Attitudes and Preferences Towards Screening for Dementia with a Focus on Ethnic Minority and Low Socio-Economic Groups: A Systematic Review of Research Studies Written in the English Language

INTRODUCTION

Dementia is a progressive syndrome, with many underlying potential causes, characterized by cognitive deficits leading to functional impairment. 1 Globally, approximately 55 million people were estimated to be living with dementia in 2019, 2 with numbers predicted to increase to 139 million by 2050. In addition to increasing age, the identification of modifiable risk factors for dementia, including smoking and excessive alcohol consumption, levels of physical, cognitive and social activity, hearing loss and preventing and managing chronic conditions such as diabetes and hypertension, has led to the World Health Organization 1 classifying dementia as a global public health priority. Analysis of these modifiable risk factors has led to estimates that 40% of future dementia cases could be preventable. 3

From a policy perspective, there has been longstanding emphasis on earlier, more timely diagnosis to allow people with dementia and their families the option to undertake future shared decision-making.1,2,4, 1,2,4 Earlier detection may be approached in several ways. At a pre-symptomatic stage, systemic population screening involves identifying an illness, such as dementia, amongst a population of apparently asymptomatic individuals. 5 This form of population screening is currently not recommended for primary care,6–9 as it does not meet international criteria for adoption of screening programmes. 10 One requirement of this criteria is that the test is acceptable to the public. Another option for pre-symptomatic identification of an illness is targeted case finding, where individuals at known high risk of developing dementia for example, those with multiple risk factors, are assessed at an asymptomatic/undetected phase; however the acceptability, effectiveness, and cost effectiveness of this approach remains undetermined. 11

The WHO classification of dementia as a public health condition has resulted in greater attention being paid to targeted, and individualized dementia risk reduction approaches as a means of reducing future dementia burden. A largescale international consortium is testing individualized approaches to dementia risk reduction (International FINGERS). Research studies and surveys carried out by charitable organizations have captured positive attitudes regarding dementia screening from the public. In the USA, 75% of older adults expressed willingness to take a test to predict their likelihood of developing dementia in the future. 12 Similarly, evidence from a survey of 2,106 adults in the UK, with 51% indicating previous lived experience, caring responsibilities or connections with dementia, found 74% would be interested in knowing if they were at higher risk of developing dementia before symptoms occur, suggesting that dementia risk screening and population screening could be acceptable to many, should the evidence base justifying it be strong enough. 13 However, it must be noted that these research methods rarely provide the public with empirical evidence on the risk or benefits of screening, and results should be interpretated with caution.

In terms of potential screening tests for earlier detection of dementia, a systematic review, considering the evidence base up to 2012, suggested that simple, non-invasive assessment methods such as pen and paper cognitive assessments, blood-based biomarkers and telehealth assessments which could be used in primary care, would be most suitable. 5 The review also concluded that acceptability of screening is a complex and multi-factorial issue that is mainly deemed unacceptable to the public. At that time, seven factors contributed to the public’s perception of acceptability, including lifestyle and life view, dementia awareness, role of clinician, existing health state, benefit, communication and role of family. However, this review was unable to make any statements relevant to under-served populations, i.e., demographic groups with typically low inclusion rates in research, higher healthcare burdens or which require better service provision from research/healthcare. 14 Ethnic minority groups are significantly under-served in dementia research, as they are under-represented in clinical trials and dementia prevention programmes 15 which means that clinical and policy decisions may not reflect discrete cultural and social needs. 16 Additionally, these groups have unique barriers and experiences which may negatively impact help-seeking behaviors regarding cognitive concerns, and current cognitive assessments may not be culturally-sensitive or appropriate, leading to further inequities in their access to diagnostic services.17–19 Additionally, socio-economic status is generally under-reported in dementia research despite lower socio-economic groups having a higher dementia risk20,21, 20,21 and worse prognostic outcomes following diagnosis. 22 To ensure information relevant to policy decisions regarding implementation of dementia screening is representative, it is important to consider these key under-served groups’ unique perspectives on the acceptability of dementia screening, and the facilitators and barriers for undergoing such screening. For example, in relation to other healthcare screening services, people from ethnic minorities highlighted cultural factors, religion and acculturation as key influences on uptake,23–25 while those from lower socio-economic groups have lower uptakes of cancer screening services. 26 Given the rapid knowledge changes in the dementia risk-reduction and treatment landscape, and the greater emphasis on including under-served populations in research, the aim of this systematic review is to update the Martin et al. 5 review with a specific aim to evaluate the attitudes and preferences of people affected by dementia, carers and the general public from ethnic minorities and low socio-economic groups regarding screening for dementia; both perceptions on targeted case finding and general population screening for undetected dementia are included. This review will update researchers and policy-makers focused on developing dementia screening initiatives on the current status of acceptability of screening programs, key to international criteria for implementation.7,8,10,27, 7,8,10,27 Additionally, findings from this review will inform recommendations for future dementia screening initiatives, based on the perspectives and priorities of these key under-served groups.

METHODS

This systematic review was preregistered on PROSPERO (CRD42023384115) and reporting follows PRISMA (Preferred Reporting Items of Systematic Reviews and Meta-Analyses) guidelines (see the Supplementary Material).

RESULTS

Search yield

The search strategy was conducted in February 2023 and generated 23,137 articles, of which 6,402 were removed due to duplication. Following title and abstract screening, 65 full texts were assessed for eligibility, of which 8 were included as seen in Fig. 1.

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Fig. 1

PRISMA flow chart demonstrating search yields through different phases of the systematic review. LSES, Lower socio-economic status.

DISCUSSION

To our knowledge, this is the first systematic review to consider the attitudes and preferences of under-served groups, such as people from ethnic minorities and low socio-economic groups, regarding dementia screening. Most papers considered general population screening for undetected dementia, as opposed to targeted case-finding in those at high risk of dementia. Key results suggest that willingness to undergo screening is relatively high in diverse ethnic minority groups, but that there is a significant gap in the literature regarding low socio-economic groups and ethnic groups outside USA. Willingness to undergo screening is linked to perceived benefit of results, promotion of diversity within research, and negative outcomes relating to a positive result. Practical considerations for screening include awareness of cultural and economic barriers, trustworthiness of healthcare providers, post-screening outcomes and use of non-invasive tests.

Ethnic minority participants in the reviewed studies were highly willing to undergo dementia screening—both for screening of undetected dementia and for dementia risk. It is unclear what materials these individuals had to guide these decisions, and what evidence bases were presented, or what media these groups consumed. Positive perceptions of dementia screening were associated with belief that early detection would support management and treatment of dementia and decelerate progression via lifestyle changes. This is in contrast to a previous review, which included a majority white population that reported a low willingness to undergo screening (Martin et al. 5 ). The differences between the previous review and ours may relate to cultural factors and/or may be reflective of the changing landscape of dementia research and risk awareness since 2015. For example, regarding screening for dementia risk, the first Lancet Commission on dementia prevention, intervention and care was published in 2017 and suggested that approximately 35% of dementia cases were attributable to modifiable risk factors 40 ; the updated report in 2020 increased this to 40% preventable dementia cases. 3 Regarding screening for undetected dementia, WHO released their global action plan for dementia in 2017, calling for the development of national policies and plans for dementia across the globe, including the promotion of early diagnosis in an unspecified manner, improvement of the general public’s knowledge about dementia and requirement of case-finding services for undetected dementia within healthcare. 1 Given the prevalence of USA-based studies in this review, it is notable that the Alzheimer’s Association released guidance in 2013 for systematic cognitive screening during the Medicare Annual Wellness visit in those aged 65 or over, while the American Academy of Neurology recommended annual cognitive screening in this population in 2019.41,42, 41,42 These advances were met with significant media interest and public health campaigns which may have increased the perception of benefits from dementia screening, 40 despite a recent study demonstrating that dementia screening does not improve quality of life, healthcare utilization or advanced care planning. 43

Results indicated that lower socio-economic groups were more skeptical regarding dementia screening; this is based only on one study and is therefore not generalizable. It is notable however that there is a dearth of research considering the perceptions of those from lower socio-economic groups. Additionally, the ethnic minorities represented in this review are mainly drawn from USA studies and therefore findings on attitudes and preferences may not be transferable to those living in other regions. Additionally, while ethnic groups were often described in broad categories (e.g., Hispanic), there can be significant heterogeneity within these groups, as noted by Galvin et al. 39 , who encompassed South American, Puerto Rican, Dominican, Mexican, and Central American in their “Hispanic” category. It is likely that there are different languages, dialects, cultures, customs, religions and experiences both between and within these groups which may impact their perceptions of dementia screening; these nuances are likely not captured in the results of this review. Exploring the views of ethnic minority and low socio-economic groups across multiple high-income countries may have highlighted unique preferences regarding dementia screening, such as areas relating to cultural expectations and roles and religiousbeliefs.44,45, 44,45

Commonalities were found between the thematic results from the systematic review by Martin et al. 5 and this update, particularly regarding dementia awareness, the role of the clinician, communication and perceived benefits of dementia screening. Both reviews highlighted a low level of dementia awareness leading to misunderstandings regarding dementia screening; for example, members of the Hispanic population were concerned that screening would involve processes similar to electroconvulsive therapies. 33 Culturally-specific educational programs appeared to have a positive effect on enhancing dementia awareness and increasing interest in screening in Hispanic populations.33,35, 33,35 Martin et al. 5 suggested that clinicians needed to communicate their role clearly and explain how they would conduct the tests and interpret results. In this updated review, ethnic minority groups were more concerned regarding the trustworthiness of the healthcare provider conducting the screening, particularly regarding their relationship in the local communities.34,36, 34,36 Both reviews highlight similar perceptions regarding the benefits of dementia screening. However, this update suggests that members of the African American community may be more likely to become involved in biomarker studies to improve diversity within research, 37 it is notable that this group was well-educated (45.5% with a Bachelor’s degree). Specific cultural and economic barriers to screening were also highlighted in this review regarding language issues, lack of transport, lack of confidence in medical care and worries regarding impact on health insurance and job security.33,35,36, 33,35,36

In terms of the implications for public health policy and practice, the 2023 World Alzheimer Report, Reducing Dementia Risk; Never too early, never too late’ concluded that “in the absence of a cure or a treatment that is globally accessible, risk reduction remains the most feasible and proactive way to combat dementia” on an international scale. 2 It urged governments to include national risk reduction programs within their dementia plans/strategies and invest more research funding into this area, in addition to the search for new treatments; the latter are highly unlikely to be readily available to the majority of people with dementia worldwide who live in Low-Middle Income Countries (LMICs). Additionally, national guidelines (e.g., 5th Canadian Consensus Conference on the diagnosis and treatment of dementia) have suggested that screening for undetected dementia may be appropriate when patients are identified with elevated risk, as per recognized risk factors. 46 This review has shone a light on the attitudes and preferences of ethnic minorities on dementia screening; however, the findings are based on research from two High Income Countries, with a significant absence of empirical research from LMICs. This is a significant research gap as some LMICs such as South East Asia countries, and minority groups, e.g., those of South Asian ancestry, are predicted to experience the highest future increases in dementia numbers in the next few decades. 47

Ethnic minority groups have different risk factors, prognosis, health seeking behaviors, and experiences of care, marginalization and systemic racism compared to non-ethnic minorities. Regarding dementia, specific cultural attitudes and disease-related stigma have been described within ethnic groups and national risk reduction strategies would need to be inclusive of such societal attitudes and beliefs. 4 Thus under-representation of ethnic minorities’ perspectives in dementia research leads to the development of clinical and policy decisions that do not reflect their needs. This review demonstrates tangible findings regarding cultural and economic considerations for the practicalities of dementia screening. Based on these findings, we have developed recommendations as presented in Table 3.

Significant strengths of this systematic review include building upon the previous Martin et al. 5 review with consideration of the changing landscape regarding inclusion of under-served populations in research. 14 This has important implications as different sociodemographic groups may respond differently to the offer of dementia screening and risk-reduction, and interventions cannot be appropriately tailored without synthesizing the research within these groups. This review’s protocol was pre-registered, and PRIMSA guidelines were followed throughout the process. Additionally, any future studies in this area must ensure that the knowledge base of the individuals responding with regard to the actual state of evidence regarding ‘early’ diagnosis is known in order to interpret the findings. Opinions can change when full disclosure of the gaps in evidence are fully described. For example, participants in a citizen jury study did not believe GPs should practice case-finding for dementia after expert information regarding benefits, challenges and harms were presented to them. 48

However, due to limited resources, our title screening involved one reviewer screening all titles and a second reviewer screening a random selection of 40% of the titles. While this provides a quality control mechanism to minimize bias, and is more reliable than a single screening process, this may have affected our ability to identify all relevant articles. Single screening of titles and abstracts can be considered as an appropriate methodological shortcut,49,50, 49,50 in our case, we applied partial dual-screening to minimize error. We also note that of the 6,766 titles reviewed by both reviewers,>99% of decisions were in agreement (0.006% disagreement). The high concordance of double screening makes this unlikely. 49 To mitigate against further risk of bias, two reviewers independently screened all abstracts and full texts, and a hand-search of the reference lists of all included texts was conducted. Additionally, although we conducted the search strategy in six databases, all articles identified were in English; alternative databases may have been more inclusive to non-English research articles, which may have impacted this review’s key results. However, it is noted that language restrictions in systematic reviews in the medical sciences field is considered to have minimal impact on results and conclusions for most topics, and is considered a viable approach for systematic reviews with limited resources.51–53 The majority of studies included in this review were conducted in the USA, highlighting a significant gap in the literature regarding diversity of research in non-USA countries. Additionally, only one German study considering low SES was identified, strengthening the suggestion that this group is under-served by research. However, it must be noted that we only included studies which explicitly stated they were studying SES. The definition of SES is complex and unstandardized, generally involving multiple intersectional factors such as income, education, class, place of residence, and in some cultures, ethnicity or race. Although these may be considered as “surrogates” of SES, this is not consistent across the literature. Therefore, we excluded studies that only reported findings for a discrete factor which contributes to SES (e.g., education, income), and suggest that future research consider measures to explicitly characterize SES as a composite, mindful of appropriate cultural standards, such as through national government statistics. Future work should consider greater geographical scope and inclusion of SES measures to develop a more representative understanding of attitudes and preferences towards dementia screening, in order to meet this criterion in the international screening criteria. 27

AUTHOR CONTRIBUTIONS

Manjot Brar (Data curation; Formal analysis; Investigation; Methodology; Writing – original draft); Ríona Mc Ardle (Formal analysis; Methodology; Writing – original draft); Alexander Hagan (Methodology; Writing – review & editing); Amani Al-Oraibi (Writing – review & editing); Matilda Hanjari (Methodology; Writing – review & editing); Blossom Stephan (Funding acquisition; Writing – review & editing); Carol Brayne (Funding acquisition; Writing – review & editing); Louise Lafortune (Writing – review & editing); Manpreet Bains (Funding acquisition; Writing – review & editing); Nadeem Qureshi (Funding acquisition; Writing – review & editing); Louise Robinson (Conceptualization; Funding acquisition; Methodology; Writing – original draft).