Carnes Bruce A, Olshansky S Jay, Grahn Douglas
Center on Aging, National Opinion Research Center, University of Chicago, 1155 E. 60th Street, Chicago, IL 60637, USA.
Biogerontology. 2003;4(1):31-45. doi: 10.1023/a:1022425317536.
Projections of duration of life for humans based on mathematical models have led some researchers to claim that there is no lower limit to death rates or upper limit to life expectancy, and that a life expectancy of 100 will be achieved in the 21st century. To assess the biological plausibility of these claims, we examined temporal aspects of biological phenomena in three mammalian species. Our examination revealed that: (1) physiological declines associated with reproduction consistently occur at ages that are less than one-third of the median age at death, (2) physiological parameters associated with aging in humans lose eighty percent of their functional capacity by age 80, and (3) young versus old individuals can be distinguished by the pathologies detected at death. The biological evidence suggests that organisms operate under warranty periods that limit the duration of life of individuals and the life expectancy of populations. We use these findings to discuss the issue of limits to the duration of life and the validity of mathematical models used to forecast human longevity.
基于数学模型对人类寿命的预测，使得一些研究人员宣称死亡率没有下限，预期寿命没有上限，并且在21世纪将实现100岁的预期寿命。为了评估这些说法在生物学上的合理性，我们研究了三种哺乳动物物种生物学现象的时间方面。我们的研究表明：（1）与繁殖相关的生理衰退持续发生在不到死亡年龄中位数三分之一的年龄段；（2）与人类衰老相关的生理参数到80岁时丧失其功能能力的80%；（3）年轻个体与年老个体可以通过死亡时检测到的病理状况加以区分。生物学证据表明，生物体在保修期内运行，这限制了个体的寿命以及种群的预期寿命。我们利用这些发现来讨论寿命期限的问题以及用于预测人类长寿的数学模型的有效性。
