Dementia in Australia: How Alarming are the Predictions and What Difference Can Interventions Make?
In order to test hypothetical scenarios regarding future prevalence of dementia and impacts of interventions, we built a computer model to conduct virtual experiments. The computer model consists of two closely linked modules: a computational logic module representing stocks-and-flows (e.g., populations and transitions), and a user interface module with numerical controls and graphs. Our model predicts that a five year delay in the onset of dementia will lead to a 37% decrease in prevalence by 2040. An intervention that could delay the onset of dementia by 2 years, introduced in 2010, would result in a 16% reduction in prevalence by 2040. Slowing disease progression has little effect on the total prevalence of dementia, and in fact increases the prevalence. This increase is small and in the range of 4-7% of total prevalence. Total eradication of Alzheimer's disease (currently 50% of all dementia cases) in 2020 decreases the prevalence of dementia in 2040 by 42%. However, even with the eradication of all new cases of dementia in 2020, a legacy of already existing cases will survive for 20 years. In such a scenario there will be still around 40 000 people with dementia in Australia by 2040 - about 6% of the currently projected population for that year.