The Island Study Linking Ageing and Neurodegenerative Disease (ISLAND): A longitudinal public health research program targeting dementia risk reduction

Background: A substantial proportion of risk for age-related dementia may be attributable to modifiable factors. The ISLAND Project responds to international calls (Lancet Commission, World Health Organisation) to investigate the effectiveness of public health strategies for reducing dementia risk. This large longitudinal and interventional cohort study will evaluate a sustained public health campaign to mitigate behaviours associated with dementia risk. The Tasmanian population comprises approximately 500,000 urban, rural and remote residents and has a prevalence of factors associated with dementia risk that is higher than Australian norms. This contained island population offers a unique opportunity for recruitment, cohort maintenance and tracking changes in participants’ dementia risk profile over time.

Method: The ISLAND Project aims to recruit 10% of Tasmanians aged 50 and over (target n=20,000). Participants will be offered a series of educational and community-based interventions to build self-efficacy in dementia risk management. Engagement with these interventions will be evaluated. Self-report, online surveys administered annually will track changes in participants’ physical and mental health, social functioning, dementia risk literacy and risk-related behaviours. Cognitive screening and biomarkers (e.g. blood) will be collected biennially. The Dementia Risk Profile (DRP) will support and track behaviour change. The DRP provides a traffic-light indicator of personal risk and recommended actions, based on WHO risk reduction guidelines. The DRP can be updated every six months and printed to support health consultations.

Result: The ISLAND Project launched in June 2019. Preliminary data collected between October and December 2019 indicate the ambitious recruitment target is feasible, with 10,729 registering interest in the study, of whom 4,937 have provided research consent (73% female, median age 62 years). Participants’ postcodes signify reasonably representative geographical distribution (urban 77%, rural 22%; Figure 1) and current baseline data include: background and health (n=4270), knowledge (n=3781) and attitudes about dementia risk (n=3588), depression (n=3541) and the DRP (n=3269).

Conclusion: The ISLAND Project aims to translate, into a public health setting, research evidence that reducing dementia risk can be achieved through modifying behaviours. Findings from this population-based approach to dementia risk reduction will be used to inform future public health policy and practice.