A University of Tennessee Health Sciences researcher has published findings that could reshape how medicine approaches aging, longevity and late-life health, including the prospect of personalized interventions that keep people healthier longer.
Rob Williams, PhD, professor and chair of the Department of Genetics, Genomics, and Informatics in the College of Medicine, is the lead author on a new study published in Nature titled “Dynamics of genetic and somatic trade-offs in ageing and mortality.” The research identifies specific genetic regions that influence a person’s risk of death at particular stages of life, a significant departure from how longevity research has traditionally been conducted.
For more than a century, scientists studying the genetics of lifespan have relied on a single measure, how long a person lived. Dr. Williams and his team took a different approach, analyzing mortality risk in specific age windows — from 50 to 60, 60 to 70 and 70 to 80 — rather than treating lifespan as a single endpoint.
That shift revealed something that a single-number approach had obscured: the genes influencing your risk of dying at 60 are largely different from those influencing your risk at 75. Aging, the research shows, is not governed by one genetic program but by a series of them, each active at different life stages.
The team identified 29 genetic regions, which they call VITA loci, that modify mortality risk at specific ages. Each represents a potential target for future interventions aimed at extending healthy life.
One of the study’s most striking findings is the degree to which males and females operate on separate genetic aging programs. The VITA loci associated with mortality risk in males and those associated with females are, to a remarkable extent, entirely distinct.
Dr. Williams, who has spent four decades studying mammalian biology, says the finding surprised even him. He believes the divergence reflects the radically different life histories of males and females across species, including different metabolic demands, different reproductive roles and different biological priorities that evolution has encoded into how each sex ages, despite sharing essentially the same genome.
The discovery has direct implications for medicine. Treatments and interventions for age-related disease have historically been developed and tested without fully accounting for sex as a biological variable. This research provides a genetic basis for why that approach may be inadequate.
The most immediate significance of the findings is that they point toward a future in which aging interventions are tailored to an individual’s genetic profile, sex and stage of life, rather than applied uniformly across populations.
Dr. Williams is clear that the goal is not simply to add years to life, but to add health to years. The research aims at what scientists call “compression of morbidity,” extending the period of healthy, functional life while shortening the period of decline at the end. Rather than a prolonged deterioration, the aspiration is a longer health span followed by a faster, less debilitating decline.
“We want to find interventions that will keep you healthy longer,” Dr. Williams said. “And then when you fall off the cliff, which we all are going to fall off the cliff, let’s hope you fall off quickly instead of taking 20 years to fall off.”
The study also carries a practical near-term message about body weight in older adults. The data show that while larger body size is associated with worse outcomes in younger animals, the relationship reverses in old age, where maintaining body mass becomes protective. The research confirms that rapid, unintentional weight loss in elderly individuals is a significant biological warning sign, not a health achievement.
The research draws on a dataset made possible by the National Institute on Aging’s Interventions Testing Program, which has tracked mice from birth to death since 2004. Dr. Williams gained access to DNA samples from approximately 25,000 related mice, a family of siblings with known genetics, controlled environments and complete lifespan records.
To date, his team has genotyped roughly 7,200 of those samples, with the current Nature paper representing findings from that portion of the dataset. Analysis of the full 25,000-sample collection is ongoing and expected to yield even more definitive results.
The work has been supported in part by the state of Tennessee through the Center for Integrative Translational Genomics and the UT–Oak Ridge Innovation Institute Governor’s Chair, and involved collaborators across genetics, statistics, computer science and evolutionary biology.
Dr. Williams estimates that within 10 years, the findings in mouse models could yield specific, evidence-based recommendations tailored to an individual animal’s genetic profile, a proof of concept that would bring personalized aging medicine meaningfully closer for humans.
“The next phase is to figure out how to improve healthspan — what drugs, what interventions that are pretty easy, will improve your quality of life and keep you healthy until the very end.”