Dementia in Australia

Dementia can manifest as a symptom of other diseases, infection or injury.

The number of people in Australia living with these less common types of dementia is not known. There are some data on hospitalisations and deaths where rarer dementia types are recorded, however, these are limited and should be interpreted with caution as coding of dementia type can be inconsistent and can vary by region of residence (AIHW 2023b; Waller et al. 2021).

Parkinson’s disease dementia

Parkinson’s disease, Parkinson’s disease dementia, and dementia with Lewy bodies are three overlapping disorders that are forms of Lewy Body disease. They share similarities in the ways by which they damage the brain at the cellular level and in the symptoms a person may experience. For more information, see Lewy body disease.

Globally, the prevalence of Parkinson’s disease has been increasing (GBD 2016 Neurology Collaborators 2019) and an estimated 20%–40% of people with Parkinson’s disease also have dementia (Åström et al. 2022).

In Australia:

• prevalence estimates for Parkinson’s disease vary widely (Deloitte Access Economics 2015; Parkinson’s NSW 2024)
• in 2021, among people who had dementia recorded as an associated cause of death, Parkinson’s disease was the leading underlying cause of death (UCOD) for men aged 65–74, and the fourth leading UCOD overall (almost 830 people)
• between 2003 and 2023, the rate of fatal burden of disease (years of life lost) due to Parkinson’s disease increased by 57% for men and 24% for women (AIHW 2023a)
• Dementia in Parkinson’s disease was recorded as the dementia type in 1.7% of hospitalisations due to dementia (2.4% for men, 1.0% for women) in 2021–22
• Lewy Body dementia was recorded as the dementia type in 2.6% of hospitalisations due to dementia (3.3% for men, 1.8% for women) in 2021–22.

See Hospitalisations by type of dementia and Leading underlying causes of death.

Dementia due to the effect of alcohol and other substances

The use of alcohol and other harmful substances can have long-term impacts on brain health (Dementia Australia 2018). In 2021–22, Dementia due to the effect of substances was recorded as the dementia type in 1.1% of hospitalisations due to dementia (1.6% for men, 0.6% for women).

For more information, see Alcohol related dementia.

Huntington’s disease

Huntington’s disease is an inherited genetic condition that progressively affects the nervous system and causes dementia. It can occur at any age, but people usually start experiencing symptoms in young-middle aged adulthood. For more information, see Huntington’s disease.

According to a recent Australian report (Layton and Brusco 2020):

• the prevalence rate of Huntington’s disease was estimated at 8.4 per 100,000 people (about 2,160 people)
• about 830 people diagnosed with Huntington’s disease were receiving a National Disability Insurance Scheme (NDIS) package on 31 December 2019
• about 40 people with Huntington’s disease moved into permanent residential aged care per year between 2013–14 and 2017–18.

Due to low numbers, Dementia in Huntington’s disease is currently grouped under Other dementias in the Dementia in Australia data. Work is underway to provide more detailed data where possible.

HIV associated dementia

The human immunodeficiency virus (HIV) can infect brain cells, causing cognitive impairment. The most severe form of impairment is called HIV associated dementia. Since the introduction of combination antiretroviral therapy, HIV associated dementia is rare in high income countries, affecting 2–8% of people living with HIV (Saylor et al. 2016).  

For more information, see HIV associated dementia.

Due to low numbers, Dementia in HIV is currently grouped under Other dementias in the Dementia in Australia data. Work is underway to provide more detailed data where possible.

Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease (CJD) is a very rare degenerative brain disease that causes dementia. CJD usually develops spontaneously (called sporadic CJD), but other forms of the disease can be genetically inherited or acquired from external sources.

For more information, see the CJD Support Group Network.

CJD is the most common of the human prion diseases. In Australia, an average of 35 new cases of human prion disease were reported each year between 1993 and 2022 (Stehmann et al. 2023). There has been an increase in the number of cases of sporadic CJD reported over time, likely due to a combination of an ageing population and improved detection.

Due to low numbers, Dementia in CJD is currently grouped under Other dementias in the Dementia in Australia data. Work is underway to provide more detailed data where possible.

Chronic Traumatic Encephalopathy dementia

Chronic Traumatic Encephalopathy (CTE) is a type of dementia caused by repeated head injuries. These injuries may occur while playing sport, or through other forms of head impact such as violent assault, family and domestic violence, frequent falls, or during military service.

For more information, see Chronic Traumatic Encephalopathy dementia.

There is a lack of data on the prevalence and impact of CTE and its causes. Data development initiatives include the National Sports Injury Data Strategy, the Australian Sports Brain Bank and the Australian Veterans Brain Bank.

Childhood dementia

Childhood dementia results from progressive brain damage and is caused by over 100 rare genetic disorders (Elvidge et al. 2023). Collectively, childhood dementia has an estimated incidence rate of 84.3 per 100,000 births (1 in 2,900 births) and an expected prevalence rate of 5.3 per 100,000 persons in high and upper-middle income countries (Elvidge et al. 2023). 

For more information, see the Childhood Dementia Initiative.

Data on childhood dementia are not currently reported in Dementia in Australia. Work is underway to address this data gap.