An online, public health framework supporting behaviour change to reduce dementia risk: interim results from the Island Study Linking Ageing and Neurodegenerative Disease

Background: Behavioural and lifestyle factors contribute almost half of the risk of developing dementia. Addressing these factors might help prevent onset or slow disease progression. Given the rising prevalence and significant costs of dementia, a public health approach targeting these modifiable risk factors is warranted. Methods: The Island Study Linking Ageing and Neurodegenerative Disease (ISLAND) is a large, online, prospective public health research project. Over 13500 residents of Tasmania, Australia, aged 50+ years joined the project between 2019 and 2022, of whom 7270 consented to participate in research. Informed by health behaviour change models, participants’ knowledge, motivations, and behaviours related to modifiable dementia risk are measured at baseline and in annual surveys. Regression and mediation models were used to assess the effects of changes over time, and by exposure to two interventions: a personalised dementia risk profile (DRP) report provided after each survey wave, and the Preventing Dementia Massive Open Online Course (PDMOOC). Results: Data from 3038 participants (mean age 63.7 years, 71.6% female) were used in the reported analyses. The mean number of modifiable dementia risk factors reduced from 1.99 to 1.49 (out of 9) between joining the project and follow-up in 2022. This change was associated with time since baseline and the number of exposures to the DRP (b=-.06, p=.04) and was stronger for PDMOOC participants (b=-.14, p=.02). Markers of dementia risk literacy improved by DRP exposures (from b=.11 to b=.44, p<.001) and by PDMOOC engagement (from b=.16 to b=.38, p<.001). Six motivational factors changed by DRP exposure (from b=-.04 to b=.04, p’s<.021), with stronger effect sizes observed for PDMOOC participants in four factors (from b=-.19 to b=.15, p’s<.033). In PDMOOC participants, 13% of the observed behaviour change was mediated by changes in knowledge. Motivating factors – perceived susceptibility and self-efficacy – differentially affect the influence of higher knowledge on behaviour change. Conclusions: The ISLAND project offers a feasible public health framework for improving modifiable risk factors for dementia. The personalised DRP report and engagement with the PDMOOC work synergistically to increase dementia risk literacy and stimulate the intention and self-efficacy for changing risk behaviours.