Intrinsic capacity a strong marker of healthy ageing

Researchers from the University of Adelaide have been exploring the genomic links within Intrinsic Capacity in the hopes it will pave the way for targeted health interventions and better maintenance of functional abilities as people age.

The concept of IC was introduced by the World Health Organisation in 2015 and refers to the composite of an individual’s physical and mental abilities across the five domains of cognition, vitality, sensory function and psychological health.

Senior author and Associate Professor Azmeraw Amare said the UoA study is the first of its kind to explore the genetic architecture of IC – analysing genetic data from more than 57,000 people who participated in the UK Biobank and Canadian Longitudinal Study on Ageing.

It found genetic factors account for about 20 to 25 per cent of the variability in IC, with environmental and lifestyle factors accounting for the rest.

“These findings provide a foundational understanding of the biological mechanisms that support healthy ageing,” Dr Amare explained.

First author and PhD candidate Melkamu Beyene said the identified genes are involved in critical biological processes relevant to healthy ageing processes, including:

• metabolism
• immune function
• neurodegeneration
• cellular ageing.

“By identifying the genetic factors that influence IC, we can begin to develop targeted interventions to help people maintain their functional abilities as they age.”

“These genes are highly expressed in the brain, heart, muscle, and body tissue,” Mr Beyene said.

Since IC was introduced, it has been considered a powerful predictor of many outcomes, including mortality, care dependence, and a range of chronic diseases, even after accounting for personal characteristics and multimorbidity.

“Unlike disease and disability, which are relatively late and separate measures of poor health in older adults, IC provides a holistic and continuous framing of health that mirrors recent work on the complex and dynamic biological changes that drive ageing,” Mr Beyene said.

Head of the Adelaide Geriatrics Training and Research with Aged Care Centre Professor Renuka Visvanathan added that the research “opens the door” to more personalised approaches to promoting healthy ageing.

“These insights could help clinicians better predict and support healthy ageing trajectories,” she said.

The results were published in the Journal of Gerontology: Biological Sciences and also found strong correlations between IC and traits like lung function, grip strength and cognitive performance.

IC a better predictor of dementia

Researchers from UNSW Sydney’s Centre for Healthy Brain Ageing and School of Risk and Actuarial Studies have also been looking at IC, finding it serves as a better predictor of dementia and mortality than traditional frailty measures.

The study, published in the International Journal of Geriatric Psychiatry, was the first to validate the five-domain structure of IC in an older Australian cohort, using data from 400 older Australians aged between 70 to 90 who participated in the Sydney Memory and Ageing Study.

The study then calculated participants’ IC scores using the five IC domains and compared them with the Frailty Phenotype and Frailty Index – which look at accumulated health deficits and physical decline to predict dementia, disability and mortality.

“Our findings show that IC not only captures the core elements of healthy ageing but also provides unique predictive value for dementia and mortality over and above deficit-focused frailty measures,” said lead author and CHeBA senior lecturer Dr Katya Numbers.

The study found individuals with higher IC scores had 43 per cent less risk of developing dementia and 35 per cent less risk of mortality after 10 years of follow-up, and after controlling for age, sex and education.

The researchers say the findings have significant implications for healthy ageing and strengthen the case for IC as a core marker of healthy ageing.

Senior author and CHeBA co-director Professor Henry Brodaty also noted that it offers a shift from focusing on deficits to capacity instead.

“Rather than seeing ageing as an inevitable decline, IC provides a more holistic and empowering way to monitor health, intervene early, and support older people to maintain independence,” he explained.

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