Reacción a "Human life expectancy is more hereditary than previously thought, according to a study"

A key caveat is that the flagship estimate of 55% heritability depends on modeling choices and on conditioning the analysis on survival to specific “cutoff” ages (in one dataset, both twins must survive to older ages), which can affect correlations in nontrivial ways. I would therefore treat the 55% figure as a model-based estimate tied to a particular definition of “intrinsic” lifespan, not as a single settled fact. In this study, “extrinsic mortality” is defined as an age-independent background risk rather than external causes of death, which is important for interpreting the headline results. As a demographer, I usually think of extrinsic mortality as deaths from external or behavioral causes that are strongly patterned by age and by social conditions, which is quite a different concept.

Even if this work motivates the search for genetic predictors of longevity, and even if such efforts are successful, practical benefits from personalized interventions are likely to arrive unevenly and may reinforce existing socioeconomic inequalities in lifespan. By contrast, the largest and most durable gains in longevity have historically come from population-level improvements in living conditions, education, public health, and social protection, and from medical innovations only insofar as they diffuse widely across social groups. These “unexciting” interventions raise standards of living broadly, leading not only to longer lives but to healthier and more enjoyable lives, while also reducing inequalities in survival across social groups.