Having overtaken heart disease as the leading cause of death in Australia, dementia is often preceded by mild cognitive impairment (MCI). Australian research is exploring whether we can slow cognitive decline but, in the meantime, GPs play a key role in managing risk factors, says Professor Kaarin Anstey, Director of the UNSW Ageing Futures Institute and Conjoint Senior Principal Research Scientist at NeuRA, who is leading the study.

Dementia prevalence set to skyrocket

Approximately 425,000 Australians were living with dementia in 2024 according to Australian Institute of Health and Welfare estimates, with prevalence predicted to nearly double by 2054 unless there’s a medical breakthrough.

Subjective cognitive decline (SCD), MCI and dementia exist on a continuum, with one often—although not always—leading to the other, Professor Anstey explains.

About one in five Australians aged 70 or older has MCI, of which one in three will develop dementia within three to five years. A further 11% of Australians aged 65 and older have SCD, and about 14% of them will convert to dementia within four years, she says.

“So these are high prevalence conditions in our older population. There are some reversible causes of those conditions, and some people just stay in MCI for the rest of their lives. So it’s not inevitable, but it is a window of opportunity for intervention.”

She explains prevalence will continue to rise due to population ageing, greater awareness, and the impact of chronic diseases like obesity, diabetes, and hypertension.

“Those chronic conditions are much better managed now, so we’re seeing a reduction in deaths from heart disease, for example, but those people are now still alive and they’re more at risk of dementia.”

Changing the dementia trajectory

Approximately 45% of dementia cases could be prevented by addressing modifiable risk factors, research shows.

“Observational studies show people who have a healthier lifestyle—who are physically active, eat usually a Mediterranean or MIND-type diet and stay cognitively engaged—those people have slower cognitive decline and reduced risk of dementia,” Professor Anstey says, noting that recent studies published in Neurology and JAMA have shown that people with higher levels of physical activity were less likely to develop Alzheimer’s blood biomarkers.

Some international clinical trials have also shown that “intervening with lifestyle can slow the rate of cognitive decline,” she adds, although we still need more evidence for these interventions long term.

What can GPs do in the meantime?

GPs play an essential role in mitigating risk of cognitive decline, Professor Anstey says, but many do not feel adequately equipped, an October Healthed survey found.

While three-quarters of over 1,000 GPs had assessed at least one patient for memory or cognitive issues in the previous two weeks, 41% said they were slightly or not at all confident in supporting someone with a new MCI diagnosis. Half had referred someone for further assessment to determine if they had cognitive impairment.

Evaluating and managing risk factors as early as possible is key, Professor Anstey says.

“So ensuring that their vascular risk factors are managed—their hypertension, high cholesterol—and then looking at lifestyle—physical activity and diet, cognitive stimulation, but also mental health. Depression is very important, and we do see an uptick of depressive symptoms in people with MCI. So I would be looking at all those modifiable risk factors and making sure they’re all managed optimally.”

To assess risk factors, she recommends the CogDrisk tool.

“That would give you a good sense of whether the person is not doing enough physical activity, or is lonely, or has a high rate of high depressive symptoms,” she says.

Depending on the findings, patients may benefit from referral to a dietitian, exercise physiologist, or mental health professional.

Assessing cognition

The Mini-Mental State Examination and Montreal Cognitive Assessment are leading tools, but they are not perfect, Professor Anstey stresses.

Importantly, patients with early-stage cognitive decline, particularly younger adults or those who are high functioning, probably won’t reach cutoffs on objective tests, but a drop in their scores is telling, she says.

“Say they previously got 30 out of 30 on Mini-Mental, they might go down to 28 or 27—which is still well above the threshold for probable dementia. But they’ve started to show that decline and that is significant if it is consistent over time.”

These tests can be particularly inaccurate in highly educated patients, she adds.

“Someone who is very highly educated might still be scoring above the cutoff for a while whilst they’re declining, so they’re not going to show up as impaired,” she says.

It’s crucial to consider the personal experience of patients and their families, she points outs.

“If they consistently feel that there’s something wrong over a long period of time, we know now that shouldn’t be ignored. That’s where we have this subjective cognitive decline and it should be taken seriously, even if it’s not showing up on an objective test.”

If you’re unsure, she recommends retesting in six to 12 months.

“If it is the beginning of clinically significant cognitive decline, it won’t go away, whereas there are other cognitive complaints that are transitory. So people that have sleep problems, people on psychotropics or anticholinergics, people who are depressed and anxious, can have a lot of problems with their cognition.”

“And once they’re treated or taken off those medications, their cognitive complaints resolve, whereas someone who’s in this preclinical stage that won’t resolve. You could treat all those other things, and it will still be there.”

Australian trial aiming to stave off cognitive decline

GPs can also encourage patients to take part in research, like the CogCoach-Health trial Professor Anstey is leading.

Conducted completely online, this study is exploring whether lifestyle interventions can reduce risk factors and slow cognitive decline in people with MCI and SCD.

Participants in the intervention group receive an e-learning program with activities, videos and educational material, plus sessions with an exercise physiologist, dietician, and psychologist who prescribe personalised exercise, dietary and cognitive training strategies. They also get 12-months of access to an evidence-based cognitive training package and the Standing Tall app—which supports ongoing physical activity.
Participants randomised to the control group get weekly emails that mirror the e-learning course, and full access to it at the end of the study.

Cognitive function and medical/behavioural risk factors are assessed at entry and 3, 6 and 12 months thereafter.

“What’s really novel about this trial is that it’s done completely online, which means we can reach into those regional and rural areas as well as anyone living in a city,” Professor Anstey says. “So it’s very accessible, and that’s been a bit of a barrier to participation in these sorts of studies before.”

“Participants get a lot of support from the research team which includes clinicians as well as research staff.”

If successful, the trial will hopefully lead to development of a package GPs can offer to patients with cognitive complaints or MCI.

They are seeking more participants, who need to be aged 65 years or older with changes in memory or cognition or an MCI diagnosis. The research team will conduct comprehensive eligibility screening.

GPs can refer patients via the CogCoach-Health website. To find out more or get brochures for your clinic, email cogcoach.health@unsw.edu.au or call (02) 9348 3111.