Public Health.

Background: The Maintain Your Brain (MYB) randomised controlled trial (RCT) aimed to prevent cognitive decline and dementia through a multidomain risk-reduction intervention delivered digitally. The intervention targeted four modifiable risk areas (physical inactivity, poor diet, cognitive inactivity, and depression and/or anxiety). MYB ran for three years and targeted older Australians aged 55-77 years. We previously reported significant benefits on cognition in the intervention group compared to the control group. Here we report the outcome on a validated dementia risk assessment tool.

Method: The self-reported short form of the Australian National University Alzheimer's Disease Risk Index (ANU-ADRI-SF; 1) was used to assess dementia risk in MYB. To examine risk and protective factors, non-modifiable factors (age and sex) were removed. Unrealistic values were also removed as part of the data cleaning process. A generalised linear mixed model with appropriate response distributions and link function was run to examine the group (intervention vs control) by time (baseline, 12-, 24-, and 36-months) interaction. An additional analysis adjusted for baseline age, gender, and years of education was run.

Result: Of 14,064 participants who consented, 6,104 participants were eligible and completed baseline assessments. They were randomised 1:1 to the intervention (n = 3,051) or control (n = 3,053) group. Upon removing outliers (n = 58), 6,046 participants were included in the mixed model analysis. Analysis revealed significant intervention effects on dementia risk change over three years (0.56, 95%CI -0.88- -0.30, p<0.001). Results were replicated in the adjusted model (p<0.001).

Conclusion: An online intervention program confirmed results from a 24-month follow-up of in-person multicomponent interventions (2,3) in lowering dementia risk. Overall, MYB has the potential to provide a realistic path towards scalable community-based prevention of dementia, resulting in an improvement in public health and potential economic implications. References: 1. Kim S et al, Alzheimers Dement: Translational Res & Clin Interventions 2016;2:93-98 2. Barbera et al., Alzheimers Dement J Alzheimers Assoc. 2020; 16:S10 3. Deckers K et al. Alzheimers Dement. 2021;17:1205-1212.