3: Dementia prevalence and incidence
There are 8 activities proposed to improve available data on dementia prevalence and incidence in the population. Some activities are directly focused on improving dementia prevalence and incidence data overall, while others are focused on improving or developing new data. Further, some activities are dependent on the completion of other activities in this plan.
Activities to improve dementia prevalence and incidence data include:
- 3a: Incorporate dementia data in enduring linked data assets to meet the needs of dementia monitoring
- 3b: Increase coverage of existing data for national dementia incidence monitoring
- 3c: Investigate approaches to estimate the national prevalence of dementia
- 3d: Assess new self-reported dementia data collected in the 2021 Census
- 3e: Estimate dementia prevalence in priority population groups
- 3f: Develop a Regional Insights portal of dementia data for local areas
- 3g: Assess impact of dementia coding changes in ICD-11 when incorporated in the Australian health system
- 3h: Improve national dementia prevalence estimates using linked data.
These activities may involve single projects, or multiple projects to enable monitoring of trends over time, incorporate improvements in data or to focus on a specific population group. Each activity provides information on the intended outcome, level of investment required, timeframe for completion of the activity and who is responsible for undertaking the activity.
Activities aimed at improving dementia diagnosis data in primary and secondary health care data would also improve dementia prevalence and incidence data. See Dementia diagnosis and management for additional activities
Activity 3a: Incorporate dementia data in enduring linked data assets to meet the needs of dementia monitoring
There have been substantial developments and progress made with enduring linked data assets in recent years. The AIHW is aiming to expand an enduring linked data asset, which would allow approved projects to access data sets within the linked data asset using streamlined governance arrangements and pre-existing linkages of widely used health and aged care administrative data.
This activity involves the inclusion of dementia-focused data sources (such as data from Dementia Support Australia and the ADNeT Registry) in existing enduring linked data assets for dementia research and monitoring. Once the linked data asset is established and data governance and approvals are in place, dementia analysis would draw on data sets from the linked data asset including mortality data, hospital data, Pharmaceutical Benefits Scheme (PBS), Medicare Benefits Schedule (MBS), aged care, and any other relevant data sets which would improve dementia monitoring. Other relevant data sets could include data from the Department of Social Services Data On Multiple INdividual Occurrences (DOMINO), National Disability Insurance Scheme (NDIS), and Department of Veterans’ Affairs (DVA). This would allow for monitoring of people with dementia accessing welfare and disability support services, and services offered by DVA.
The enduring linked data asset could improve available data on a range of priority topics identified in the National Centre for Monitoring Dementia (NCMD) work plan, including culturally and linguistically diverse (CALD) status (for example, country of birth at a minimum), First Nations people, dementia among veterans, younger onset dementia, childhood dementia and rarer causes of dementia.
This activity relies heavily on improvements in existing national data infrastructure and governance arrangements, and ideally would be made available to all researchers.
| Outcome | Better diagnosis, prevalence, cost, services, transitions to aged care and outcomes data for the Australian national population and by priority groups. Improved data aligns with NDAP action 8 and has potential benefits for several NDAP areas including actions 4, 5, 6 and 7. |
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| Level of investment | Medium–high: The level of investment is dependent on the number of data sets to be linked and the resourcing involved to maintain an enduring linked data set. Work to include a single data source into an enduring linked data set would require medium investment. However, in total this is a high investment activity. |
| Timeframe | Short for incorporation of single data set; Long to meet needs of dementia monitoring. Work to include a single data source could commence now and be completed in the short term, however, incorporating multiple data sources to suit dementia monitoring needs and maintaining an enduring linked data set are long-term activities. |
| Responsible stakeholder | AIHW NCMD |
| Progress | The AIHW has completed two separate pilot data linkages to the National Health Data Hub. The first linkage is with Dementia Support Australia (DSA) data and the second linkage is with ADNeT Registry data. Pending outcomes from analytical work conducted with these pilot linkages, the potential for enduring linkages will be explored. In a separate piece of work evaluating dementia identification in data sources (activities 3d and 3h), the AIHW has completed a one-off linkage of dementia information from hospital and aged care data into the ABS Person Level Integrated Data Asset (PLIDA). Additionally, National Disability Insurance Scheme (NDIS) data is now available in the AIHW National Health Data Hub and the ABS PLIDA. These data will enable AIHW to monitor people with dementia accessing disability support services, in particular people living with younger onset dementia and childhood dementia, in future work, such as activity 10a. |
Activity 3b: Increase coverage of existing data for national dementia incidence monitoring
This activity involves investigating potential existing sources of dementia incidence data (such as from the ADNeT Registry, the ADAPTOR study and other epidemiological studies) and determining what work could be undertaken to estimate what coverage is required and how this could be achieved. This activity is focused on reviewing available data from existing studies and registries and recommends activities to expand sources to achieve nationally representative dementia incidence data. Following outcomes from this investigation, this plan would be updated to incorporate new activities.
Activities aimed at improving dementia diagnosis data in primary and secondary health care data would also improve dementia incidence data (see Dementia diagnosis and management for additional activities).
| Outcome | Recommendations on activities to expand existing data sources to achieve nationally representative dementia incidence data. |
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| Level of investment | Low: The level of investment to undertake initial work to investigate potential sources and what coverage is required to improve national estimates of dementia incidence is low. Work to expand existing data to improve capture of dementia incidence and monitor this on an ongoing basis would be a high investment activity. |
| Timeframe | Short |
| Responsible stakeholder | AIHW NCMD; academic researchers |
| Progress | In November 2024, the AIHW hosted a workshop that focused on improving Australia’s dementia prevalence and incidence data (see Activity 3c). In addition, The AIHW has developed new data linkages including linking ADNeT Registry data with the National Health Data Hub, and linking dementia information from hospital and aged care data to the ABS Person Level Integrated Data Asset (PLIDA) (see activities 3d and 3h). Future work could evaluate how these data could be used for incidence monitoring. |
Activity 3c: Investigate approaches to estimate the national prevalence of dementia
This activity involves a systematic investigation of different options (and combinations) to better estimate the prevalence of dementia. Completion of this activity would result in recommendations for estimating national prevalence of dementia, including among key priority groups.
This would involve assessing current international and national data and methods used to estimate dementia prevalence. This would evaluate if international approaches are appropriate for the current Australian context and if small-scale Australian studies could be appropriately scaled up to meet national monitoring needs.
Following this investigation, this plan would be updated to incorporate new activities to implement the recommendations. Suitable data sources identified in this activity could also be used to compare and validate existing and emerging prevalence estimates from national enduring linked data sets.
| Outcome | Recommendations of activities to improve national estimates of dementia in Australia, goal 1 of this plan. |
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| Level of investment | Low: The level of investment to identify activities for improving national dementia prevalence data is low. Depending on the type of activity, subsequent work to implement the activity would require medium-high investment. |
| Timeframe | Short |
| Responsible stakeholder | AIHW NCMD in collaboration with input from academic researchers and experts in population-based studies. |
| Progress | Complete: The AIHW consulted experts in late 2023 on activities needed to improve Australia’s dementia prevalence data. From these consultations, high-level recommendations for activities and investment required to improve dementia prevalence data in Australia were provided to the Department of Health, Disability and Ageing. In November 2024, the AIHW hosted a workshop that focused on improving Australia’s dementia prevalence and incidence data. The objectives of this workshop were to generate practical and immediate next steps, including ongoing work using existing resources in addition to future data improvement activities. Workshop attendees included representatives from relevant government agencies involved in monitoring Australia’s health with epidemiological and clinical researchers with expertise in dementia. Ideas discussed at the workshop are being further considered by the NCMD. This includes approaches for activity 3e, as well as activity 3h, which has been added to this plan in 2025. |
Activity 3d: Assess new self-reported dementia data collected in the 2021 Census
The 2021 Census included a question on long-term health conditions including dementia for the first time. A current project under the NCMD aims to compare self-reported dementia records in the 2021 Census with dementia records in other data sets available in the Person Level Integrated Data Asset (PLIDA).
While there is potential that the 2021 Census data could capture people with mild to moderate dementia who have not yet had contact with hospital or aged care services (and thus be a valuable source for capturing additional cases), there is also potential that the public are not willing to share health information in the Census, leading to under-reporting. Analysis of dementia data from the Census will inform prevalence estimate methods and guide advocacy for the inclusion of dementia as a long-term health condition in subsequent Censuses.
Census data contains demographic information which may enable reporting by priority groups including First Nations people and people living with younger onset dementia.
| Outcome | Inform the use of Census data for monitoring dementia and estimating dementia prevalence in Australia; provide evidence to support the inclusion of a question on dementia in future Censuses. |
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| Level of investment | Low |
| Timeframe | Short |
| Responsible stakeholder | NCMD |
| Progress | Complete: The NCMD has assessed the self-reported dementia data collected from the 2021 Census. This work compared people living with dementia captured in the Census to other health, aged care and support services data. Results are expected for public release in 2026–27. The 2026 Census will retain the long-term health condition question and the AIHW are continuing conversations with the ABS on the value of long-term health condition information. |
Activity 3e: Estimate dementia prevalence in priority population groups
This activity involves establishing methods and implementing studies to estimate dementia prevalence in priority populations. This may involve undertaking new dementia prevalence studies, expanding existing studies to improve the capture of dementia or using linked data to estimate dementia in priority population groups (if considered appropriate). The data collection methods would need to be designed to be culturally appropriate, recognising that different cultural attitudes around dementia will require different approaches. Activities should be designed to maximise participation and data collection. For this reason, the activity would involve distinct projects for specific population groups.
| Outcome | Improved methods and data to estimate prevalence of dementia among priority groups, contributing to goals 1 and 3 of this plan. |
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| Level of investment | Low–medium: The level of investment is dependent on the type of activity being undertaken. Development of new methodologies using existing data would require low investment, while new studies would require more investment. |
| Timeframe | Short–medium |
| Responsible stakeholder | Academic researchers; organisations with experience in collecting data among priority population groups; AIHW (for linked data projects) |
| Progress | In November 2024, the AIHW hosted a workshop that focused on improving dementia prevalence and incidence data, nationally and among priority population groups. Workshop attendees included representatives from relevant government agencies involved in monitoring Australia’s health with epidemiological and clinical researchers with expertise in dementia. Activity 3h has been developed as a result of this workshop and may contribute to the outcomes of this activity for some priority populations including First Nations people, people from CALD backgrounds and people living with younger onset dementia. Data on childhood dementia are lacking, and further work is needed to identify and develop data sources and methods. |
Activity 3f: Develop a Regional Insights portal of dementia data for local areas
A Regional Insights portal for dementia would bring together dementia statistics across a range of topics at a local level, allowing users to easily access and compare dementia statistics for geographic areas. This would include estimates of dementia prevalence, health and aged care service use and other key statistics. This would be a similar design to the Regional Insights for Indigenous Communities (RIFIC) website. This activity supports the National Health Reform Agreement commitment to regular reporting on services in regional, rural, and remote communities.
Consideration would be needed on how to best report dementia statistics across a range of topics at a local level and the quality of the data by smaller geographies, and among priority population groups. For example, for data on dementia among First Nations people this could be the incorporation of dementia data into the existing RIFIC website. This would support Priority Reform Four: Shared access to data and information at a regional level in the Closing the Gap Implementation Plan 2024. However, sufficient data needs to be available at the local level for this population group.
The NCMD released the report, Geographical variation in health service use by people living with dementia in 2023. Work for this activity could build on this report by expanding the topics reported on and providing data for smaller geographies and populations to incorporate into a Regional Insights portal.
| Outcome | Easy access to local geographic and comparator dementia statistics |
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| Level of investment | Medium–high: Investment in the development and usability of a web-based portal is required. Maintenance of this website over several years would lead to this activity overall being a high investment activity. |
| Timeframe | Medium |
| Responsible stakeholder | AIHW NCMD; academic researchers; organisations with experience in collecting data among priority population groups |
| Progress | Not started |
Activity 3g: Assess impact of dementia coding changes in ICD-11 when incorporated in the Australian health system
The International Classification of Diseases (ICD) is a global health classification standard which forms the basis for the recording of health data and production of health-related statistics. The ICD is revised every 10–20 years to ensure its currency and utility. ICD-11 represents a significant advance on the 10th revision of ICD, currently in use in Australia and internationally. In addition to updated scientific content, ICD-11 has been developed for use in digital environments and is linked to other relevant classifications and terminologies (AIHW 2023). The Australian ICD-11 Task Force was established in 2022 to develop a roadmap of activities to inform the decision towards the implementation of the ICD-11 in Australia (AIHW 2023).
This activity will monitor the implementation of ICD-11 in Australia and assess its impact on dementia coding across a range of contexts, including morbidity and mortality coding, as well as adaptations for clinical use in primary care, specialty care and research.
| Outcome | Known impact of coding changes for dementia in ICD-11 and more rapid adaptations to existing routine monitoring of dementia using ICD coded data |
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| Level of investment | Low |
| Timeframe | Short; Impact assessment can only commence after the ICD-11 has been implemented in Australia |
| Responsible stakeholder | AIHW |
| Progress | The AIHW is leading Australia’s implementation of ICD-11 in Australia and has an ongoing function to assess its impact on existing coding. AIHW assessment of the impact of ICD-11 codes regarding dementia has shown increased granularity in several dementia codes and subtypes compared to previous ICD versions. ICD-11 also enables postcoordination of contextual elements of dementia such as information on severity, onset and behavioural or psychological disturbances. ICD-11 also introduces new codes including dementia due to Down syndrome and dementia due to injury to the head which may support future research in these areas where data is currently lacking. Childhood dementia reporting relies significantly on ICD codes, yet only 20% of childhood dementia disorders have a specific ICD-10 code (Childhood Dementia Initiative 2025). While ICD-11 does not include codes for all childhood dementias, there are an increased number of codes for rare conditions. Post-implementation, this activity can assess which ICD-11 codes, postcoordination such as time in life, and data sources could support identification of childhood dementia. The impacts of these changes will need to be assessed once ICD-11 has been incorporated into the Australian health system. |
Activity 3h: Improve national dementia prevalence estimates using linked data
Current national estimates of dementia prevalence are reliant on data that are out of date, out of context, or are self-reported. Better data are critical to enable evidence-based decision making to plan, resource and evaluate services, initiatives and programs required to support people living with dementia.
This activity was developed from discussions at the AIHW Dementia Data Workshop (described in activity 3c) and preliminary findings from activity 3d. The activity aims to improve the AIHW’s dementia prevalence estimate by using statistical techniques which focus on estimating the ‘missing’ or ‘undercount’ of cases, as not all people living with dementia will have a record of dementia in available data.
Statistical techniques to estimate undercounts are increasingly used in population health monitoring where population samples and case ascertainment are often incomplete. These methods have been used to estimate dementia prevalence in small study populations in Australia, and internationally at sub-national and national levels.
This activity will endeavour to include dementia prevalence estimates for priority groups including people living with younger onset dementia and First Nations people.
| Outcome | Improved dementia prevalence estimates for Australia, goal 1 of this plan. |
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| Level of investment | Medium |
| Timeframe | Short |
| Responsible stakeholder | AIHW NCMD as a Dementia Data Partnership Project |
| Progress | As part of a Dementia Data Partnership Project, the University of Queensland are exploring undercount methods to improve estimates of dementia prevalence in Australia using linked Census, hospitals and aged care data (see activity 3d). Results are expected for public release in 2027. |
Monitoring the number of people living with dementia (prevalence) and the number of new cases of dementia each year (incidence) is required for policy development and service planning for health and aged care systems. Monitoring incidence over time indicates if the rate of diagnoses is increasing, decreasing or stable and whether certain population groups are more affected than others. However, this is difficult given the challenges of obtaining a timely diagnosis and lack of national general practitioner (GP) and specialist data with diagnostic information. See Timeliness of dementia diagnosis and Dementia diagnosis and management for more information.
Addressing the data gap and improving data
There is no single authoritative data source for deriving dementia prevalence in Australia, leading to varying estimates of how many people in Australia have dementia. Estimating dementia incidence is difficult because dementia is a gradual evolution of signs and symptoms rather than an acute event, and incidence requires information such as date of diagnosis and whether a diagnosis was made close to symptom onset (AIHW 2024). There is no comprehensive source of information on dementia diagnosis date, meaning that dementia incidence is currently unmeasurable. National data on dementia incidence would also facilitate the estimation of dementia survival rates in Australia, which are currently not well understood. Accurate information on the number of Australians living with, and dying from, dementia in Australia is critical for monitoring trends and informing dementia policy and service planning (AIHW 2025). Better data are also needed for the prevalence of different dementia types (for example, Alzheimer’s disease, vascular dementia) and severities, as well as people with mild cognitive impairment.
The Australian Dementia Network (ADNeT) Registry, with its goal to register all Australians newly diagnosed with either dementia or mild cognitive impairment (ADNeT 2023), may be a future source of data that can contribute to estimates of dementia incidence at the population level. The ADNeT Registry is described in further detail at Dementia diagnosis and management.
Existing epidemiological studies on healthy ageing, especially when linked with existing administrative data that enable identification of people living with dementia, could also inform better estimates of dementia prevalence and incidence. For example, the Sax Institute’s Analysis of Population Traits and Risk Factors (ADAPTOR) study already links longitudinal data from over 250,000 participants from the 45 and Up Study with data on their use of hospitals, GPs, health services and prescription medication. Adding cognitive measures to existing studies could improve measures of dementia prevalence and incidence in Australia. There are challenges with this approach, as many existing surveys use volunteers which are not representative of the general population, where dementia risks and prevalence may be greater in those not participating in voluntary surveys (Brayne and Moffitt 2022).
Bringing together disparate data sources through data linkage would also help overcome some of the limitations associated with estimating the prevalence of dementia in Australia. Linked administrative data sets are currently being used to monitor dementia, and methodologies could be developed and refined using linked data to model estimates of dementia prevalence in Australia. However, data linkage is dependent on the capture of dementia and the quality of information provided in the individual data sets. At present, improvements are needed in available data sets and more types of data linked together. For dementia, available national data often capture people who have used a health, aged care or other type of support service, or people who died with a record of dementia, which skews towards capturing people who access services and/or who have more advanced dementia. Therefore, improvements in existing population-based studies and national surveys, or the development of new studies are needed to inform the estimation of dementia prevalence and mild cognitive impairment in Australia.
ADNeT (Australian Dementia Network) (2023) The Australia Dementia Network Clinical Quality Registry, ADNeT website, accessed 24 May 2023.
AIHW (Australian Institute of Health and Welfare) (2025) Dementia in Australia, AIHW, Australian Government, accessed 15 October 2025.
AIHW (2023) International classification of diseases revision, AIHW website, Australian Government, accessed 31 July 2023.
Brayne C and Moffitt TE (2022) ‘The limitations of large-scale volunteer databases to address inequalities and global challenges in health and aging’, Nature Aging, 2(9):775–783, doi:10.1038/s43587-022-00277.
Childhood Dementia Initiative (2025) Running Blind: Data gaps in childhood dementia healthcare, Childhood Dementia Initiative website, accessed 11 August 2025.