Institute for Social and Preventive Medicine (IUMSP), University Hospital and Faculty of Medicine, Lausanne, Switzerland.
Popul Health Metr. 2010 Jun 9;8:18. doi: 10.1186/1478-7954-8-18.
The ongoing increase in life expectancy in developed countries is associated with changes in the shape of the survival curve. These changes can be characterized by two main, distinct components: (i) the decline in premature mortality, i.e., the concentration of deaths around some high value of the mean age at death, also termed rectangularization of the survival curve; and (ii) the increase of this mean age at death, i.e., longevity, which directly reflects the reduction of mortality at advanced ages. Several recent observations suggest that both mechanisms are simultaneously taking place.
We propose a set of indicators aiming to quantify, disentangle, and compare the respective contribution of rectangularization and longevity increase to the secular increase of life expectancy. These indicators, based on a nonparametric approach, are easy to implement.
We illustrate the method with the evolution of the Swiss mortality data between 1876 and 2006. Using our approach, we are able to say that the increase in longevity and rectangularization explain each about 50% of the secular increase of life expectancy.
Our method may provide a useful tool to assess whether the contribution of rectangularization to the secular increase of life expectancy will remain around 50% or whether it will be increasing in the next few years, and thus whether concentration of mortality will eventually take place against some ultimate biological limit.
在发达国家，预期寿命的持续增长与生存曲线形状的变化有关。这些变化可以由两个主要的、不同的组成部分来描述：（i）过早死亡率的下降，即死亡集中在某些高平均死亡年龄值附近，也称为生存曲线的矩形化；（ii）平均死亡年龄的增加，即长寿，这直接反映了高龄死亡率的降低。最近的一些观察结果表明，这两种机制同时发生。
我们提出了一组指标，旨在量化、分解和比较矩形化和长寿增加对预期寿命的长期增长的各自贡献。这些指标基于非参数方法，易于实施。
我们用 1876 年至 2006 年瑞士死亡率数据的演变来说明该方法。使用我们的方法，我们能够说，长寿和矩形化的增加各自解释了预期寿命长期增长的约 50%。
我们的方法可以提供一个有用的工具，以评估矩形化对预期寿命的长期增长的贡献是否将保持在 50%左右，或者它是否将在未来几年内增加，以及死亡率的集中是否最终会达到某些最终的生物学极限。
