Dementia is a serious and growing health problem in Australia and numerous other countries with an ageing population. The Australian Burden of Disease Study (ABDS) 2011 estimated that dementia was responsible for 3.4% of the total health burden due to disease and injury in Australia in 2011. Among people aged 65 and over, dementia was the second leading cause of total burden (7.8%) and the leading cause of non-fatal burden (10%). There is currently limited effective treatment available and no cure for dementia.

This report looks at a range of modifiable vascular risk factors for dementia, and estimates their individual and combined contribution to the burden of dementia in Australia. Vascular risk factors in this study include: smoking, physical inactivity, midlife high blood pressure and midlife obesity, as well as vascular diseases that act as risk factors for dementia—diabetes, stroke, atrial fibrillation and chronic kidney disease. It uses burden of disease estimates from the ABDS 2011 and evidence in the literature that shows a link between these vascular risk factors and development of dementia in later life.

This report also includes scenario modelling to assess the potential impact on future dementia burden if risk factor exposure levels were reduced to meet the World Health Organization (WHO) targets in 2020 compared with current trends in risk factor prevalence continuing.

Prospects for prevention

The analysis in this report indicates:

  • about 30% of the total dementia burden in Australia was due to the joint effect of the vascular risk factors examined
  • the proportion of dementia burden attributable to the combined risk factors increased with age
  • the individual risk factors contributing most to the dementia burden were
    • behavioural risks—physical inactivity (contributing 8.0% of dementia burden) and tobacco use (4.8%)
    • metabolic risks—high blood pressure in mid-life (6.0%) and obesity in mid-life (5.6%)
    • diseases-as-risks: chronic kidney disease (8.4%), stroke (6.7%), diabetes (5.3%) and atrial fibrillation (5.2%)
  • males experienced a greater proportion than females of the dementia burden attributable to each risk factor, except for physical inactivity (males 7.4%; females 8.3%) and chronic kidney disease (males 7.4%; females 9.0%).

Impact of risk factor reduction on future dementia burden

Reducing risk factor prevalence to meet targets set by the WHO could result in a 14% reduction in dementia burden attributable to the vascular risk factors in 2020.

The largest health gains are expected from reducing the prevalence of diabetes (48% reduction in dementia burden due to diabetes), obesity in mid-life (26%) and physical inactivity (15%).