University of Sydney researchers and clinicians are rewriting the playbook on healthy ageing. By uncovering how sleep quality and oral health across our lifespan shape cognitive resilience in later life, their work is prompting a renewed focus on midlife – and redefining what good aged care looks like.
The links between sleep and cognitive health
Understanding how everyday choices can shape cognitive health across our lifespan and influence our dementia risk is a theme of emerging sleep science. Professor Sharon Naismith AM, who heads the Healthy Brain Ageing Program at the University’s Brain and Mind Centre, explains how sleep research is playing an increasingly important role in our understanding of cognitive decline and dementia.
“We know that about 45 percent of dementias are due to things that are modifiable – such as depression, cardiovascular disease, alcohol consumption, hearing loss, and how much education you’ve had,” she says. “Evidence also links restorative sleep to alertness and laying down new memories, while poor sleep duration is linked to a higher risk of dementia – and we know that pathology leading to dementia begins to build up from midlife.”
Sharon’s pioneering research explores whether sleep disturbances play a causative role in dementia, or whether they’re a by-product of age-related degeneration of the circuits that support sleep.
“We’re looking at the mechanisms by which different forms of sleep disturbance may trigger or exacerbate the build-up of beta-amyloid [a protein involved in cognitive decline] and other pathologies in the brain that lead to dementia generally and Alzheimer’s disease specifically,” she explains. We believe that sleep flushes proteins like this from our brains, and that process is diminished in ageing, as well as in some medical conditions and sleep disorders.
“With sleep apnoea, for example, there is a dip in blood oxygen levels and sleep becomes quite fragmented, which can impact the deep stages of sleep. In turn, this can disrupt the important restorative role of sleep, the consolidation of memories, and can potentially impact the drainage of waste products from the brain. So many people in our memory clinic setting have undiagnosed sleep apnoea and other forms of sleep disturbance.”
Sharon is currently scaling this important work using advanced technologies to test participants and develop interventions that improve sleep and memory. In addition to other techniques, her research uses affordable monitoring that can be done at home, such as with a simple oximeter to study sleep apnoea in older adults.
“Given the high prevalence of these disorders and that some effective therapies already exist, we need to develop more cost-effective and scalable ways to screen people presenting to memory clinics with cognitive concerns,” she says. “With effective screening and treatment, we can potentially slow dementia and improve quality of life for older people.”
The team at the Brain and Mind Centre, in partnership with the Australian Dementia Network and the Department of Health, have also recently launched a virtual memory clinic model for people in regional and rural Australia, to address inequities in access to specialist care.
Sharon emphasises that good sleep hygiene needs to be prioritised throughout the ageing process, not just in our later years. “Be mindful of healthy brain ageing from midlife – which is typically your 40s and 50s,” she advises. “From that time, you really have to keep your brain and body active – sleep will naturally follow.” She offers some more specific tips below.
How to establish good sleep habits
- Wake up at the same time every day, including weekends, to support your natural circadian rhythm.
- Keep your body and brain active during the day, to promote sleep quality at night. Keep daytime naps short (under 20 minutes) and before 2 pm.
- Avoid caffeine from late afternoon onwards.
- Avoid using your smartphone in the evening, as bright light keeps your brain alert.
- Keep your bedroom cool, as lower temperatures support better‑quality sleep.
- If you snore, gasp for air during sleep, or feel excessively sleepy during the day, speak to your doctor.
Oral health and dementia risk
Good oral health is also critical to our quality of life as we age, aff ecting our ability to comfortably eat, talk and socialise. But despite its close links to overall wellbeing, it remains one of the most overlooked areas of health care, according to Associate Professor Ankur Singh, the University of Sydney’s Chair of Lifespan Oral Health.
“One in ten Australian adults does not have the minimum number of teeth needed for daily functions,” explains Ankur, whose work is supported by the generosity of Sue and Alex Abrahams through The Rosebrook Foundation. (Source: Australian Institute of Health and Welfare, National Study of Adult Oral Health 2017–18.) And this figure is significantly higher among those who have low education or who are members of Aboriginal and/or Torres Strait Islander communities.
Thousands of Australians currently have poor oral health and struggle to access dental care, something Ankur describes as “a social and economic issue that hasn’t yet reached the policy table”. Within the context of ageing, he adds, “We want people to be able to live independently and lead a life with dignity as they age. But if you’re embarrassed about your teeth, or can’t engage with people due to impediments caused by poor oral health, how is healthy ageing possible?”
Perhaps even more concerning is that oral health issues are also associated with increased cognitive decline. “There is a bi-directional relationship between dementia and poor oral health,” Ankur explains. “When you have poor oral health, it can impact your capacity to go out, both from a speech and nutrition perspective,” and poor social engagement is known to be associated with increased dementia risk. Conversely, those with dementia tend to have worse oral health outcomes, often due to isolation and poor social participation.
Ankur believes that change is needed within the oral health space throughout the ageing process – not purely in early life and then again in old age. “We look at people early in life, and towards the end, but what about the main Australian population in the middle of their lives?” he says. “If you leave people to themselves throughout large chunks of their adulthood, when they’re also prioritising children and ageing parents and having financial hardships, that’s the bit that really worries me. If your stress levels are high, you usually feel less control in your life, and that can impact everything from your time structure to trying to improve your nutrition – and that’s what’s currently lacking in the oral health literature.” Ankur offers some simple practices we can all adopt to support our oral health and therefore our overall wellbeing.
How to protect your oral health
- Cut back on inflammatory triggers. Maintaining a healthy diet, cutting down on sugar, and avoiding alcohol and tobacco can all help to lower systemic inflammation.
- Manage stress early. We all know that regular brushing and dental check‑ups matter. But high stress often erodes our oral health by making it tougher to prioritise these healthy routines along with our nutrition, hygiene and self‑care, all of which can undermine immunity and therefore oral health.
- Focus on realistic changes. Small, manageable habits are more sustainable than overly ambitious goals – especially when we feel short of time or control.
Redefining aged care
As research continues to reveal how modifiable lifestyle factors shape ageing, attention is also turning to how care systems respond – particularly for people already living with cognitive decline.
Professor Yun-Hee Jeon, the University of Sydney’s Susan and Isaac Wakil Professor of Healthy Ageing, is exploring innovative ways of redefining what it means to age well, with the ultimate aim of improving aged care.
“I’m trying to make sure we off er the care people deserve,” explains Yun-Hee, who has developed evidence-based rehabilitation and reablement tools for those living with dementia, as well as delivering workforce training to strengthen preventive health care and improve older people’s wellbeing.
Along with collaborators at the US-based Johns Hopkins University, Yun-Hee has developed reablement programs to support people with dementia, who are often excluded from more general rehabilitation programs.
“They may get rehab if they actually have a fall or have problems with their knees,” she explains, “but the major gap is often to do with practitioners who aren’t necessarily trained to deliver care that focuses on improving the independence of people living with dementia and engaging them in a way that is meaningful to them. There’s sometimes a misconception that nothing can be done.”
Yun-Hee’s program is designed to bring nurses and other multidisciplinary team members together to provide a comprehensive rehabilitation offering appropriate for people with dementia. “There are many interventions that people with dementia can benefit from, but too often they’re never referred to them,” she says. “Support from speech pathologists, occupational therapists and physiotherapists can make a real difference. I think we often just hasten the process, rather than trying to support someone to have that sense of independence and purpose.”
Reablement supports people living with dementia to maintain or rebuild skills, from preparing meals and getting around to communicating and engaging in activities. Importantly, it operates on the principle of collaboration rather than simply providing care – doing things with people rather than doing things for them. “I’ve learned so much from people with lived experience,” Yun-Hee reflects, acknowledging in particular John Quinn, who lives with younger-onset dementia and actively participates in dementia research.
Yun-Hee’s commitment to improving dementia care is further reflected in an initiative called StepUp for Research (Dementia and Ageing), which links participants both with and without dementia to researchers studying prevention, care and treatment, helping to accelerate research outcomes.
Ultimately, Yun-Hee believes there is still much to be done to raise awareness of the inequities that exist in this space. “Health is not just about physical health,” she says. “Our sense of purpose and independence is shaped by the interplay of physical, mental and social health. If you can do something on your own and feel independent, it’s just so important.”
How to care for yourself or a family member with dementia
- Remember that a dementia diagnosis does not automatically mean a life of dependence. Having confidence that independence is still possible – both for the person with dementia and for their family – can make a real difference..
- Reach out as early as possible to support services that promote independence.
- Set goals based on what the person actually values, and build practical strategies to achieve them. This approach can make a significant difference to the person’s quality of life.
- Create opportunities for meaningful activities, whether big or small. This helps to nurture a sense of purpose.
- Remember that we are all are interdependent. Rehabilitation and reablement are about collaborating and maintaining independence, in whatever form it may take.
Reframing dementia in Chinese-speaking communities
When University of Sydney PhD candidate Zihan He began exploring how members of Chinese-speaking communities talk about dementia, he realised that the word itself was part of the problem.
The traditional Chinese term for dementia translates as ‘dummy disease’ or ‘idiocy’, a label obviously steeped in shame and stigma. Another term used, ‘brain degeneration syndrome’, is medically inaccurate and refers more properly to a wider range of health conditions.
“For many Chinese families, the old term was so insulting they avoided seeking help,” explains Zihan, an international student from China who has since been awarded his PhD.
Zihan consulted dementia experts across mainland China, Hong Kong, Taiwan, Malaysia and Singapore, exploring how terminology aff ects stigma and understanding. His research, supervised by Professor Christine Ji and Professor Lee-Fay Low, led to a new, culturally sensitive term that translates as ‘cognitive impairment syndrome’.
This preferred term, first used in Hong Kong, has now been endorsed by Dementia Australia and is expected to be adopted internationally. It also underpins the University-led Facing Dementia Together awareness campaign, which targets Chinese, Vietnamese and Arabic-speaking communities in Southwestern Sydney, supporting families to start conversations and seek GP assessments.
Zihan’s Culturally Appropriate and Linguistically Understandable (CALU) translation model has been embraced by Chinese Australians participating in community education sessions.
For Zihan, this research was also personal, inspired by a family member in China who was aff ected by dementia but never sought help due to stigma. “I want to help people feel seen, respected and supported – no matter the language they speak,” he says. “By changing the language, we can change attitudes and lives.”