Digital biomarkers of ageing for monitoring physiological systems in community-dwelling adults

Digital health technologies are transforming health care and personal health management by providing quantifiable data on physiological, behavioural, and environmental health parameters using digital biomarkers. This narrative review classified, characterised, and evaluated digital biomarkers of ageing across ten physiological systems to explore the applications of these biomarkers in research and clinical practice. The systematic search identified minimally invasive or non-invasively measured digital biomarkers suitable for longitudinal studies and practical use by community-dwelling adults. The digital biomarkers were classified according to their physiological system, characterised by their capture methods, and evaluated based on the following criteria: validity (age-associated, function-associated, and mortality-associated), generalisability, responsiveness to interventions, associations with clinical outcomes, and cost-effectiveness in large-scale settings. Digital biomarkers of ageing were found across eight physiological systems. Registered clinical trials that used these digital biomarkers as outcomes were also identified. Continued research and technological advancements are crucial for maximising the potential of digital biomarkers in promoting healthy ageing and longevity.