A team under the direction of Ben Shenhar spent months going through old twin records from Sweden and Denmark, some of which date back more than a century, and running the data through mathematical models intended to distinguish one type of death from another in a research building on the campus of the Weizmann Institute of Science in Israel. Extrinsic mortality is the term used by researchers to describe deaths that are unrelated to aging, such as accidents, infections, and violent crimes. Intrinsic mortality, which is shaped by genes, includes biological deterioration, illness, and the slow breakdown of previously functional systems. It turns out that the difference is crucial. After removing extrinsic deaths from the data, Shenhar’s team discovered something that subtly disproved decades of scientific agreement regarding the extent to which your DNA truly affects your longevity.
The prior estimate ranged from 20 to 25 percent. According to some extensive pedigree studies, inherited factors may account for as little as 6% of the variation in human lifespan. The implication, which was widely acknowledged and reiterated, was that the vast majority of individual differences in longevity can be attributed to behavior, environment, and chance. The basic tenet of public health guidelines was to “eat well, exercise, avoid cigarettes, and wear a seatbelt.” At best, genetics was a minor factor. According to a recent study that was published in Science in January 2026, intrinsic human lifespan is about 50% heritable. It’s not a small change. That is a doubling of the entire prior framework, and it modifies the questions that researchers ought to ask about aging as well as the kinds of interventions that might be worthwhile.
| Study Overview: Lifespan Heritability Research — Weizmann Institute | Details |
|---|---|
| Study Title | Heritability of intrinsic human life span is about 50% when confounding factors are addressed |
| Published In | Science — January 29, 2026; Vol. 391, Issue 6784, pp. 504–510 |
| Lead Researcher | Ben Shenhar — lab of Prof. Uri Alon, Weizmann Institute of Science, Molecular Cell Biology Dept. |
| Previous Lifespan Heritability Estimate | 20–25% (twin studies); some large pedigree studies placed figure as low as 6% |
| New Heritability Estimate | Approximately 50% — at least double all prior estimates; aligns with heritability of other complex human traits |
| Data Sources | Three Scandinavian twin databases — Sweden and Denmark; included twins raised apart for first time in this research type |
| Key Innovation | Mathematical modeling and virtual twin simulations to separate intrinsic (biological aging) deaths from extrinsic (accidents, infections) deaths |
| Dementia Heritability Finding | Up to age 80, dementia risk shows ~70% heritability — higher than cancer or heart disease |
| Centenarian Longevity Gene Probability | Likelihood of inheriting longevity genes: 0.48 in men, 0.33 in women — among centenarians aged 100–109 |
| World Population Aging Projection | Nearly 22% of global population expected to be 60+ years old by 2050 |
| Research Funding | Sagol Institute for Longevity Research; Knell Family Institute for AI; Zuckerman STEM Leadership Program |
Just as important as the discovery itself is the methodological innovation. The fact that the earliest datasets were gathered during times when extrinsic mortality was significantly higher than it is today made it impossible for earlier twin studies, which are the conventional method for distinguishing genetic from environmental influences.
The Scandinavian cohorts that serve as the study’s foundation were born in the late 1800s and early 1900s, a time when infections, accidents, and violence were common causes of death that had nothing to do with their underlying biological aging. The genetic signal was weakened when those deaths were taken into account when calculating heritability. To account for this, Shenhar’s team developed mathematical models and performed virtual twin simulations, thereby removing a layer of noise that had been hiding the genetic influence for many years. The outcome is a much more accurate estimate that, according to the researchers, is consistent with the heritability patterns observed in the majority of other complex human traits.
Particular attention should be paid to one particular finding. The study discovered a heritability of roughly 70% for dementia risk up to age 80, which is significantly higher than that found for heart disease or cancer. It is a striking and somewhat paradoxical asymmetry. Family history has long been considered a standard clinical variable in discussions of genetic risk factors for heart disease. However, it seems that the genetic component of dementia is even more profound, raising serious concerns about how research priorities and therapeutic funding should be distributed among various aging-related disorders. The focus on lifestyle interventions for dementia prevention, such as diet, exercise, and cognitive stimulation, may be somewhat at odds with what biology actually indicates about the locations of the most significant leverage points.
It is important to keep in mind that this research has a longer context. For years, the biology of aging, or biogerontology, has been gathering data regarding particular genes and pathways that affect lifespan in various species. In organisms ranging from yeast to mice to humans, genes related to cellular stress response, insulin signaling, and DNA repair have all been connected to longevity. In comparison to the general population, centenarians—those who live to be 100 years of age or older—tend to exhibit prolonged periods of good health, with lower rates of cancer, cardiovascular disease, dementia, and Alzheimer’s. The likelihood of acquiring the gene variants linked to that type of longevity seems to rise with age; among centenarians in the 100–109 age range, it is approximately 0.48 for men and 0.33 for women. That inheritance signal is not insignificant. It implies that extraordinary longevity tends to cluster in families in ways that are not entirely explained by lifestyle.
Practically speaking, the Weizmann study strengthens the scientific argument for searching more closely for the particular gene variants that determine this type of biological aging trajectory. In theory, the genes influencing that variation can be identified if heritability is actually around 50%. This is because the genes are not so obscured by environmental noise that it becomes methodologically impossible to identify them. In the paper’s commentary, Ben Shenhar put it succinctly: high heritability encourages the search for gene variants that prolong lifespan in order to comprehend the biology of aging and, eventually, treat it therapeutically. Although that sentence is measured and cautious, the point it makes is not at all modest. It suggests that in the future, treatments based on knowledge of particular genetic pathways may significantly change people’s lifespans and, more importantly, their quality of life during those years.
It’s important to acknowledge the distance that still separates that future from the present. It is not the same as figuring out which genes are responsible for half of lifespan variation, comprehending how they interact, or knowing how to safely intervene. Researchers in other fields of genetic medicine have repeatedly been humbled by the enormous gap between a heritability estimate and a functional treatment. The history of ambitious longevity research is replete with discoveries that, in isolation, appeared revolutionary but turned out to be far more difficult to apply than the initial excitement suggested. Nevertheless, the Weizmann study seems methodologically cautious in ways that earlier research wasn’t, and this cautiousness is what makes the result more difficult to discount than most. Over the next ten years, it will be truly worthwhile to watch the field absorb and expand on this.
