Carnes Bruce A
The University of Oklahoma Health Sciences Center, D.W. Reynolds Department of Geriatric Medicine, 921 N.E. 13th Street (11G), Oklahoma City, OK, USA.
Ann N Y Acad Sci. 2007 Oct;1114:14-22. doi: 10.1196/annals.1396.045.
Although mortality and longevity are inherently biological phenomena, their study has historically been the purview of demography and the actuarial sciences. An infusion of biological thinking into these disciplines transforms demography into biodemography and provides expectations and coherency to observations on age-determined mortality that would not be explainable otherwise. Comparative biology teaches us that reproduction is life's solution to the inevitability of death in the hostile environments of Earth. That solution, however, places a higher priority on investing physiological resources into reproduction that could otherwise have been used to maintain the soma (body) longer. As such, aging is an inescapable but inadvertent byproduct of imperfect maintenance and its attendant surveillance and repair. Biology also reveals that while bodies are not designed to fail, neither are they designed for extended operation. In other words, bodies are subject to biological warranty periods for normal operation. For sexually reproducing species, that warranty period includes the time from conception to sexual maturity, the production and nurturing of offspring, and a period of grand-parenting in some species. Humans are the only species capable of exploiting the loophole in the biological contract of life (bodies that are not designed to fail). Human ingenuity (science, medicine, public health) has produced interventions that manufacture survival time by delaying death, and in so doing, has created a phenomenon never before seen in the history of life-population aging (and all the societal and health consequences that go with it).
尽管死亡率和寿命本质上是生物学现象，但对它们的研究在历史上一直属于人口统计学和精算科学的范畴。将生物学思维融入这些学科，会把人口统计学转变为生物人口统计学，并为关于年龄决定的死亡率的观察提供预期和连贯性，否则这些观察将无法解释。比较生物学告诉我们，繁殖是生命在地球恶劣环境中应对死亡必然性的方式。然而，这种方式将更高的优先级置于将生理资源投入繁殖，而这些资源原本可用于更长时间地维持躯体（身体）。因此，衰老是维护不完善及其伴随的监测和修复所产生的不可避免但无意的副产品。生物学还揭示，虽然身体并非注定会失败，但它们也不是为长期运转而设计的。换句话说，身体正常运转存在生物学质保期。对于有性繁殖物种而言，该质保期包括从受孕到性成熟的时间、后代的生育和养育，以及某些物种中的一段祖父母育儿期。人类是唯一能够利用生命生物学契约中的漏洞（并非注定会失败的身体）的物种。人类的智慧（科学、医学、公共卫生）产生了通过延迟死亡来制造生存时间的干预措施，这样做创造了生命史上从未见过的一种现象——人口老龄化（以及随之而来的所有社会和健康后果）。
