The Gompertz law is a relatively simple equation that describes the exponentially increasing mortality rates observed in an aging population. One fits the equation to existing epidemiological data by adjusting the value of two parameters, α and β. Researchers here use the results of age-slowing interventions in large populations of nematode worms to assign physical, biological meanings to the changes in α and β produced by the treatment of aging. As the researchers describe here, β is related to length of time spent in poor health in later life, while α is related to length of time spent in good health in earlier life.
In populations of many animal species, including humans, mortality rates increase exponentially with advancing age. The scale and rate of increase can be set by two parameters, α and β, respectively, of the Gompertz equation. Interventions that extend lifespan can reduce either or both parameters. A long-standing supposition resulting from use of the equation in human epidemiology is that β corresponds to biological ageing rate, and α to ageing-independent causes of mortality.
Here, we investigate the biological basis of α and β using the nematode Caenorhabditis elegans, through the combined study in populations and individuals of effects of life-extending interventions on mortality and age-changes in health. We demonstrate that reductions in β arise not from slowed biological ageing, but rather from expansion of decrepitude (gerospan) in longer-lived population members. In contrast, reductions in α better reflect healthspan expansion, an indicator of slowed biological ageing. Thus, our investigation presents a new, empirical understanding of the Gompertz parameters that inverts their traditional interpretations.
Link: https://doi.org/10.1038/s41467-026-71780-7
View the full article at FightAging
