Your lifespan may be more firmly rooted in your DNA than scientists previously believed. A study published in the journal Science by researchers at the Weizmann Institute of Science suggests that genetics accounts for roughly 50 percent of the differences in how long people live.
For years, the scientific consensus held that lifespan was primarily dictated by environmental factors and chance. Earlier studies frequently estimated that inherited factors accounted for only 10 to 25 percent of longevity variations.
"For many years, lifespan was attributed mainly to non-genetic factors, fueling skepticism about genetic determinants of longevity," said Ben Shenhar, who led the research team from the lab of Prof. Uri Alon.
To reach these findings, the team analyzed three extensive twin databases from Sweden and Denmark. Crucially, they included data from twins raised apart, which allowed researchers to isolate genetic influences from environmental variables.
Filtering out external causes
Previous estimates often faltered because they failed to distinguish between biological aging and "extrinsic mortality." This category includes deaths caused by accidents, infections, and other external environmental factors that can mask the true impact of an individual's genetic makeup.
To correct this, the researchers developed a new analytical model using simulations of virtual twins. By filtering out deaths linked to external causes, the team uncovered a significantly stronger genetic signal than previous methodologies allowed.
This high degree of heritability is consistent with other complex human traits, according to the study. The data also indicated that up to age 80, the risk of dying from dementia shows a heritability of approximately 70 percent, far outpacing the genetic link found in cancer or heart disease.
These results provide a new roadmap for medical research. If genetics plays a central role in longevity, it provides a stronger incentive for scientists to identify the specific gene variants that contribute to a longer life.
"If heritability is high, as we have shown, this creates an incentive to search for gene variants that extend lifespan, in order to understand the biology of aging and, potentially, to address it therapeutically," Shenhar said.
The research was supported by a coalition of organizations, including the Sagol Institute for Longevity Research, the Knell Family Institute for Artificial Intelligence, and the Moross Integrated Cancer Center.
