Older Australian Twins Study (OATS)
Older Australian Twins Study
Brain MRI, amyloid PET for some, and repeated cognitive and medical assessments of older twins and siblings, which separate genetic from environmental influences on brain ageing and dementia. 623 people aged 65 and over in Australia, 207 with PET. Released through Dementias Platform Australia.
Overview
The Older Australian Twins Study (OATS) is a longitudinal study of older twins run by the Centre for Healthy Brain Ageing (CHeBA) at UNSW Sydney, with sites in New South Wales, Queensland and Victoria. Comparing identical and non-identical twins lets it separate genetic from environmental influences on brain ageing, cognitive decline and dementia. Participants were recruited through the Australian Twin Registry and seen up to six times until assessments stopped in 2021. Researchers apply for the data through Dementias Platform Australia (DPAU).
Composition
The baseline cohort has 623 people aged 65 or older: 161 identical and 124 non-identical twin pairs, one identical triplet set, 27 single twins and 23 siblings who are not twins. CHeBA reports 450 at the second assessment (2009 to 2013) and 392 at the third (2012 to 2016); a 2013 paper gives 426 for wave 2. By 2017 the study had obtained 1,126 MRI brain scans. An amyloid PET sub-study scanned 207 participants in New South Wales and Victoria between 2012 and 2017. Assessments also cover cognition, psychiatric and cardiovascular health, blood biochemistry and genetics.
Acquisition
The SWI used for microbleed work was acquired on a 1.5 T Siemens MAGNETOM Avanto with a 3D gradient-echo sequence (TR 38 ms, TE 30 ms, flip angle 15 degrees, 1.5 mm slices). Scanners and protocols for the other MRI sequences and sites are not summarised in the sources used here.
Annotations
Hassanzadeh et al. (2025) had two radiologists independently mark cerebral microbleeds on an OATS SWI subset and report 54 microbleeds (23 scans in the dataset section, 24 in the results). DPAU lists MRI microbleeds as an OATS data category; whether it holds these labels is not stated.
Known limitations
- Wave sizes differ between the CHeBA website and the 2013 paper.
- The number of participants with each MRI sequence, and the sex and age distribution, are not published in the sources used here.
- Access costs an application fee, is limited to an approved project, and raw MRI is not suited to DPAU's analysis environment.
Cohort
Aggregate numbers from the sources below. Bars are relative to the 623 subjects.
Age
from 65
No age bins reported.
Abstract in Sachdev et al. 2013, International Review of Psychiatry (OATS cohort update)
Contrast / sequence
ScansGroups can overlap
- Susceptibility-weighted 23
Section 3.1.3 in Hassanzadeh et al. 2025, NeuroImage Clinical, cerebral microbleed recognition in GRE and SWI (PMC12410576)
License and access
Our reading of the license, not legal advice. Before you use the data, read the original license and confirm that your use is allowed. We take no responsibility for how you use a dataset. Full disclaimer
A research proposal is reviewed and approved
Dementias Platform Australia (DPAU) Data Access Agreement
Access for bona fide researchers to the cohorts hosted by Dementias Platform Australia at UNSW, after an application reviewed by DPAU and each contributing study, with ethics approval and fees. Data may be used only for the approved project, normally inside the DPAU analysis environment, may not be copied or distributed, and results may be used for commercial gain only with approval of every contributing study. Publications go to DPAU and the studies 30 working days before submission.
Application fees apply, and the OATS Governance Committee reviews each request. The DPAU analysis environment is built for tabular data, not raw imaging; other MRI data are requested with details in the application.
What you can do
- Conditional
- Not stated
- Not stated
- Conditional
- Conditional
What you can share
- No
- Conditional
- Share trained models Not stated
What you must do
- Yes
- Share alike No
- Yes
- Conditional
- Yes
- Conditional
- Conditional
- Conditional
Limits
- Yes
- No
Commercial license: Not stated No commercial license offer is published. Commercial gain from results needs approval from every contributing study.
Citation
Sachdev PS, Lammel A, Trollor JN, et al. A comprehensive neuropsychiatric study of elderly twins: the Older Australian Twins Study. Twin Research and Human Genetics 12(6), 573-582 (2009). doi:10.1375/twin.12.6.573
Sources
Every number on this page comes from one of these documents. Each chart names the table or page it is taken from. The raw numbers are in stats.csv.
- Sachdev et al. 2009, Twin Research and Human Genetics (OATS methodology) paper
- Sachdev et al. 2013, International Review of Psychiatry (OATS cohort update) paper
- Older Australian Twins Study page, CHeBA, UNSW website
- UNSW news, Findings from the Older Australian Twins Study (December 2017) website
- Hassanzadeh et al. 2025, NeuroImage Clinical, cerebral microbleed recognition in GRE and SWI (PMC12410576) paper