Professor David Llewellyn

Professor David Llewellyn is a scientist and innovator working at the intersection of dementia research, public health and artificial intelligence. He is Professor of Clinical Epidemiology and Digital Health at the University of Exeter Medical School, where he leads an interdisciplinary research group and has served as Director of Research and Impact. His work spans the full arc from discovery to real-world impact: understanding what drives dementia risk, detecting disease earlier, strengthening the clinical trials that test new treatments, and developing the digital tools, AI and medical devices that could transform how brain health is predicted, diagnosed and cared for.

He undertook advanced training in neuroepidemiology and data science at the University of Cambridge before joining Exeter in 2009, and was promoted to a full professorship in 2020. From 2018 to 2024 he held a Fellowship at the Alan Turing Institute, the UK's national institute for data science and artificial intelligence, where he co-founded the Turing Interest Group in Precision Dementia Medicine. He has chaired the International Society to Advance Alzheimer's Research and Treatment (ISTAART) interest area on AI for precision dementia medicine.

He works across disciplines and sectors, bringing together clinicians, data scientists, engineers, industry, charities and policymakers to turn research into impact. He directs the DEMON Network, a global initiative of more than 1,700 members harnessing data science and AI to transform dementia research and healthcare, and collaborates with partners including the UK Dementia Research Institute and leading technology companies.

His research has shaped international scientific and policy debate, with 135 peer-reviewed papers — including in JAMA, the BMJ, Nature Genetics, JAMA Neurology, JAMA Psychiatry, Lancet journals, and Alzheimer's & Dementia — cited over 20,000 times. Several are ranked among the 100 most high-profile scientific publications worldwide of their age. His landmark studies include the finding that a healthy lifestyle can help offset genetic risk of dementia (published in JAMA), influential work on the Mediterranean diet and brain health, and machine-learning models that predict who will develop dementia and those likely to be misdiagnosed.

A growing focus of his work is enhancing clinical trials through AI and digital medical devices — identifying and recruiting the right participants, stratifying who is most at risk or most likely to benefit, and improving how treatment effects are measured. This builds on his research using machine learning to optimise trial design and recruitment, and extends to the rigorous validation of AI-based medical devices for clinical use, including distributed validation of AI for neuroimaging in neurodegeneration and his role in a national NIHR HealthTech Research Centre.

This work feeds directly into innovation. He has helped create and validate digital health technologies intended for clinical use, including the award-winning DECODE dementia-identification software, trialled with NHS clinicians, and the ReaCTIVE app for interactive cognitive monitoring, now in clinical validation and commercialisation. His current work also applies custom large language models to precision dementia prevention.

He has secured more than £20 million in research funding, including from the Medical Research Council, the National Institute for Health and Care Research, Alzheimer's Research UK, Alzheimer's Society, the Engineering and Physical Sciences Research Council and the U.S. National Institute on Aging. He contributes to international dementia-prevention guidelines and sits on Alzheimer's Society's Grant Review Board and Alzheimer's Research UK's Clinical Policy Advisory Panel. His findings are reported widely in the international media, including the BBC, The New York Times, The Times, Time magazine and CNN. His recognition includes the Alzheimer's Association New Investigator Award — the first ever made to a UK-based researcher.

Alongside his academic work, David is a scientific advisor and keynote speaker on dementia, brain health, digital health, AI and clinical trials, working with organisations internationally.

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