The number of people living with dementia globally is increasing. Estimated dementia prevalence is projected to increase from 57·4 million cases globally in 2019 to 152·8 million cases in 2050 (GBD 2019 Dementia Forecasting Collaborators, 2022). Negative stereotypes of the condition predominate (Low and Purwaningrum, 2020), and dementia has been cited as one of the most feared conditions amongst members of the public (MetLife Foundation, 2011; Kessler et al., 2012). Dementia research funding is increasing, with spending doubling in many Western countries between 2011 and 2016 (Pickett and Brayne, 2019). The importance of research into dementia prevention, and risk reduction is emphasised in the WHO’s Global action plan on the public health response to dementia 2017–2025 (WHO, 2017).

Burgeoning evidence supports the potential for dementia prevention globally. The Lancet Dementia Commission identified 12 modifiable risk factors which account for 40% of dementias globally (Livingston et al., 2020). The population attributable fraction for modifiable dementia risk factors is higher in low-and middle-income countries where certain risk factors are more prevalent (Livingston et al., 2020). Less childhood education, smoking, hypertension, obesity, and diabetes are, for example, more prevalent in China, India, and certain Latin American countries as compared to high income countries (Mukadam et al., 2019). Whilst improvements in cardiovascular risk reduction in particular may account for falling dementia incidence in Western Society (Larson et al., 2013; Wolters et al., 2020), these trends have not been replicated in Low-and Middle-Income Countries (LMICs; Li et al., 2007; Wu et al., 2018).

It is recognised that cognition exists on a spectrum encompassing normal cognition, subjective cognitive decline, mild cognitive impairment (MCI), and dementia (Knopman et al., 2015). People with MCI have cognitive impairment beyond that expected for age and education but remain functionally unimpaired (Petersen et al., 1999, 2021). The entities of subjective cognitive decline and MCI have represented opportune stages at which to intervene from a risk reduction perspective. Specific risk reduction strategies for those with MCI, as well as normal cognition, are set out in the World Health Organisation Risk Reduction of Cognitive decline and dementia guidelines (World Health Organization, 2019). In clinical settings, such risk reduction is increasingly addressed in a personalised and protocolised fashion. Evolving brain health services are likely in time to fulfil a number of roles, including risk profiling, risk communication, and risk reduction (Altomare et al., 2021). Furthermore, large scale, multidomain interventions have demonstrated the potential to benefit cognition in those at risk of dementia (Kivipelto et al., 2018). Particular efforts are ongoing to harmonise lifestyle intervention studies based on the FINGER study globally (Kivipelto et al., 2020). Such ‘high risk’ prevention strategies may however have limited impact at population level (Rose, 2001). Whilst secondary prevention in those with, or indeed seeking, a diagnosis is important, shifting the focus to encompass primary prevention in the general population is vital if dividends are to be seen at a population level (Milne et al., 2021). Population based strategies are radical and may confer a large benefit (Rose, 2001). Increasing awareness of modifiable risk factors for dementia represents a core function of dementia awareness campaigns (WHO, 2017). Indeed, lack of knowledge has been cited as the main barrier to behavioural change in dementia risk reduction (Curran et al., 2021). Barriers to engaging in risk reduction behaviours are numerous and diverse. In addition to lack of knowledge, existing research suggests that barriers might include lack of motivation, lack of time, organisational issues, financial reasons, health problems, and other factors (Heger et al., 2019; Curran et al., 2021; Van Asbroeck et al., 2021). In this context, whether risk reduction strategies are implemented on an individual or population level, it is uncertain if increasing awareness of dementia risk factors alone will be sufficient to engender behavioural change. Addressing barriers to dementia risk reduction is thus essential.

As illustrated elsewhere in this issue, modifiable risk factors for dementia remain prevalent in Ireland (Dukelow et al., 2023). A detailed examination of barriers to risk reduction behaviours in an Irish context has heretofore been lacking. More broadly, many existing studies examining barriers to brain health behaviours consider barriers generically, failing to examine how they might vary across different modifiable risk factors for dementia. In this context, this study aimed to undertake a detailed assessment of barriers to individual risk reduction behaviours. As existing research suggests that barriers to brain health behaviours may vary across sociodemographic factors (Heger et al., 2019; Van Asbroeck et al., 2021), we sought to investigate the distribution of barriers across factors such as age, gender, educational status, and household income.

In this study, we investigated barriers to lifestyle change to improve brain health in an Irish sample of adults aged 50 and above. Detailed subtyping of barriers, as well as examination of differences according to age, gender, education and income were undertaken, highlighting the diverse nature of barriers to brain health behaviours. Awareness of, and exposure to, modifiable risk factors for dementia, in addition to their associations with gender, age, and education were examined elsewhere and demonstrate a lack of awareness amongst our study population that dementia could be prevented through lifestyle modifications (Dukelow et al., 2023). Increasing knowledge in this regard has been identified as a potential priority in Ireland’s National Dementia public awareness campaign (Hickey, 2019). Effective dementia risk reduction approaches are likely to encompass individual and population focused approaches. In clinical contexts, it is anticipated that evolving memory clinics and dedicated brain health services will fulfil a significant role in dementia risk assessment, communication and delivery of personalised prevention (Frisoni et al., 2023). Our study highlights the individualised nature of risk factor profiles, and barriers to brain health behaviours, thereby underlining the utility of devising personalised risk reduction plans. Beyond secondary prevention, shifting the focus to encompass primary prevention in the general population is vital if dividends are to be seen at a population level (Milne et al., 2021). As well as increasing awareness of modifiable risk factors, we posit the argument that, in order to optimise their impact, public health interventions, rooted in the sociocultural contexts of their intended recipients, should target relevant barriers to risk reduction behaviours. It is recognised that homogeneous public health messages might not be persuasive to heterogeneous audiences (Wakefield et al., 2010). The heterogeneity of barriers to brain health behaviours revealed in this study further highlights that messaging may be irrelevant if it fails to take into account the gender, age, educational status, and income of its target audience. These points are further developed below.

In this study, clusters defined by lower socio-economic status (SES; as indicated by lower education and household income, namely clusters A and E) were disproportionately impacted by multiple risk factors, and several barriers were unequally distributed across socioeconomic groups. SES is a latent construct, comprising measures of income, education and occupation, or some combination of these factors (Baker, 2014). In a global context, income inequality has increased in most high-income countries, and in some middle-income countries since 1990 (United Nations Department of Economic and Social Affairs, 2020). Lower SES is associated with a 2.1-year reduction in life expectancy (Stringhini et al., 2017), and in its own right has been recognised as a barrier to healthy behaviour at mid-life (Kelly et al., 2016). Those of lower SES have a higher risk of dementia, a difference which is explained in part by modifiable risk factors (Deckers et al., 2019). From a dementia perspective, it is known that individuals with higher household income may benefit from earlier diagnosis (Petersen et al., 2021). In our study, those of lower household income were more likely to report lack of motivation as a barrier to consuming a healthy diet. Liking being by oneself was more likely to represent a barrier to social activity in those with lower household income. Home and work commitments, on the other hand, were more likely to represent a barrier to physical activity in those with higher household income. It has been suggested that effective public health programmes must take the needs of those with lower SES into account when designing interventions for dementia prevention at individual and societal level (Deckers et al., 2019). We further postulate that large scale interventions targeted at those of lower SES should be tailored to account for the barriers to risk reduction behaviours which disproportionately impact this cohort. Public health interventions, if they do not account for sociocultural contexts, may paradoxically serve to worsen health inequalities (Stephens et al., 2012). Behaviour change interventions for low-income groups have, however, demonstrated positive effects on physical activity, smoking, and healthy eating (Bull et al., 2014), all of which represent modifiable risk factors for dementia. Specific behavioural change techniques and delivery/context components may significantly increase the effectiveness of interventions targeting healthy eating and physical activity in low-income groups (Bull et al., 2018). The investigation of interventions targeting the broader spectrum of modifiable risk factors for dementia in lower SES cohorts, and clarification of individual components conferring effectiveness, represent priorities in the field of brain health research.

Educational status is significantly associated with awareness of multiple modifiable risk factors for dementia (Dukelow et al., 2023). In the context of dementia, education has long been thought to impact cognitive reserve, reducing susceptibility to age-related changes and Alzheimer’s Disease (AD) pathology (Stern, 2012). Higher educational status appears to impact dementia risk indirectly through its relationship with higher wealth and better lifestyle (Deckers et al., 2019). Lower educational attainment in women, however, is independently associated with an increased risk of dementia-related death (Russ et al., 2013). In our study, individuals of lower educational status were more likely to report a physical disability as a barrier to engaging in physical activity. This cohort were also more likely to report lack of knowledge with regard to accessing services as a barrier to treatment of low mood and depression. Individuals educated to undergraduate level or higher were more likely to report a range of practical barriers. Education is thought to impact health via multiple potential pathways (Cohen and Syme, 2013). Whilst the relationship between education and health behaviours such as smoking, alcohol consumption, and exercise is explained in part by differences in health knowledge, most effects remain after differences in knowledge are controlled for (Kenkel, 1991). Amongst other factors, attending university education is associated with a range of preventative health behaviours (Folta et al., 2009). More broadly speaking, as opposed to relating to quantity, health benefits may relate to the delivery of quality education (Cohen and Syme, 2013). The relationship between educational status, exposure to modifiable risk factors, and broader health outcomes has profound policy implications. Educational inequality has long been a theme in Irish educational discourse (Jeffers and Lillis, 2021). A policy central to tackling educational disadvantage in an Irish context is ‘Delivering Equality of Opportunity in Schools’ (DEIS). Whilst DEIS has demonstrated consistent success in improving academic outcomes across all grade levels (Kavanagh et al., 2017), considerable disparities persist. The consistent prioritisation of educational equity in national policy may ultimately have unintended benefits on health outcomes, potentially impacting dementia risk.

Our study highlighted multiple gender differences across barriers to brain health behaviours. Gender based inequalities related to dementia are widespread (Andrew and Tierney, 2018; Bartlett et al., 2018). Globally, females are disproportionately impacted by dementia. Dementia incidence rates are higher amongst women, with a particular divergence in incidence after the age of 80 (Beam et al., 2018). Disability adjusted life years (DALYs) due to dementia are approximately 60% higher amongst women than men (WHO, 2022). In our study, certain barriers disproportionately impacted female participants. Females were more likely to report particular emotional factors as being barriers to consuming a healthy diet and reducing alcohol intake. The disproportionate impact of stress in these contexts is broadly in keeping with previous work highlighting a tendency for women to relate stress to family and health-related events more frequently than men (Matud, 2004). Females were less likely to report practical factors as barriers to getting a good night’s sleep. At a population health level, designing risk reduction strategies to target gender-specific differences in reported barriers may confer additional impact. Previously, gender has been neglected in many National Dementia Strategies (Bartlett et al., 2018). Despite dementia’s disproportionate impact on those of female gender, it has been suggested that women’s focused dementia research is underfunded. Only 12% of the $2.398 billion 2019 NIH Alzheimer’s disease budget went to women-focused research (Baird et al., 2021). Gender-sensitive public health practise is a necessity, and recent years have seen delineation of implementation strategies at European level (Oertelt-Prigione et al., 2017). Successful examples of gender-sensitive public health interventions can be identified (Gaston et al., 2007; Folta et al., 2009), and may provide a basis for addressing gender-specific differences in brain health behaviours and associated barriers. The StrongWomen—Healthy Hearts programme for example has demonstrated efficacy in reducing cardiovascular disease risk in sedentary midlife and older women who were overweight or obese (Folta et al., 2009), and may provide a template for gender specific dementia risk reduction interventions.

Lack of motivation was the most often cited barrier across multiple cardiovascular risk factors (healthy diet, physical activity, smoking and alcohol excess). Cardiovascular risk factors were prevalent amongst the study population (Table 2). Whilst mortality related to stroke (Soto et al., 2021), and coronary heart disease (Marasigan et al., 2020) in Ireland are falling, the prevalence of some cardiovascular risk factors is increasing (Marasigan et al., 2020) and globally the burden of cardiovascular disease attributable to modifiable risk factors continues to increase (Roth et al., 2020). Burgeoning evidence supports a link between individual cardiovascular risk factors and Alzheimer’s disease dementia (Takeda et al., 2020). Whilst improvements in cardiovascular risk factor control may account for falling dementia prevalence in high-income countries, we demonstrate that cardiovascular risk factors remain prevalent in Ireland. Engaging and motivating those disinclined to participate may be hard to achieve via a public health campaign. In this context, the high prevalence of lack of motivation as a barrier to cardiovascular risk factor control in our study is concerning. Many social psychological models applied in a health behaviour context assume a degree of intrinsic motivation (Hardcastle et al., 2015). Whilst campaigns with mass media components aimed at increasing physical activity have yielded short-term increases, such increases are mainly in highly motivated individuals (Wakefield et al., 2010).

We have stressed the importance of tailored health communication in dementia risk reduction interventions. Tailored health communication may demonstrate increased personal relevance, thereby increasing intent to engage in behavioural change (Bol et al., 2020). Tailored health messaging aside, the authors advocate for the design, implementation, and evaluation of preventive, personalised medicine interventions targeting modifiable risk factors for dementia, and their associated barriers. Ideally, such studies would incorporate measures of genetic, and pathological risk which confer a far higher relative risk than the lifestyle factors discussed herein (Frisoni et al., 2023). The optimal means of evaluating such complex interventions is unclear and may no longer comprise traditional gold standard study designs such as randomised, controlled trials (Garton et al., 2022). Garton et al. (2022) highlight that complex interventions require complex evaluations, underlining the potential role of a non-standard research methodology, namely transdisciplinary research (TDR), in this context. Whilst definitions of TDR vary, common characteristics include, amongst others, transcending disciplinary boundaries through a focus on theoretical unity of knowledge; the inclusion of societal actors as process participants; a focus on specific, complex, societally relevant issues; and working in a transformative manner (Lawrence et al., 2022). TDR can influence scientific productivity and capacity, increasing academic output (Grigorovich et al., 2019). As well as impacting prespecified ‘traditional’ patient outcomes, TDR may have broader social impacts which are difficult to capture through traditional techniques such as assessing policy outcomes (Grigorovich et al., 2019). TDR may represent a promising means to tackle the ‘wicked problem’ (Rittel and Webber, 1973) of increasing dementia incidence.

This study is not without its limitations. The study design introduces the potential for selection bias as participants were members of an existing market research panel. Our study population was highly educated, perhaps limiting the degree to which our results are generalisable in a global context. Our exploration of barriers is systematic, and comparatively exhaustive, based as it is on the Behaviour Change Wheel and under-pinning COM-B model (Michie et al., 2011). It is, however, limited by the use of explicit questions and absence of free text responses which might have revealed novel barriers unanticipated by the research team. We thus cannot be sure that certain barriers for each risk factor were not missed. Patient and public involvement in survey design would have further strengthened this study.

Our study’s principal strength comprises its robust and comprehensive design. Existing literature highlights a multitude of barriers to dementia risk reduction behaviours. Lack of knowledge has been highlighted as the main barrier to behavioural change (Curran et al., 2021). Two studies utilising an identical survey instrument in different populations (Heger et al., 2019; Van Asbroeck et al., 2021) highlight lack of knowledge, and lack of motivation as the two most prevalent barriers. Other factors cited included lack of time, difficulty organising, financial reasons, health problems, and ‘other reasons’. Our work is differentiated by the survey construction, and risk factor-specific nature of the barriers contained therein. The results are likely to be useful in guiding public health messaging and intervention design. A range of barriers were explored across multiple risk reduction behaviours. The heterogeneity of barriers to brain health behaviours revealed in this study highlights the necessity to tailor public health interventions to their target population, taking into account the gender, age, educational status, and income of recipients. Our study serves to add weight to one of the stated goals of the WHO Global action plan on the public health response to dementia 2017–2025, namely the need to organise national and local public health and awareness campaigns that are community and culture specific.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

Ethical review and approval was not required for the study on human participants in accordance with the local legislation and institutional requirements. Written informed consent for participation was not required for this study in accordance with the national legislation and the institutional requirements.

TD and SPK were responsible for the concept and study design and were responsible for final review and editorial decisions. KM was responsible for design of the questionnaire on which the survey was based. TD, SPK, and EGL were responsible for amending and expanding the questionnaire. PV assisted with statistical analysis. Study writeup was undertaken by TD and SPK with input from LJ, EGL, PV, and IK. All authors contributed to the article and approved the submitted version.

This study received funding from Five Lives SAS/SharpTx Ltd., who sponsored performance of the survey.

This study received funding from Five Lives SAS/SharpTx Ltd., who sponsored performance of the survey. EGL and KM were previously employed by Five Lives SAS/SharpTx Ltd. LJ and PV are currently employed by Five Lives. IK is a paid medical advisor of Five Lives SAS/SharpTx Ltd.

The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.