Body, Brain, Life for Cognitive Decline (BBL-CD): protocol for a multidomain dementia risk reduction randomized controlled trial for subjective cognitive decline and mild cognitive impairment

Mitchell McMaster,1 Sarang Kim,1 Linda Clare,2 Susan J Torres,3 Catherine D’Este,4 Kaarin J Anstey1,5,6 1Centre for Research on Ageing, Health and Wellbeing, Research School of Population Health, The Australian National University, Canberra, ACT, Australia; 2Centre for Research in Ageing and Cognitive Health, University of Exeter, Exeter, UK; 3Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, Australia; 4National Centre for Epidemiology and Population Health, Research School of Population Health, The Australian National University, Canberra, ACT, Australia; 5Neuroscience Research Australia, Sydney, NSW, Australia; 6School of Psychology, University of New South Wales, Sydney, NSW, Australia Background: With no cure for dementia and the number of people living with the condition predicted to rapidly rise, there is an urgent need for dementia risk reduction and prevention interventions. Modifiable lifestyle risk factors have been identified as playing a major role in the development of dementia; hence, interventions addressing these risk factors represent a significant opportunity to reduce the number of people developing dementia. Relatively few interventions have been trialed in older participants with cognitive decline (secondary prevention).Objectives: This study evaluates the efficacy and feasibility of a multidomain lifestyle risk reduction intervention for people with subjective cognitive decline (SCD) and mild cognitive impairment (MCI).Methods: This study is an 8-week, two-arm, single-blind, randomized controlled trial (RCT) of a lifestyle modification program to reduce dementia risk. The active control group receives the following four online educational modules: dementia literacy and lifestyle risk, Mediterranean diet (MeDi), cognitive engagement and physical activity. The intervention group also completes the same educational modules but receives additional practical components including sessions with a dietitian, online brain training and sessions with an exercise physiologist to assist with lifestyle modification.Results: Primary outcome measures are cognition (The Alzheimer’s Disease Assessment Scale-Cognitive-Plus [ADAS-Cog-Plus]) and a composite lifestyle risk factor score for Alzheimer’s disease (Australian National University – Alzheimer’s Disease Risk Index [ANU-ADRI]). Secondary outcome measures are motivation to change lifestyle (Motivation to Change Lifestyle and Health Behaviour for Dementia Risk Reduction [MCLHB-DRR]) and health-related quality of life (36-item Short Form Health Survey [SF-36]). Feasibility will be determined through adherence to diet (Mediterranean Diet Adherence Screener [MEDAS] and Australian Recommended Food Score [ARFS]), cognitive engagement (BrainHQ-derived statistics) and physical activity interventions (physical activity calendars). Outcomes are measured at baseline, immediately post-intervention and at 3- and 6-month follow-up by researchers blind to group allocation.Discussion: If successful and feasible, secondary prevention lifestyle interventions could provide a targeted, cost-effective way to reduce the number of people with cognitive decline going on to develop Alzheimer’s disease (AD) and other dementias. Keywords: dementia prevention, dementia risk reduction, secondary prevention, Alzheimer’s disease, subjective cognitive decline, mild cognitive impairment, multidomain lifestyle interventio