From Ouroboros: "Do DNA double-strand breaks (DSBs) have anything to do with aging? We have some reason to believe that they do. ... Paul Hasty has written two recent reviews, critically evaluating the role of DNA DSBs in the aging process. In the first (written with colleagues Han Li and James Mitchell), the authors argue from genetic evidence that DSB repair pathways are intimately connected with aging, but that the relationship is distinct from the well-documented connection between aging and repair of UV-type damage. ... In the second review, Hasty [argues] that non-homologous end-joining (NHEJ), a major pathway of DSB repair, evolved primarily as a means to slow aging - rather than to prevent cancer, as is likely the case for other DNA repair pathways." You'll find a two part discussion on the subject back a way in the Fight Aging! archives. The role of DNA damage in aging is more hotly debated and uncertain than, say, the role of mitochondrial damage or stem cell decline in aging.