohort studies and one twin study. All studies were of good methodological quality, and reported large protective effects of musical instrument playing. The twin study reported that musicians were 64% less likely to develop mild cognitive impairment or dementia, after additionally adjusting for sex, education and physical activity. A meta-analysis of the cohort studies found a 59% reduction in the risk of developing dementia within the study follow up. The evidence base is limited by size, small sample sizes and the risk of reverse causality.Conclusion: The three identified studies that investigated the specific relationship of musical instrument playing and subsequent incidence of cognitive impairment and dementia all reported a large protective association. The results are encouraging but should be interpreted with caution. Larger, more focussed studies are required to further explore this association, with a particular need to consider the cumulative lifetime quantity of music playing.