What Is a Biomarker of Ageing?

Definition

A biomarker of ageing is a measurable biological feature that reflects the functional state of an organism and predicts future health or mortality better than chronological age alone. It can be molecular, physiological, or functional, but it must track meaningful changes in biological integrity and age-related risk across populations. [1] [2] [7]

Core Criteria

Researchers look for biomarkers that change with age, relate to health outcomes, and respond to interventions. An ideal marker is reliable, practical to measure, and relevant across populations, and should capture biological ageing beyond chronological time. Consensus criteria emphasize validity, reproducibility, sensitivity to intervention, and predictive utility for functional decline or mortality. [3] [4] [5]

Domains of Measurement

Ageing affects multiple levels of biology. Biomarkers may capture molecular processes (like DNA methylation), organ function (like lung capacity), or whole-body performance (like walking speed). Multidimensional panels are therefore favored over single markers, because no single domain captures the full picture of ageing biology. [2] [4] [6]

Research and Clinical Use

Most biomarkers are research tools used to compare populations, study mechanisms, and test interventions. Clinical adoption is more limited because the standards for diagnosis and treatment are higher than those for exploratory research, and many candidates lack sufficient validation for routine clinical decision-making. [2] [7]

Summary

A biomarker of ageing is a measurable indicator of biological decline that predicts health outcomes beyond age in years. The strongest candidates are reliable, mechanistically relevant, and sensitive to interventions, but no single marker is sufficient on its own. [2] [4] [7]

References

1. Baker, G. T., & Sprott, R. L. (1988). Biomarkers of aging. Experimental Gerontology, 23(4-5), 223-239. https://pubmed.ncbi.nlm.nih.gov/3058488/
2. Biomarkers of Aging Consortium, Moqri, M., et al. (2023). Biomarkers of aging for the identification and evaluation of longevity interventions. Cell, 186(18), 3758-3775. https://pmc.ncbi.nlm.nih.gov/articles/PMC11088934/
3. Xia, G., et al. (2024). Biomarkers of Aging and Relevant Evaluation Techniques. Frontiers in Medicine. https://pmc.ncbi.nlm.nih.gov/articles/PMC11081160/
4. Horvath, S., & Raj, K. (2018). DNA methylation-based biomarkers and the epigenetic clock theory of ageing. Nature Reviews Genetics, 19(6), 371-384. https://onlinelibrary.wiley.com/doi/abs/10.1002/mef2.50
5. Expert consensus statement on biomarkers of ageing for use in intervention studies. Journal of Gerontology: Biological Sciences (2025). https://academic.oup.com/biomedgerontology/article/80/5/glae297/7930267
6. Zhang, C., Zhu, P., et al. (2023). Biomarkers of aging. Signal Transduction and Targeted Therapy, 8(1), 144. https://pmc.ncbi.nlm.nih.gov/articles/PMC10115486/
7. Cohen, A. A. (2025). Biomarkers of aging: functional aspects still trump molecular detail. Journal of Gerontology: Biological Sciences. https://pmc.ncbi.nlm.nih.gov/articles/PMC11876623/