Longitudinal studies don’t just capture health at a moment in time – they reveal how it changes, accumulates and diverges across decades. They allow researchers to link behaviour, environment, genes, policy and lived experience to long-term outcomes, helping governments and health systems plan for the future with evidence rather than assumption. Around the world, this approach has shaped prevention strategies, informed economic policy, guided clinical practice and reshaped our understanding of human health across the life course.
The global impact is undeniable
In the United Kingdom, UK Biobank – tracking more than 500,000 participants – has uncovered genetic markers for dementia, heart disease and cancer; identified how lifestyle factors such as sleep, diet and activity influence disease risk; and enabled risk prediction tools now informing clinical decision-making and personalised prevention research internationally.
Across the Tasman, New Zealand’s Dunedin Study has followed a birth cohort from infancy into mid-life, demonstrating that early adversity predicts later-life disease, that childhood self-control correlates strongly with long-term financial stability and wellbeing, and that early intervention delivers life-long payoff. Its findings have influenced education policy, mental health prevention strategies and early-life support programs globally.
These studies have one thing in common: they didn’t just generate knowledge – they changed systems.
The Sax Institute’s own 45 and Up Study is one of the largest ongoing long-term studies in the Southern Hemisphere, following more than 250,000 people since 2005. It has provided critical evidence for healthy ageing, chronic disease prevention and cancer screening policy; supported trials such as Maintain Your Brain; advanced cardiovascular and diabetes research; and deepened understanding of how social connection influences long-term health outcomes. The study continues to evolve, offering an unmatched platform for research and policy translation in later life.
Now, Australia is preparing for the next leap – one that builds on this legacy and expands the lens into younger adulthood.
The future of longitudinal studies in Australia
The 18 and Up Study, powered by the infrastructure and experience of 45 and Up, will broaden reach across younger and mid-life adults, increase cohort diversity, and integrate emerging data collection approaches including digital tools and linked administrative datasets. This is a once-in-a-generation opportunity to create one of the most comprehensive population health research resources in the world – one that can track how external factors like climate, housing pressure, digital environments, work patterns, stress, policy decisions and social change shape mental health across adulthood.
Together, 18 and Up and 45 and Up will allow researchers to study transitions across life stages, compare generational cohorts, and rapidly respond to emerging health challenges. The potential spans real-time population monitoring, digital-twin modelling to test prevention strategies before implementation, earlier identification of risk, and evidence-driven policy decisions that improve lives decades into the future.
This is the evolution of Australian longitudinal research – deeper, broader and more future-focused. With 45 and Up as a strong foundation and 18 and Up expanding the next generation of evidence, Australia is well-positioned to shape global longitudinal research for decades to come.
As planning continues, the focus now turns to 2026 – when recruitment and surveying for 18 and Up will begin. We welcome input, ideas and collaboration from across the policy and research sectors as the study takes shape. To learn more or to be part of the conversation, please contact Matthew Gorringe, Head, Data and Research Services.
