A new review proposes that aging-related diseases develop through two connected phases across a person’s lifetime. Published in Aging-US, the paper from scientists at University College London and Queen Mary University of London combines evolutionary biology with biomedical findings to explain links between early damage and later illnesses such as cancer and arthritis.
The first phase involves disruptions early in life, including infections, injuries or genetic mutations. Although the body often repairs or contains much of this harm, some effects may persist undetected.
In the second phase, normal genetic activity shifts in later years in ways that reduce the body’s capacity to manage earlier damage. This allows previously contained issues to progress into disease.
The model accounts for conditions like shingles, where dormant viruses reactivate as immunity declines, and osteoarthritis, where youthful injuries become problematic as tissues lose resilience. Inherited mutations may also remain inactive for decades before raising risks for cancer or fibrosis.
Drawing on evolutionary theories, the authors note that natural selection weakens with age, permitting harmful processes to appear. Experiments with roundworms showed early damage leading to fatal infections in old age, suggesting parallel patterns in humans.
The framework could inform strategies to prevent damage early in life or address harmful changes later, potentially lowering chronic disease rates in older adults.
