Overview
- Using Swedish and Danish twin registries and U.S. siblings of centenarians, researchers estimate lifespan heritability at roughly 50–55% once external causes are excluded.
- Earlier figures of 10–25% likely reflected historical cohorts where infections, accidents and other hazards masked genetic effects.
- Dementia and cardiovascular mortality show stronger familial patterns, whereas many cancers appear less influenced by inherited factors.
- The study suggests lifestyle shifts may move life expectancy by only a few years, though experts note healthy habits can still change outcomes by up to a decade.
- Authors and outside commentators highlight model sensitivity, grey zones in classifying causes of death and limited generalisability beyond Scandinavian cohorts, with the findings encouraging broader searches for longevity genes.