New Insights Into The Enigma Of Lengthening...( suggests that although living...)

As far as living organisms are concerned, these findings come as a big surprise in light of the traditional view that posits maximum life-spans. According to this theory, the postreproductive span of life should be short because there is no selection against mutations that are not expressed until reproductive activity has ceased.

While it is not clear how to reconcile these findings with theories about aging, the authors present three biodemographic insightsconcerning the correlation of death rates across age, individual differences in survival chances, and induced alterations in age-patterns of fertility and mortalitythat offer clues and suggest avenues for future research.

These three concepts can be tied together by a general question: how important are an individuals "survival attributes" (persistent characteristics, innate or acquired, that affect survival chances) as opposed to current conditions in determining the chance of death? An analysis of data on Danish twins suggests that about 50% of the variation in human life-spans after age 30 can be attributed to survival attributes that are fixed by the time an individual is 30; a third to a half of these attributes are genetic and half to two-thirds nongenetic (related to, for example, socioeconomic status, disease history, etc.). The model used for this analysis indicates that the importance of survival attributes may increase with a persons life expectancy. Research over the next decade may resolve the question of how many survival attributes account for most of the
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Contact: James W. Vaupel
jwv@demogr.mpg.de
+49-381-2081-102
Max-Planck-Gesellschaft
7-May-1998