How Aging Leads to Disease: New Two-Stage Model Explains Age-Related Illness

BUFFALO, NY — January 20, 2026 — A new #review was #published in Volume 17, Issue 12 of Aging-US on December 30, 2025, titled “Aging as a multifactorial disorder with two stages.” “This article is a contribution to the special issue of Aging celebrating the life and work of Misha Blagosklonny (more formally, Mikhail Vladimirovich Blagosklonny), who died in October 2024.” In this review, David Gems and Alexander Carver from University College London, together with Yuan Zhao from Queen Mary University of London, present a new theoretical model to explain how aging leads to the development of chronic diseases. Drawing on evolutionary theory and biological research, the authors propose that aging is driven by a combination of early-life damage and harmful genetic activity in later life. This framework helps explain why diseases such as cancer, arthritis, and infections often appear in old age and offers insight into how they might be prevented. Aging is the biggest risk factor for most chronic diseases, but the biological reasons for this association are still debated. The authors address this by introducing a two-stage model. In the first stage, individuals experience disruptions early in life, such as infections, injuries, or genetic mutations. Although the body can often contain or repair this damage, it does not fully eliminate it. In the second stage, which begins in later life, normal genetic processes begin to act in ways that are no longer beneficial. These late-life changes weaken the body’s ability to contain earlier damage, allowing it to develop into disease. The review emphasizes that aging is a multifactorial process, shaped by many interacting causes rather than a single underlying mechanism. The model suggests that early-life disruptions and later-life genetic activity work together to drive age-related diseases. For example, dormant viruses can re-emerge as infections like shingles due to weakened immunity in older adults. Similarly, injuries to joints in youth can lead to osteoarthritis as tissues change with age. Inherited mutations may also remain silent for decades before contributing to conditions such as cancer or fibrosis later in life. This two-stage model builds on long-standing ideas from evolutionary biology, particularly the theory that aging occurs because natural selection has less influence in later life. The authors also draw on studies in the roundworm Caenorhabditis elegans, where early mechanical damage can lead to fatal infections in old age, suggesting similar patterns may occur in humans. Overall, this review presents a new framework for understanding how different causes of aging interact over time. By identifying two key stages, early-life damage and late-life genetic activity, it highlights potential strategies for promoting healthier aging through prevention and targeted intervention. DOI - https://doi.org/10.18632/aging.206339 Corresponding author - David Gems - david.gems@ucl.ac.uk Abstract video - https://www.youtube.com/watch?v=d4TSI4Ot3yM Sign up for free Altmetric alerts about this article - https://aging.altmetric.com/details/email_updates?id=10.18632%2Faging.206339 Subscribe for free publication alerts from Aging - https://www.aging-us.com/subscribe-to-toc-alerts Keywords - aging, C. elegans, disease, hyperfunction, multifactorial model To learn more about the journal, please visit https://www.Aging-US.com​​ and connect with us on social media at: Bluesky - https://bsky.app/profile/aging-us.bsky.social ResearchGate - https://www.researchgate.net/journal/Aging-1945-4589 X - https://twitter.com/AgingJrnl Facebook - https://www.facebook.com/AgingUS/ Instagram - https://www.instagram.com/agingjrnl/ LinkedIn - https://www.linkedin.com/company/aging/ Reddit - https://www.reddit.com/user/AgingUS/ Pinterest - https://www.pinterest.com/AgingUS/ YouTube - https://www.youtube.com/@Aging-US Spotify - https://open.spotify.com/show/1X4HQQgegjReaf6Mozn6Mc MEDIA@IMPACTJOURNALS.COM