Feasibility, acceptability, and cognitive benefits of a theory-informed intervention to increase Mediterranean diet adherence and physical activity in older adults at risk of dementia: the MedEx-UK randomised controlled trial

Background Despite an urgent need for multi-domain lifestyle interventions to reduce dementia risk there is a lack of interventions which are informed by theory- and evidence- based behaviour change strategies and no interventions in this domain have investigated the feasibility or effectiveness of behaviour change maintenance. Objectives We tested the feasibility, acceptability, and cognitive effects of MedEx-UK, a personalised theory-based 24-week intervention to improve Mediterranean-diet (MD) adherence alone, or in combination with physical activity (PA), in older-adults at risk of dementia, defined using a cardiovascular risk-score of >10%. Design 104 participants (74% female, 57–76 years) were randomised to three parallel intervention arms: 1) control, 2) MD, or 3) MD+PA for 24-weeks and invited to an additional 24-week follow-up period with no active intervention. Behaviour change was supported using personalised targets, a web-based intervention, group sessions and food provision. Results The intervention was feasible and acceptable with the intended number of ‘at risk’ participants completing the study. Participant engagement with group sessions and food provision components was high. There was improved MD adherence in the two MD groups compared with control at 24-weeks (3.7 points on a 14-point scale (95% CI 2.9, 4.5, p <0.01) and 48-weeks (2.7 points (95% CI 1.6, 3.7) p<0.01). Intervention did not change objectively measured PA. Improvements in general cognition (0.22 (95% CI 0.05, 0.35, p =0.01), memory (0.31 (95% CI 0.10, 0.51, p <0.01), and select cardiovascular outcomes captured as underpinning physiological mechanisms were observed in the MD groups at 24-weeks. Conclusion The intervention was successful in initiating and maintaining dietary behaviour change for up to 12-months, which was likely due to the intense early support provided which resulted in cognitive benefits. These results will inform larger-scale complex behaviour change interventions with health and well-being endpoints. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Trial NCT03673722 ### Funding Statement The main trial funding was from Alzheimers Research UK Prevention and Risk Reduction Fund (ARUK-PRRF2017-006) with additional support provided by the UK Nutrition Research Partnership (UK NRP), an initiative supported by the Medical Research Council (MRC), Biotechnology and Biological Sciences Research Council (BBSRC) and the National Institute for Health Research (NIHR) (MR/T001852/1) as part of the NuBrain Consortium work programme. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethical approval for the study was given by the National Research Ethics Committee Northern Ireland (18/NI/0191) I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The data that support the findings of this study are available from the corresponding author, upon reasonable request.