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. 2025 Jul 23;44(3):e70068. doi: 10.1111/ajag.70068

Older Aboriginal and Torres Strait Islander populations living with dementia: State and territory scenario‐based projections into the future

Joanne Luke 1,✉, Jeromey Temple 1, Tom Wilson 1, Ruth Williams 1, Sean Taylor 2, Dina LoGiudice 3
PMCID: PMC12285214  PMID: 40698753

Abstract

Objective

To produce plausible estimates of the number of Aboriginal and/or Torres Strait Islander people living with dementia within Australia disaggregated by state and territory to mid‐century.

Methods

The Wilson–Grossman variation of the Hamilton–Perry projection model was used to prepare state and territory projections of the Aboriginal and/or Torres Strait Islander population, 2021–2051. Data from the Australian Bureau of Statistics Census (2021) and Australian Institute of Health and Welfare 2021 were used to estimate the number of people living with dementia 2021–2051.

Results

From 2021 to 2051, the Australian Aboriginal and/or Torres Strait Islander population is projected to grow across all states and territories. By 2051, there will be an increasing number and proportion of the population aged over 45, 65 and 80 years, with this increase varying by jurisdiction. This pattern of ageing will see an increase in the number of Aboriginal and/or Torres Strait Islander people living with dementia, regardless of assumptions about future dementia prevalence. This increase will vary in magnitude by juristiction, doubling in the Northern Territory and increasing more than fivefold in the Australian Capital Terrritory, New South Wales, Tasmania and Queensland. Sensitivity analyses of alternative dementia scenarios produce highly similar results.

Conclusions

Between 2021 and 2051, the estimated number of Aboriginal and/or Torres Strait Islander people living with dementia is projected to increase. Combined with regional demographic variations, this trend highlights the urgent need for targeted responses at both local and national levels.

Keywords: ageing, Australian Aboriginal and Torres Strait Islander peoples, dementia, Indigenous peoples

Policy Impact.

This study found that the Aboriginal and Torres Strait Islander population living with dementia will increase by mid‐century across all Australian states and territories. Our findings highlight the importance of having spatial data at the regional level to effectively plan health, social and aged care for this diverse population.

1. INTRODUCTION

Dementia is a leading cause of death in Australia, as in many countries worldwide. 1 At a time when many populations are ageing, an understanding of the prevalence, drivers and futures of people living with dementia is critical, not only from an epidemiological perspective but also to inform the future planning and provision of medical, social and aged care services to this growing population. 2 For Aboriginal and Torre Strait Islander populations, Australian government policy frameworks highlight the importance of planning for and current limitations with existing health‐care provision and services. 3 , 4

The Australian Institute of Health and Welfare (AIHW) projects that the number of people living with dementia will increase twofold by mid‐century. 5 However, there remains a paucity of spatial information and modelling on the prevalence of dementia now and into the future among Aboriginal and Torres Strait Islander people. 6 The three most recent dementia cohort studies involving Aboriginal and Torres Strait Islander populations have provided a strong evidence base to suggest that prevalence rates of dementia are up to 3–5 times higher than in non‐Indigenous Australians. 7 , 8 , 9 Recent national level modelling indicates that the population of older Aboriginal and Torres Strait Islander people living with dementia is projected to increase significantly by mid‐century, driven in part by population growth and ageing. 10 Further, recent national estimates suggest that the population of older Aboriginal and Torres Strait Islander people aged 45 years and older will increase by nearly 170% by mid‐century. Notably, the population aged 85 years and over is projected to grow at an even faster rate, highlighting the need for age‐specific planning and support. 11

Despite this recent research and the implications for service planning and provision, no study has considered the future ageing of Aboriginal and Torres Strait Islander people living with dementia across Australia's states and territories. A geographic understanding of dementia futures is important for health‐care provision, caring and planning. Our paper seeks to address this gap by (i) examining structural and numeric ageing of the Aboriginal and Torres Strait Islander population in Australian states and territories from 2021 to 2051, and (ii) understanding the growth of this population living with dementia under various prevalence scenarios.

2. METHODS

2.1. Ethical considerations

Ethics approval for this study was granted by the University of Melbourne Human Research Ethics Committee (Approval number: 2023‐25631‐42542‐4).

This research was conducted by Aboriginal, Torres Strait Islander and non‐Indigenous researchers in accordance with NHMRC guidelines 12 and corresponds with priorities identified by Aboriginal and Torres Strait Islander communities. 13

The Hamilton–Perry cohort projection model was used to prepare state and territory projections of the Aboriginal and/or Torres Strait Islander population by sex and age group from 2021 to 2051. 14 , 15 As described elsewhere, 16 this is a simplified model that requires minimal input data and is therefore well‐suited to situations in which the necessary data for standard projection techniques are unavailable or unreliable. In the case of the Aboriginal and/or Torres Strait Islander population, only some demographic data are needed to prepare projections when a standard multistate cohort‐component model is available, and there are quality limitations affecting available births, deaths and migration data. For a comparison of methods used to project the Aboriginal population under different data environments, readers are directed to Wilson et al. 16

Specifically, the Hamilton–Perry model projects a cohort population forward in 5‐year projection intervals by adding or subtracting cohort population change—using Cohort Change Ratios (CCRs) and Cohort Change Differences (CCDs). Projection calculations are repeated for as many 5‐year projection intervals as required, with projected populations from one interval becoming the start‐of‐interval populations for the next interval.

Projections of the number of people living with dementia were calculated by applying dementia prevalence rates to projected populations by sex and age group. Dementia prevalence rates for Aboriginal and/or Torres Strait Islander people were estimated from national prevalence rates for 2021 published by the AIHW 5 and 2021 Australian Bureau of Statistics (ABS) Census counts of people reporting dementia. 17 Due to uncertainty surrounding the true levels of dementia in the population, we estimated two sets of prevalence rates. The first set is based on the national AIHW estimates, with the census data used to estimate ratios to national rates. Because of noisy patterns in rates at young and middle adult ages due to relatively few people with dementia, the Census‐based ratios were only calculated from dementia amongst the population aged over 75 years.

The second set of prevalence rates is based on Census counts of dementia. Smoothing over age was again applied due to small numbers. We took the census‐based rates for the national Aboriginal and/or Torres Strait Islander population and applied the ratio of Aboriginal and/or Torres Strait Islander state rates for ages over 75 years to the national Indigenous rates for ages over 75 years.

2.1.1. Input data and projection assumptions

Aboriginal and/or Torres Strait Islander Estimated Resident Populations (ERPs) by sex and 5‐year age group for 2011, 2016 and 2021 were obtained from the ABS. 16 , 17 , 18 , 19 , 20 Cohort Change Ratios and CCDs were calculated for both 2011–2016 and 2016–2021 periods, averaged over the two periods and smoothed across age to reduce noise.

For both sets of dementia prevalence rates, three future scenarios were formulated. These were as follows:

  • Constant: Prevalence rates estimated for 2021 were assumed to remain unchanged.

  • Decreasing: Rates were assumed to decline by 1% per year.

  • Increasing: Rates increase by 1% per year.

These scenarios reflect considerable uncertainty about the future trajectory of dementia prevalence among the Aboriginal and/or Torres Strait Islander population. Some international studies report declines in prevalence over time, 21 , 22 though a few reported increases. 23

3. RESULTS

3.1. Aboriginal and/or Torres Strait Islander population projections, 2021–2051

Table 1 displays projected indices of numerical and structural population ageing to mid‐century, including a breakdown by age. Baseline estimates for 2021 reveal that approximately one in five Aboriginal and/or Torres Strait Islander people living in Australia were aged over 45 years, with a majority of those living across the states of New South Wales (NSW) (35%), Queensland (QLD) (27%) and Western Australia (WA) (12%). The age profile of the population varies by state, with Tasmania (TAS) having a slightly older population structure and the Australian Capital Territory (ACT) the youngest, while the Northern Territory (NT) had the smallest percentage of population over 80 years at 1%. Nationally, only 5% of the Aboriginal and/or Torres Strait Islander population was over 65 years and 1% over 80 years.

TABLE 1.

Aboriginal and/or Torres Strait Islander population count by state and territory, 2021–2051.

NSW VIC QLD SA WA TAS NT ACT AUST
2021
Population <45 260,817 61,235 212,388 40,518 93,472 25,120 59,006 7627 760,183
Population 45+ 78,729 17,463 60,836 11,565 26,565 8774 17,730 1917 223,579
Population 65+ 20,138 4313 14,273 2612 5675 2473 3416 401 53,301
Population 80+ 2878 587 1831 362 722 345 411 60 7196
Total 339,546 78,698 273,224 52,083 120,037 33,894 76,736 9544 983,762
% <45 77 78 78 78 78 74 77 80 77
% 45+ 23 22 22 22 22 26 23 20 23
% 65+ 6 6 5 5 5 7 5 4 5
% 80+ 1 1 1 1 1 1 1 1 1
2051
Population <45 661,028 155,704 445,552 82,830 169,914 44,874 59,680 15,032 1,634,614
Population 45+ 255,372 61,475 178,615 29,815 70,185 23,684 30,860 8038 658,044
Population 65+ 98,530 22,594 67,728 9982 23,553 10,528 8938 3306 245,160
Population 80+ 29,089 6258 18,314 2155 5159 3470 1559 1401 67,406
Total 916,400 217,179 624,167 112,645 240,099 68,557 90,540 23,070 2,292,658
% <45 72 72 71 74 71 66 66 65 71
% 45+ 28 28 29 27 29 35 34 35 29
% 65+ 11 10 11 9 10 15 10 14 11
% 80+ 3 3 3 2 2 5 2 6 3
(2021–2051) change
Population <45 400,211 94,469 233,164 42,312 76,442 19,754 674 7405 874,431
Population 45+ 176,643 44,012 117,779 18,250 43,620 14,910 13,130 6121 434,465
Population 65+ 78,392 18,281 53,455 7370 17,878 8055 5522 2905 191,859
Population 80+ 26,211 5671 16,483 1793 4437 3125 1148 1341 60,210
Total 576,854 138,481 350,943 60,562 120,062 34,663 13,804 13,526 1,308,896
% <45 −5 −6 −6 −4 −7 −9 −11 −15 −6
% 45+ 5 6 6 4 7 9 11 15 6
% 65+ 5 5 6 4 5 8 5 10 5
% 80+ 2 2 2 1 2 4 1 5 2
Population <45G 153 154 110 104 82 79 1 97 115
Population 45 + G 224 252 194 158 164 170 74 319 194
Population 65 + G 389 424 375 282 315 326 162 725 360
Population 80 + G 911 966 900 495 615 906 279 2235 837
Total G 170 176 128 116 100 102 18 142 133
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Note: G refers to the percentage growth rate over the time period 2021–2051.

Abbreviations: ACT, Australian Capital Territory; AUST, Australia (total across States and Territories); NSW, New South Wales; NT, Northern Territories; QLD, Queensland; SA, South Australia; TAS, Tasmania; VIC, Victoria; WA, Western Australia.

By 2051, there will be a threefold increase in the number of Aboriginal and/or Torres Strait Islander people 45 years and older nationally, owing to numeric ageing of the population. This proportional increase will see a 4.6‐fold increase in the population over 65 years and a 9.3‐fold increase in the population over 80 years. The extent and pattern of ageing is projected to vary by region. For example, although the NT and ACT are projected to have the greatest proportional increase in population aged over 45 years, for the NT, only 2% of the population will be over 80 years compared to 6% of the ACT population.

3.2. Estimated Aboriginal and/or Torres Strait Islander population living with dementia, 2021

Table 2 provides estimates of the Aboriginal and/or Torres Strait Islander population living with dementia in 2021 under two baseline prevalence rates considered for this study. Results demonstrated that there is poor harmonisation between AIHW and Census models in estimating the number of people living with dementia (6520 vs. 4454), their age (98% over 45‐year vs. 91%) and gender (60% female vs. 54%). However, both did show that the greatest proportion of people living with dementia was from NSW (33%) and QLD (31%). There were also regional differences in sex ratios, with the NT estimating a far greater proportion of women living with dementia with a sex ratio of approximately 3:1.

TABLE 2.

Estimated Aboriginal and/or Torres Strait Islander population living with dementia, 2021 (AIHW‐ and census‐adjusted scenario).

NSW VIC QLD SA WA TAS NT ACT AUST
AIHW‐adjusted prevalence
Males 966 157 851 124 250 99 115 15 2576
Females 1215 235 1142 230 587 142 371 23 3944
Total 2181 391 1992 353 837 242 486 38 6520
% AUST total 33 6 31 5 13 4 8 1 100
Total 45+ 2135 382 1942 344 813 237 471 36 6361
Total 65+ 1823 326 1636 287 680 204 385 30 5371
Total 80+ 817 144 687 129 302 90 166 14 2348
% Female 56 60 57 65 70 59 76 60 60
% 45+ 98 98 97 97 97 98 97 97 98
% 65+ 84 83 82 81 81 84 79 81 82
% 80+ 37 37 34 36 36 37 34 38 36
Census‐adjusted prevalence
Males 753 126 691 100 212 74 101 13 2069
Females 723 141 694 141 357 84 231 14 2385
Total 1476 267 1385 241 569 158 332 27 4454
% AUST total 33 6 31 5 13 4 8 1 100
Total 45+ 1356 243 1255 218 512 148 296 24 4052
Total 65+ 1029 183 922 160 373 115 210 17 3009
Total 80+ 434 76 363 68 154 48 85 8 1234
% Female 49 53 50 58 63 53 70 52 54
% 45+ 92 91 91 91 90 93 89 88 91
% 65+ 70 69 67 66 66 73 63 63 68
% 80+ 29 28 26 28 27 30 26 28 28
Ratio AIHW‐ to census‐adjusted estimates
Males 1.28 1.25 1.23 1.23 1.18 1.34 1.14 1.16 1.24
Females 1.68 1.67 1.64 1.63 1.65 1.68 1.61 1.62 1.65
Total 1.48 1.47 1.44 1.47 1.47 1.53 1.47 1.40 1.46
Total 45+ 1.57 1.58 1.55 1.58 1.59 1.60 1.59 1.53 1.57
Total 65+ 1.77 1.79 1.77 1.79 1.82 1.77 1.83 1.78 1.79
Total 80+ 1.88 1.90 1.89 1.89 1.96 1.88 1.96 1.87 1.90
% Female 1.14 1.13 1.14 1.11 1.12 1.10 1.10 1.16 1.13
% 45+ 1.07 1.07 1.08 1.07 1.08 1.05 1.08 1.10 1.07
% 65+ 1.20 1.22 1.23 1.22 1.24 1.16 1.25 1.27 1.22
% 80+ 1.27 1.29 1.32 1.29 1.33 1.23 1.34 1.33 1.30
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Abbreviations: ACT, Australian Capital Territory; AIHW, Australian Institute of Health and Welfare; AUST, Australia (total across States and Territories); NSW, New South Wales; NT, Northern Territories; QLD, Queensland; SA, South Australia; TAS, Tasmania; VIC, Victoria; WA, Western Australia.

3.3. Projections of the Aboriginal and/or Torres Strait Islander people living with dementia, 2051

Table 3 presents the projections for the Aboriginal and/or Torres Strait Islander population living with dementia by 2051, using the AIHW‐adjusted prevalence rates assuming scenarios of a constant, high and low trend in prevalence rates. In all three scenarios, the number of people living with dementia is expected to increase across all states and territories. Under constant trends where the prevalence rates for dementia remain unchanged from 2021 to 2051, the number of Aboriginal and/or Torres Strait Islander people living with dementia will increase 5.9‐fold nationally (from 6520 people to 38,285). Similarly, for estimates under both low and high prevalence trends, there will be a 4.3‐fold and 7.9‐fold increase, respectively. Table 4 replicated these analyses for the Census‐adjusted rates, again assuming a low, constant and high trend in prevalence rates. Under these three scenarios, findings are consistent with AIHW‐adjusted rates projecting a 3.8‐fold, 5.1‐fold and 6.9‐fold increase in the number of Aboriginal and/or Torres Strait Islander people living with dementia.

TABLE 3.

Projected Aboriginal and/or Torres Strait Islander population living with dementia, 2051 (AIHW‐adjusted).

NSW VIC QLD SA WA TAS NT ACT AUST
Constant
Males 6051 1168 5241 599 1282 540 270 233 15,383
Females 8316 1490 7125 894 2694 948 1124 310 22,902
Total 14,367 2659 12,366 1493 3976 1488 1394 542 38,285
% AUST total 38 7 32 4 10 4 4 1 100
Total 45+ 14,231 2632 12,243 1473 3929 1479 1376 539 37,902
Total 65+ 13,372 2450 11,439 1332 3589 1405 1217 518 35,323
Total 80+ 8848 1564 7239 734 2112 979 617 414 22,506
% Female 58 56 58 60 68 64 81 57 60
% 45+ 99 99 99 99 99 99 99 100 99
% 65+ 93 92 93 89 90 94 87 96 92
% 80+ 62 59 59 49 53 66 44 76 59
Constant (increment to 2021 constant base)
Males 5085 1012 4390 476 1032 440 155 218 12,807
Females 7101 1256 5984 664 2107 806 753 287 18,958
Total 12,187 2267 10,374 1140 3139 1246 908 505 31,765
Total 45+ 12,096 2249 10,301 1128 3116 1242 906 503 31,541
Total 65+ 11,549 2124 9803 1045 2910 1201 833 487 29,952
Total 80+ 8030 1420 6552 606 1811 889 451 400 20,158
High (increment to 2021 constant base)
Males 7202 1420 6224 685 1480 629 249 299 18,189
Females 10,011 1777 8477 977 3049 1138 1146 395 26,970
Total 17,213 3198 14,700 1662 4530 1767 1395 695 45,159
Total 45+ 17,075 3170 14,585 1643 4490 1759 1387 692 44,802
Total 65+ 16,227 2981 13,806 1511 4166 1692 1259 669 42,310
Total 80+ 11,126 1967 9084 863 2550 1231 666 545 28,032
Low (increment to 2021 constant base)
Males 3517 709 3032 320 700 300 85 157 8820
Females 4946 870 4137 432 1409 560 462 207 13,022
Total 8463 1578 7169 753 2108 861 546 364 21,842
Total 45+ 8408 1567 7128 747 2097 859 549 363 21,718
Total 65+ 8083 1489 6839 700 1980 837 517 353 20,797
Total 80+ 5737 1014 4676 415 1263 635 291 293 14,324
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Abbreviations: ACT, Australian Capital Territory; AIHW, Australian Institute of Health and Welfare; AUST, Australia (total across States and Territories); NSW, New South Wales; NT, Northern Territories; QLD, Queensland; SA, South Australia; TAS, Tasmania; VIC, Victoria; WA, Western Australia.

TABLE 4.

Projected Aboriginal and/or Torres Strait Islander population living with dementia, 2051 (Census‐adjusted).

NSW VIC QLD SA WA TAS NT ACT AUST
Constant
Males 4086 784 3568 420 913 349 208 141 10,469
Females 4448 822 3856 513 1487 500 645 154 12,424
Total 8534 1606 7424 933 2400 849 852 295 22,893
% AUST total 37 7 32 4 10 4 4 1 100
Total 45+ 8201 1540 7126 884 2290 829 813 288 21,973
Total 65+ 7306 1355 6295 749 1959 759 670 266 19,359
Total 80+ 4572 822 3762 394 1080 503 320 204 11,658
% Female 52 51 52 55 62 59 76 52 54
% 45+ 96 96 96 95 95 98 95 98 96
% 65+ 86 84 85 80 82 89 79 90 85
% 80+ 54 51 51 42 45 59 38 69 51
Constant (increment to 2021 constant base)
Males 3333 659 2877 320 702 275 107 128 8400
Females 3725 681 3162 373 1130 415 414 140 10,039
Total 7058 1339 6039 693 1831 691 520 268 18,439
Total 45+ 6845 1298 5871 666 1778 681 517 264 17,921
Total 65+ 6277 1172 5373 589 1586 644 460 249 16,350
Total 80+ 4138 746 3400 326 927 456 235 196 10,423
High (increment to 2021 constant base)
Males 4762 933 4125 467 1021 398 179 177 12,063
Females 5281 968 4511 552 1650 590 639 194 14,385
Total 10,043 1901 8636 1019 2671 988 819 371 26,448
Total 45+ 17,853 3310 15,272 1770 4792 1849 1561 705 47,110
Total 65+ 17,022 3125 14,519 1638 4473 1781 1433 682 44,672
Total 80+ 11,509 2035 9408 923 2698 1273 748 552 29,146
Low (increment to 2021 constant base)
Males 2274 455 1952 211 465 185 53 91 5687
Females 2572 468 2162 240 744 286 247 100 6819
Total 4846 923 4115 451 1209 471 299 191 12,505
Total 45+ 4719 899 4024 437 1185 466 306 190 12,226
Total 65+ 4384 821 3741 395 1079 447 286 180 11,333
Total 80+ 2953 533 2424 224 647 325 152 143 7402
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Abbreviations: ACT, Australian Capital Territory; AUST, Australia (total across States and Territories); NSW, New South Wales; NT, Northern Territories; QLD, Queensland; SA, South Australia; TAS, Tasmania; VIC, Victoria; WA, Western Australia.

At the state and territory level, projections generated using both AIHW and Census‐adjusted prevalence rates reveal that the magnitude of increase in people living with dementia will vary by region, as will the age and sex profiles of the population. Although both prevalence scenarios unanimously show a substantial increase in the number of Aboriginal and/or Torres Strait Islander people living with dementia across all jurisdictions, the NT is expected to have the smallest proportional increase (although still expected to more than double), while the ACT, Victoria (VIC), NSW, TAS and QLD are all projected to have an increase higher than the national (greater than a fivefold increase). Projections for both scenarios showed that by 2051, 70% of the Aboriginal and/or Torres Strait Islander population living with dementia will be from NSW and QLD, up from 64% in 2021.

Disaggregation at the state and territory level showed that despite an overall increase in the age of the population living with dementia across jurisdictions, the structural age of the population living with dementia will differ by jurisdiction, with the ACT's population predominantly over 80 years, while the NT population living with dementia will mostly be younger than 80 years.

4. DISCUSSION

A study by Temple et al. (2022) shows there is expected to be considerable growth in the number of Aboriginal and/or Torres Strait Islander people living with dementia in Australia by 2051. 10 However, this national aggregated data only provide a partial picture of dementia prevalence now and into the future for this culturally and geographically diverse population. A key contribution of this study is that it provides a more detailed spatial description of ageing and the demographic drivers of dementia at a state and territory level, allowing for a more targeted approach to dementia prevention and management.

Data presented here show that regardless of assumptions made about future dementia prevalence, from 2021 to 2051, the number of Aboriginal and/or Torres Strait Islander people living with dementia will more than double across all states and territories owing to the effects of numeric and structural ageing. The magnitude of this increase is expected to vary by state and territory and appears to follow a pattern of life expectancy. For example, the NT, the territory with the youngest age structure and known life expectancy (65.6 years for males and 69.4 years for females), is projected to have the smallest increase in dementia numbers. 24 Conversely, in the eastern states and territories of the ACT, VIC, QLD, TAS and NSW, where larger proportions of the populations are projected to be over 80 years, there will be a more than fivefold increase in the number of people living with dementia if prevalence rates remain constant.

The patterns and magnitude of structural and numeric ageing across all states and territories project an overall fourfold increase in the population over 65 years, and an eightfold increase in population over 80 years. These demographic shifts mean that the needs of people living with dementia will place increasing pressure on an already overstretched health and aged care system. 25 We currently know that the Australian health, social, and aged care system is not meeting the current needs of Aboriginal and Torres Strait Islander people with dementia and their families. 26 , 27 , 28 It is a system based on Eurocentric, individualistic and often privatised models of care that were not designed with Aboriginal and Torres Strait Islander populations in mind. 27 , 29 , 30 Given this, many Aboriginal and Torres Strait Islander people have a preference to use Aboriginal and/or Torres Strait Islander community‐controlled organisations or specialist programs and services co‐designed or delivered in partnership with these organisations and communities. 31 , 32 The culturally safe, trauma‐informed and holistic model of care underpinning these services is appropriate and acceptable for Aboriginal and/or Torres Strait Islander people. 33 In recognising this preference, Aboriginal and/or Torres Strait Islander community‐controlled organisations must be adequately resourced to meet needs projected here.

We currently know there are shortages across the Australian health, social and aged care workforce, which has only been exacerbated by the recent COVID‐19 pandemic. 34 To meet the growing future demand for care for people with dementia, their carers and families, there needs to be resourcing and investment to maintain and build a trained and culturally competent workforce. Increased training and development opportunities to build the Aboriginal and Torres Strait Islander workforce are key to this. 34 , 35 , 36

There is no one‐size‐fits‐all approach to improving dementia care, with access and workforce challenges that are specific to each urban, regional and remote settings. Any broad effort to reduce dementia nationally must also be complemented by co‐ordinated community and state‐based approaches. We know that responding to dementia in Aboriginal and Torres Strait Islander settings is complex given the fragmented nature of the Australian care system, where different components of the health, social and aged care system fall under the responsibility of different commonwealth and state and territory jurisdiction. 25 , 26 It is further complicated by the geographic spread and intra‐diversity of the population, which includes populations with additional recognised needs such as the Stolen Generations members. 26 , 27 In the coming years, a whole‐of‐service response will be needed to improve the journey of Aboriginal and Torres Strait Islander people as they navigate Australia's health, social and aged care systems. This response must support individuals across the full continuum of care—from prevention, diagnosis and screening to management and end‐of‐life support. These responses should be guided by frameworks for quality and culturally safe care such as the Good Spirit Good Life Framework for healthy ageing for Aboriginal and Torres Strait Islander people. 37

In terms of dementia prevention, we found that a 10% reduction in the AIHW‐adjusted prevalence rates between 2021 and 2051 could prevent around 10,000 dementia cases (6000 using Census adjusted prevalence rates) amongst Aboriginal and Torres Strait Islander people. This potential reduction would translate to immeasurable benefits for Aboriginal and Torres Strait Islander families and communities and place fewer demands on Australian health, social and aged care systems. Prevention strategies will also need to focus on strengthening awareness and knowledge not just of those at risk or living with dementia, but the whole community and workforce. 29 Resources developed by and in collaboration with Indigenous organisations and communities have demonstrated prior effectiveness in raising community awareness about dementia. 38

To realise a reduction in dementia prevalence requires targeted action to prevent and manage modifiable dementia risk factors specific to this population. These include those outlined in the 2020 Lancet Commission on Dementia Prevention, Intervention and Care report 39 of obesity, physical inactivity, smoking, low education, diabetes mellitus, hypertension, depression, hearing impairment, alcohol consumption, social isolation and traumatic brain injury. These World Health Organization identified risks have been found to attribute to 35% of dementia burden for a Torres Strait Islander population. 40 , 41 The evidence base on dementia prevention underscores the importance of responding to modifiable ‘risks’ across the life‐course, which in the Australian and international context includes consideration of the impacts of ongoing colonisation and structuralised racism. 33 , 42 , 43 However, it must be acknowledged that the biggest risk of ‘age’ is non‐modifiable, so a vast majority of dementia projected for this population just cannot be prevented. Consequently, the coming years are expected to see an increasing demand for health, social and aged care services, and the Australian system must be prepared to meet the cultural, social and emotional well‐being needs of Aboriginal and Torres Strait Islander populations.

4.1. Limitations

While the Hamilton–Perry model is simple to implement and frequently produces quality short‐term forecasts, it is important to note a few limitations. These include: being unable to produce projections on births, deaths and migration and identify change, as these processes are not explicitly modelled; inability to formulate precise projection assumptions and scenarios based on those components; difficulties in constraining projections for higher geographies; and conceptual limitations due to demographic processes not being calculated as a function of populations‐at‐risk.

High‐quality data on dementia prevalence is instrumental to supporting evidence based decision‐making. 44 , 45 Our modelling revealed discrepancies between using AIHW and Census adjusted prevalence rates models and is illustrative of the practical complexity of determining and documenting dementia prevalence now and into the future. 10 If we are to better understand dementia prevalence for Aboriginal and Torres Strait Islander populations, then we need to improve data quality in existing systems, establish larger representative cohort studies, and strengthen screening and diagnosis. Screening and diagnosis can be strengthened by the application of culturally appropriate diagnostic tools, increased support to clinicians, and the universal integration of dementia screening into existing tools (e.g. Medicare 715 Health Assessments). 25 , 45

The 2021 Census allowed all respondents to select from three response options for the sex question: male, female and non‐binary sex. A limitation of our analysis is that we report sex as a male/female binary owing to limitations relating to underlying ERP (estimated resident population) data used and cell size limitations from the census side.

5. CONCLUSIONS

Clearer projections of future dementia pathways for Aboriginal and Torres Strait Islander populations across the states and territories will come when the Australian data environment and collection improves. Until then, this study provides us with population estimate scenarios of the number of Aboriginal and Torres Strait Islander people living with dementia at state and territory level for the years 2021–2051. These scenarios reveal that regardless of dementia prevalence rates applied (AIHW or Census) or conditions (increasing, constant or decreasing prevalence), all scenarios universally project that there will be a substantial increase in the number of Aboriginal and Torres Strait Islander people across Australia living with dementia, and that this will vary in magnitude by region. Consideration of these geographic patterns of dementia at a state and territory level will facilitate more targeted and co‐ordinated prevention and management approaches.

FUNDING INFORMATION

This research was supported by the Australian Research Council Centre for Excellence in Population Ageing Research (CE1101029) and the National Health and Medical Research Council Call for Research into Healthy Ageing of Aboriginal and Torres Strait Islander Peoples (grant no 1170403).

CONFLICT OF INTEREST STATEMENT

No conflicts of interest declared.

ACKNOWLEDGEMENTS

The authors have nothing to report. Open access publishing facilitated by The University of Melbourne, as part of the Wiley ‐ The University of Melbourne agreement via the Council of Australian University Librarians.

Luke J, Temple J, Wilson T, Williams R, Taylor S, LoGiudice D. Older Aboriginal and Torres Strait Islander populations living with dementia: State and territory scenario‐based projections into the future. Australas J Ageing. 2025;44:e70068. doi: 10.1111/ajag.70068

DATA AVAILABILITY STATEMENT

Data sharing not applicable to this article as no datasets were generated or analysed during the current study.

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Data Availability Statement

Data sharing not applicable to this article as no datasets were generated or analysed during the current study.

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