Contrary to accepted wisdom, which assumes an exponential increase in mortality with age, death rates decelerate with age, not just for humans but also for insects, worms, yeastand automobiles.
In an article appearing in this weeks Science (Vaupel et. al., Biodemographic trajectories of Longevity, Science, vol. 280, 8 May 1998) senior author Prof. James W. Vaupel from the Max Planck Institute for Demographic Research in Rostock, Germany, presents the findings of research on longevity conducted over the last several years by members of an international team of demographers, biologists and statisticians. This study is one of the first to come out of the newly emerging field of biodemography.
Since 1950 there have been substantial, largely unexplained reductions in human mortality at older ages. And the rate of reduction has accelerated in most developed countries, especially since 1970. In 1990 there were about four to five times as many centenarians in these countries than there would have been if mortality after age 80 had stayed at 1960 levels. Death rates increase at a slowing rate after age 80. Mathematical analysis of the data indicates that death rates may level off at around 105 and even decline after age 110.
The decline in old-age mortality is not restricted to Homo sapiens. Vaupel et al. estimated age
trajectories of death rates for very large cohorts of four species of fruit flies, a parasitoid
wasp, a nematode worm, and bakers yeast. Despite substantial differences in the trajectories,
they share a key characteristic: mortality decelerates and, for the largest populations studied,
it even declines at older ages. The same seems to be true for old automobiles as well, which
Contact: James W. Vaupel