Study Finds 55% Genetic Role in Lifespan

A new study published in the journal Science has found that genetics may influence human lifespan far more than previously estimated, accounting for about 55 percent of variations when external causes of death are excluded. Researchers from the Weizmann Institute of Science in Israel analyzed twin and sibling data from Scandinavia and the United States, suggesting that intrinsic biological aging processes, driven largely by genes, play a dominant role in how long people live in modern environments.

The study, led by systems biologist Uri Alon, challenges the long-held view that lifespan is only 20 to 25 percent heritable, with the rest determined by lifestyle and environmental factors. Previous estimates, drawn from historical populations, were skewed by high rates of extrinsic mortality, such as infections, accidents, and injuries, which masked genetic influences. By using mathematical models to isolate deaths from these external causes, the team recalibrated heritability figures from twin studies conducted in Sweden and Denmark.

Alon and his colleagues examined mortality data from Swedish twins born between 1900 and 1935, a period marked by advances in sanitation and medicine...