Social Determinants of Health in Ageing and Dementia
Exploring how social and structural factors shape brain health, with a focus on equity in cognitive ageing and dementia prevention.
The Social Determinants Research Group explores the social determinants of health in ageing and dementia. We investigate how social and structural conditions - where people are born, live, work, and age - shape brain health, cognitive ageing, and dementia risk.
Our work is grounded in a commitment to brain health equity, aiming to generate evidence that informs population-level strategies for promoting brain health and preventing dementia, guided by the lived experiences and values of diverse communities. Social determinants of health encompass factors such as education, healthcare access, housing stability, social support, economic security, and environmental conditions. Current evidence suggests that up to 45% of dementia risk is linked to modifiable factors, many of which are socially and structurally determined, ranging from social isolation and excessive alcohol use to limited early-life education and air pollution.
Our group focuses on emerging and underexplored determinants of dementia risk, including climate vulnerability, social mobility, food environments, discrimination, digital exclusion, access to nature, culturally safe healthcare, and gendered life course roles. At the core of our mission is a shift in perspective: from viewing brain health as an individual responsibility to recognising it as a collective right.
Our methodology
Positioned at the intersection of research, policy and practice, we strive to improve brain health outcomes in Australia and contribute to global solutions through international collaborations.
Social determinants of health encompass a broad range of factors, including access to education and healthcare, housing stability, social support, economic security, and environmental conditions. Current evidence suggests that up to 45% of dementia risk is linked to modifiable factors - many of which are socially and structurally determined. These include both factors that are influenced by context, such as social isolation and excessive alcohol use, and direct exposures, such as limited educational attainment in early life or air pollution.
Our group is particularly focused on emerging and underexplored determinants of dementia risk, including:
- climate vulnerability
- social mobility
- food environments
- discrimination
- digital exclusion
- access to nature
- culturally safe health care
- gendered life course roles.
At the core of our mission is a shift in perspective: from viewing brain health as an individual responsibility to recognising it as a collective right. We advocate for framing brain health as a public good - shaped by policy, community investment and structural change.
Team
- Group members
- Students
- Projects
- Publications
Group members
Students
- Xinyi Yu (PhD, Social Determinants of Ageing and Dementia in the Australian Context)
- Dylan Vo (Honours, Social connections and white matter changes in ageing - A longitudinal analysis of the Sydney Memory and Ageing Study)
- Jenny Chau (Honours, Social connections and risk for cardiovascular disease - A longitudinal analysis of the Sydney Memory and Ageing Study)
- Harriet Fay (Honours, Who benefits most? Investigating baseline dementia risk and age group as moderators of cognitive outcomes in the Maintain Your Brain trial)
- Manasi Somani (ILP, Does the co-occurrence of low social engagement and anxiety increase dementia risk? A longitudinal analysis in the Sydney Memory and Ageing Study)
Projects
Epidemiology
Social Frailty Index
Identifying and addressing social frailty is critical for early detection of dementia risk and improving health outcomes in older adults. This project focuses on understanding social frailty in older adults, which refers to vulnerability caused by the loss of meaningful social connections. The aim of this project is to evaluate and improve existing tools for measuring social frailty in older Australians to better identify those at risk of dementia.
Education, occupational complexity, wealth and dementia
Understanding how education, occupation, and socioeconomic status shape dementia risk across global contexts is essential for developing equitable prevention strategies. Education is a key modifiable risk factor for dementia, with higher educational attainment linked to lower dementia risk. Socioeconomic status (SES) and wealth also enhance cognitive reserve and improve access to healthcare and healthy lifestyles, with their interactions potentially varying between high-income and low- to middle-income countries. This study aims to explore how education, occupation, and SES together influence dementia risk across different economic settings.
Associations of neighbourhood environments with cognitive health, mental health and mortality
The neighbourhood environment, including factors such as green spaces, blue space, access to amenities, traffic, and pollution, plays a role in healthy ageing and dementia risk. Our group leads various projects on neighbourhood environment attributes and cognitive health, brain ageing, and dementia as well as depressive symptoms and mortality.
The impact of social isolation on healthy ageing: Exploring the role of the HPA axis and inflammation pathways
We know that social isolation is linked to increased dementia risk, but the mechanism remains uncertain. We will explore whether social isolation leads to declining brain health via depression or via chronic inflammation. To do this, we will bring together data from multiple cohort studies of ageing from around the globe, via Cohort Studies of Memory in an International Consortium (COSMIC).
How much dementia risk is explained by social determinants in Australia?
Our group is examining how much dementia risk is explained by structural and social determinants of dementia, such as housing, education, socioeconomic status, and environmental exposures, leveraging cohort data as well as large-scale public data sets administered by the Australian Bureau of Statistics (ABS). This line of work is partially supported by an Ageing Futures Institute (AFI) Seed Grant 2025 to explore this research question in the LINDA study.
Social frailty and mortality
Understanding how social frailty predicts long-term mortality helps identify vulnerable older adults and guide interventions that support healthy ageing.
This study examines the role of social frailty, a condition marked by factors such as reduced social resources, low engagement in social activities, and feelings of loneliness, in predicting long-term mortality risk among older adults. We also assess whether these associations differ by sex and level of education, two key social determinants of health. Understanding these patterns can help identify vulnerable subgroups and inform targeted interventions to promote healthy ageing across diverse populations.
Food security and healthy ageing
Food insecurity is a growing global issue that compromises nutrition and increases the risk of chronic disease and dementia in older adults. Food insecurity affects 57% of individuals in low- and middle-income countries and 11% in high-income countries. Food insecurity is associated with higher odds of dementia and poor cognitive outcomes, impacts overall health through nutrient deficiencies and low-quality diets, and can contribute to obesity, diabetes, and hypertension. Chronic stress from food insecurity may further exacerbate these health problems, particularly among disadvantaged populations. The study will assess the relationship between childhood food insecurity and overall health outcomes, including cognitive and physical well-being, in older adults across high- and low-income countries.
The role of AI companions in aged care facilities to reduce loneliness
In partnership with Leigh Place Aged Care in Roselands, Dr Suraj Samtani is leading a 5-week pilot study to see if co-designed artificial intelligence (AI) companions can reduce loneliness and improve well-being in residential aged care.
Social determinants of health and cognitive outcomes in the Maintain Your Brain trial
This study will examine whether individual-level social determinants of health (education, occupational status, migration status) and structural-level determinants (area-based socioeconomic deprivation) are associated with baseline dementia risk and cognitive performance, and whether they moderate MYB’s intervention effects on cognitive functioning and secondary outcomes (e.g., depressive symptoms, quality of life) over three years.
Publications
- Röhr S, Reppermund S, Matison A, Samtani S, Sachdev PS. Making time for brain health: recognising temporal inequity in dementia risk reduction. The Lancet Healthy Longevity. 2025 Oct 13. DOI/10.1016/j.lanhl.2025.100768
- Matison AP, Samtani S, Brodaty H, Sachdev PS, Reppermund S. How well do social frailty indices predict incident dementia in older adults? J Gerontol B Psychol Sci Soc Sci. 2025 Sep 25;80(10):gbaf148. DOI/10.1093/geronb/gbaf148
- Cerin E, Matison AP, Molina MA, Schroers RD, Li W, Knibbs LD, Catts VS, Wu YT, Soloveva MV, Anstey KJ, Mavoa S, Poudel G, Jalaludin B, Kochan NA, Brodaty H, Sachdev PS. Neighborhood environments and transition to cognitive states: Sydney Memory and Ageing Study. Alzheimers Dement. 2025 Aug;21(8):e70569. DOI/10.1002/alz.70569
- Samtani S, Mahalingam G, Lam BC, Lipnicki DM, Numbers K, Lima-Costa MF, Blay SL, Costa EC, Xiao S, Riedel-Heller S, Röhr S, Pabst A, Scarmeas N, Yannakoulia M, Kosmidis, M Krishna, M Kumaran, Shahar S, Ng TP, Ho R, Kim KW, Skoog I, Najar J, Sterner T, Ganguli M, Chang C-CH, Hughes TF, Sachdev PS, Brodaty H, for the Cohort Studies of Memory in an International Consortium (COSMIC). Emotional and instrumental social support and older adults’ depressive symptoms: collaborative individual participant data meta-analysis of 11 population-based studies of aging. American Journal of Epidemiology. 2025 Oct;194(10):3041-9. DOI/10.1093/aje/kwaf137
- Rodriguez, F. S., Hofbauer, L. M., Reppermund, S., Samtani, S., & Röhr, S. (2025). Updating risk and protective factors for dementia in older adults. Nature Reviews Psychology, 4(5), 322–335. DOI/10.1038/s44159-025-00438-w