保险公司长寿风险度量

本文梳理了几种重要的动态死亡率预测模型,给出了长寿风险度量的三种方法,选取了保险公司及国家统计局公布的人口死亡率数据,度量了保险公司的两类长寿风险,对不同方法下长寿风险的度量结果进行比较,并分析了极限年龄与折现率变动对长寿风险影响的敏感性。研究发现：基于保险公司经营稳健性的视角,第一类长寿风险的度量应采用随机模拟法,第二类长寿风险的度量应采用标准公式法;极限年龄的变动对长寿风险的影响较小,保险公司无上调经验生命表极限年龄的必要;长寿风险对折现率的变动较为敏感,提高折现率,保险公司长寿风险显著降低。     

Child Mortality and Environment in Developing Countries

This paper studies child mortality and fertility in 61 developing countries including the Central Asian Republics (CARs). To control for simultaneity, an estimated value of fertility was used in the mortality equation and a final specification included only exogenous socio-economic, health and environmental variables. We confirm the importance of female literacy in explaining both fertility and mortality, and also find a measure of consumption for the poorest share of the population to be significant, while controlling for nutrition, health expenditure, and income distribution. Incidence of tuberculosis and female agricultural population proxy for environmental impacts, but in spite of these controls, approximately 41% additional mortality was estimated due to living in the CARs. The results fill gaps in the literature: we use a wider range of socio-economic and environmental health variables than previously in an encompassing analysis of mortality and fertility, and find evidence of excessive mortality in the CARs most likely linked to environmental degradation in the region.

中国老人丧偶与其死亡风险的关系分析——配偶照顾的作用

文章基于中国老人健康长寿影响因素研究数据(1998~2005),利用Cox比例风险模型考察了中国老人丧偶对其死亡风险的影响机制,并深入分析了配偶照顾因素在降低老人死亡风险中的作用。结果发现:丧偶与死亡风险具有显著的关系,一般而言,长期丧偶老人的死亡风险显著地高于长期有偶的老人。而且,除了高龄女性老人之外,老人在丧偶初期,其死亡风险会大大增加。在解释丧偶是如何影响老人的死亡风险时,配偶的照顾是一个非常重要的因素,在控制配偶照顾的条件下,丧偶者与有偶者的死亡风险差异会大幅下降,这说明来自配偶的生活照顾对于老人的寿命发挥着重要影响。此外,本研究也发现配偶照顾的作用具有显著的性别差异和年龄组差异。     

Adaptive autoregressive priors for area and time structured mortality data

Mortality counts by age and area are relevant to obtaining small area life tables and summary statistics such as life expectancy. A Bayesian approach to small area life tables is proposed here based on the principle of smoothing (or “pooling strength”) over adjacent ages or areas. Several schemes have been suggested to reflect dependence between age categories x or areas i  , such as conditional autoregressive priors based on the principle of local smoothing, determined by adjacency of age groups or spatial proximity. It is argued here that a more flexible approach is to allow a mix of local and global smoothing over age groups and areas, as determined by the data and additional parameters κ∈[0,1]$\kappa \in [0,1]$ and λ∈[0,1]$\lambda \in [0,1]$ for age and area, respectively. An extension is also proposed to reflect the fact that the appropriate mix between local and global smoothing may not be constant across age bands or across the region being studied. For example, local spatial smoothing will not be appropriate if an area is disparate from its neighbours (e.g. in terms of social distance), and so area specific mixing parameters _λi${\lambda }_i$ are introduced. The _λi${\lambda }_i$ may be modelled by logit regression on observed sources of disparity between neighbouring areas. The application considers small area life tables for males over 625 small areas (electoral wards) in London over 2003–2005.     

Effects of plant density on the survival rate of cabbage pests

The population density of herbivores depends on the spatial scale as well as the temporal scale. In a small-scale, short-term experiment, the number of individuals entering from the surrounding area will be most influential in determining the herbivore density. In large-scale, long-term experiments, however, the density of herbivores will rather be influenced by the survival rate of individuals inside the field because most of the herbivorous population derives from the parents that developed inside the field. If we want to predict the large-scale long-term density of herbivores, therefore, emphasis should be placed on the estimation of survival rate. To elucidate the effects of plant density on the large-scale long-term abundance of cabbage pests, we examined the survival rates of three lepidopterous pests, the small white butterfly Pieris rapae crucivora Boisduval (Pieridae), the beet semi-looper Autographa nigrisigna (Walker) (Noctuidae), and the diamondback moth Plutella xylostella (Linnaeus) (Yponomeutidae) under two levels of plant spacing (sparse plot, 2 m × 2 m interval; dense plot, 0.5 m × 0.5 m interval). The experiment with four blocks was repeated in two seasons. The number of eggs per plant was larger in the sparse plots than in the dense plots for all species. The survival rate of eggs and larvae, on the contrary, was lower in the sparse plots than in the dense plots. The lower survival rate of eggs in the sparse plots was mainly caused by the density dependency, while the lower survival rate of larvae in the sparse plots was mainly caused by the direct effects of plant density. It was thus suggested that the density of herbivores may become lower in the sparsely planted field in the long run because of the higher mortality of larvae. Received: September 16, 1998 / Accepted: March 22, 1999     

Theoretical considerations on the C-D effect in self-thinning plant populations

A model for describing the competition–density (C-D) effect in self-thinning populations was developed on the basis of the following three basic assumptions: (1) the growth of mean phytomass follows a general logistic equation; (2) final yield is independent of initial population density; and (3) there exists a functional relationship between actual and initial population densities at any given time. The resultant equation takes the same reciprocal form as the reciprocal equation of the C-D effect derived from Shinozaki–Kira's theory (i.e., the logistic theory of the C-D effect), which deals with the density effect in nonself-thinning populations. However, one of the two time-dependent coefficients is quite different in mathematical interpretation between the two reciprocal equations. The reciprocal equation for self-thinning populations is essentially the same as the reciprocal equation assumed in the derivation of the functional relationship between actual and initial population densities. The establishment of the reciprocal equation is supported by the empirical facts that the reciprocal relationship between mean phytomass and population density is discernible in not only nonself-thinning populations but also in self-thinning populations. The present model is expected to systematically interpret underlying mechanisms between the C-D effect, which is observed at a time constant among populations with various initial densities, and self-thinning, which is observed along a time continuum in a given population. Received: August 5, 1998 / Accepted: January 7, 1999     

Adult mortality differentials associated with cigarette smoking in the USA

Although cigarette smoking has been extensively researched, surprising little knowledge has been produced by demographers using demographic perspectives and techniques. Thus, this paper contributes to the literature by extending a demographic framework to an important behavior for mortality research: cigarette smoking. In earlier works, the authors used nationally-representative data to show that cause of death patterns varied by smoking status and that multiple causes of death characterized smokers moreso than non-smokers. The present work extends previous analysis by estimating smoking status mortality differentials by underlying and multiple causes of death and by age and sex. Data from the 1986 National Mortality Followback Survey are related to data from the 1985 and 1987 National Health Interview Survey supplements to assess the smoking-related mortality differentials. We find that cigarette smoking is associated with higher mortality for all population categories studied, that the smoking mortality differentials vary across the different smoking status categories and by demographic group, and that the mortality differentials vary according to whether underlying cause or multiple cause patterns of death are examined. Moreover, the multiple cause analysis highlights otherwise obscured smoking-mortality relations and points to the importance of respiratory diseases and cancers other than lung cancer for cigarette smoking research.     

A comparison of models for dynamic life tables. Application to mortality data from the Valencia Region (Spain)

The graduation of mortality data aims to estimate the probabilities of death at age x, q ( x ), by means of an age-dependent function, whose parameters are adjusted from the crude probabilities that are directly obtainable from the data. However, current life tables have a problem, the need for periodic updates due to changes in mortality over short periods of time. The table containing mortality rates for different ages in different years, q ( xt ), is called a dynamic life table, which captures mortality variation over time. This paper proposes a review of the most commonly used dynamic models and compares the results obtained by each of them when applied to mortality data from the Valencia Region (Spain). The result of the comparison leads us to the conclusion that the Lee-Carter method offers the best results for both sexes, while that based on Heligman and Pollard functions provides the best fit for men alone. Our working method is of additional interest as it may be applied to mortality data for a wide range of ages in any geographical location, allowing the most appropriate dynamic life table to be selected for the case at hand.     

孕产妇死亡健康公平性分析

文章利用2000～2005年全国卫生统计年报中孕产妇死亡情况有关资料,计算了以孕产妇死亡率为基础的一系列健康公平性指标,分析了2000～2005年间我国孕产妇死亡的健康公平性。研究结果从人群归因危险度百分比、集中指数、集中曲线等指标反映出在我国孕产妇死亡存在分布的不均衡。2000～2005年我国孕产妇死亡在地区间及省际的差距没有明显变化,即不公平现象6年间没有得到改善。     

Bootstrap方法在死亡模型中的应用

 由于不同国家死亡率改善现象不同,世界各国所使用的死亡率模型皆不尽相同,而且不同年龄段的死亡率模型也不同。实际中,我们常常采用Gompertz模型、Makeham模型、Weibull模型等拟合高年龄段人口的死亡率,但是因高年龄段人口的死亡数据资料不够充分,较少有人以统计的观点给出模型适合性的检验过程。因此本研究提出利用Bootstrap方法检验死亡模型假设的方法,包括模型适合性的检验、参数估计、参数假设检验等。最后,本文应用中国1997－2007年65－89岁人口的粗死亡率数据,提出适合的死亡模型,然后给出利用Bootstrap方法进行死亡模型检验的全过程。