Weiss K M
Department of Anthropology, Pennsylvania State University, University Park 16802.
Demography. 1990 May;27(2):185-206.
A population is composed of individuals who are heterogeneous in their susceptibility to death and disease. This heterogeneity is reflected in the age-specific incidence or mortality (hazard) function. This variation has typically been hidden--that is, not measured directly--and has generally been modeled in a purely empirical statistical way, because there is no theory in demography for the distribution of frailty. A substantial fraction of variation in frailty, however, has an underlying genetic basis, for which there is a formal theory. This theory, based on evolutionary biology and on the nature of mendelian transmission, provides prior constraints on the distribution of variation in the population as well as providing methods for identifying genes involved in many important diseases. The accumulating effects of environmental exposures with age are another major component of variation in frailty. In some important instances, this variation and its effect on the age-specific hazard function can also be understood in terms of cause-specific biological processes. These biological considerations may enable demographers to model frailty, and thus mortality, in a better way.
一个人群是由在死亡和疾病易感性方面存在异质性的个体组成。这种异质性反映在特定年龄的发病率或死亡率（风险）函数中。这种变异通常是隐藏的——也就是说，没有直接测量——并且一般是以纯粹经验性的统计方式进行建模，因为在人口统计学中没有关于脆弱性分布的理论。然而，很大一部分脆弱性变异具有潜在的遗传基础，对此存在一个正式的理论。这个基于进化生物学和孟德尔遗传本质的理论，为人群中变异的分布提供了先验约束，同时也提供了识别与许多重要疾病相关基因的方法。随着年龄增长，环境暴露的累积效应是脆弱性变异的另一个主要组成部分。在一些重要情况下，这种变异及其对特定年龄风险函数的影响也可以从特定病因的生物学过程角度来理解。这些生物学考量可能使人口统计学家能够更好地对脆弱性进而对死亡率进行建模。
