Discussion
memory and non-memory domains of cognition, dementia, nutritional and cognitive status, undernutrition
DISEASE, UNDERNUTRITION
To our knowledge, PROMED-EX is the first study aimed to evaluate the combined effects of a protein-enriched MedDiet and exercise on nutritional status and cognition in older adults at risk of undernutrition with SCD. Lifestyle interventions to address modifiable risk factors for dementia are likely to have a more significant public health impact when implemented at an early stage of disease and in high-risk populations. PROMED-EX will generate new knowledge about how a targeted lifestyle intervention delivered in a ‘real-world’ setting can impact nutritional and cognitive status among older individuals at risk of undernutrition and cognitive decline. A further novel aspect is the planned evaluation that will provide insight into lifestyle behaviour changes that are feasible and acceptable for the intended population.A key strength is the inclusion of a validated neurocognitive test battery in the current study allowing a comprehensive assessment of performance in both memory and non-memory domains of cognition as used in other multidomain interventions in adults at increased dementia risk.A further strength is the integration of state-of-the-art metabolomics, metabolic, inflammatory and nutritional biomarkers in the study will help to elucidate biological mechanisms underlying how diet can influence nutrition status and cognition, and how exercise may act to modify these processes. Furthermore, the interventions will be delivered using a personalised approach with incorporation of evidence-based techniques to support and encourage behaviour change. Study participants will also benefit from written educational resources that have been co-designed with PPI members to support the desired diet and exercise behaviour changes. The ongoing collaboration with PPI members in the trial will undoubtedly optimise the dissemination of study findings.There are some limitations to the study design that should be considered. The optimum period for lifestyle-induced change in nutritional status is not clear, and the duration of the current study intervention is shorter than in other multidomain trialsThe pragmatic study design means that we may have limited power to detect between intervention group effects on MNA. Furthermore, due to the novelty of the intervention and population, it was not possible to estimate sample size calculation for cognition; however, the findings generated from PROMED-EX on cognitive performance will be used to inform future studies.The level of research support for lifestyle behaviour change differs between the intervention and control groups where only the active intervention groups will receive weekly contact for the first 3 months to help meet intervention targets. As a result, intervention completers could be more motivated than control participants which may confound results. Lastly, consistent with other lifestyle interventions, participants will not be blinded to treatment allocation; however, data will be analysed by a blinded member of the study team to minimise detection bias.