Are improvements in senescent life expectancy accelerating or decelerating?

描述（由申请人提供）：该项目的主要目标是确定近几十年来发达国家老年人预期寿命的增长是在加速还是在减速。以传统的出生时预期寿命衡量的寿命在发达国家已经上升了大约两个世纪，但改善的速度正在放缓，对未来的趋势存在相当大的分歧。悲观主义者认为，我们正接近预期寿命的极限。相比之下，乐观主义者则认为，由于老年人的死亡率正在迅速下降，这种改善将永无止境。这些关于未来的对立观点源于对近期死亡率趋势的分歧。拟议的研究将试图通过评估27个发达国家老年人预期寿命的最新趋势来解决这一争议。具体目标是：1)制定/确定一套老年预期寿命趋势指标。提出了五项指标：a)在没有非衰老死亡率的情况下，出生时预期寿命。这将被视为参考指标；B) 65岁时的预期寿命；C) 65岁调整预期寿命；D) 65岁以上年龄组死亡率的年龄变化；e) 65岁以上按年龄分列的死亡率生命表分布的成人模式。2)根据这5个指标得出老年人预期寿命趋势的实证估计。所有经验性估计都将根据1950年以后所有可得年份27个人口的男女死亡率数据库的数据得出。3)检验关于1950年以来五个指标趋势的异同的三个假设。4)估计老年死亡年龄变化的趋势，并评估其对老年预期寿命趋势的影响。

DESCRIPTION (provided by applicant): The project's main objective is to determine whether increases in senescent life expectancy in recent decades are accelerating or decelerating in developed countries. Longevity as measured by the conventional life expectancy at birth has risen for about two centuries in the developed world, but the pace of improvement is decelerating and there is considerable disagreement about future trends. Pessimists believe we are approaching limits to life expectancy. In contrast, optimists expect continued improvements with no limits because mortality rates at older ages are declining rapidly. These opposing views about the future are rooted in disagreement about recent trends in mortality. The proposed study will attempt to resolve this controversy by assessing recent trends in senescent life expectancy in 27 developed countries. Specific aims are: 1) Develop/identify a set of indicators of trends in senescent life expectancy. Five indicators are proposed: a) life expectancy at birth in the absence of non-senescent mortality. This will be considered the reference indicator; b) life expectancy at age 65; c) adjusted life expectancy at age 65; d) age shift in the force of mortality at ages 65+; and e) the adult mode of the life table distribution of death rates by age above age 65. 2) Obtain empirical estimates of trends in senescent life expectancy based on these five indicators. All empirical estimates will be derived from data in the Human Mortality Database for females and males in 27 populations for all available years after 1950. 3) Test three hypotheses about similarities and differences in trends in the five indicators since 1950. 4) Estimate trends in the variation in the age at senescent death and assess their impact on trends in senescent life expectancy. Project Narrative: Rapid aging of populations in the industrialized world has led to growing demand for more accurate projections of mortality and of the size of the population of elderly. The proposed research examines alternative indicators of trends in senescent life expectancy to shed light on the ongoing controversy about future trends in life expectancy at birth. This analysis is expected to result in more accurate estimates of current trends in senescent life expectancy thus providing the basis for more accurate and more robust long-range projections of mortality and of the future cost of pension and health care systems.