Long-run trends of human aging and longevity

Over the last 200 years, humans experienced a huge increase of life expectancy. These advances were largely driven by extrinsic improvements of their environment (for example, the available diet, disease prevalence, vaccination, and the state of hygiene and sanitation). In this paper, we ask whether future improvements of life expectancy will be bounded from above by human life span. Life span, in contrast to life expectancy, is conceptualized as a biological measure of longevity driven by the intrinsic rate of bodily deterioration. In order to pursue our question, we first present a modern theory of aging developed by bio-gerontologists and show that immutable life span would put an upper limit on life expectancy. We then show for a sample of developed countries that human life span thus defined was indeed constant until the mid-twentieth century but increased since then in sync with life expectancy. In other words, we find evidence for manufactured life span.     

Life Potential as a Basic Demographic Indicator

This paper proposes an indicator that integrates life expectancy with the demographic structure of the population for a given society. By doing this, we have a simple indicator of mortality and aging combined, which could be very useful for developed societies. As is widely known, life expectancy at birth is independent of the demographic structure of the population, and therefore is adequate for measuring overall mortality. However, it neglects to take into account the fact that as life expectancy increases society ages, and so looking at life expectancy alone can produce an overly optimistic view of the development process, especially if we pay attention to future sustainability. Aging can in fact affect quality of life and sustainability in the long run. The indicators for aging are usually very crude, such as providing information on the share of the population who are 65 and over. We propose a simple indicator that integrates life expectancy at different ages, not only at birth, with the demographic structure of the population at a given point in time. The indicator has an intuitive interpretation in terms of the life potential, or biological capital, of society; and given that it is a weighted average, its changes can be easily decomposed into reductions in mortality (gains in life expectancy) and aging for different age intervals.     

Potential support ratios: Cohort versus period perspectives

The ‘prospective potential support ratio’ has been proposed by researchers as a measure that accurately quantifies the burden of ageing, by identifying the fraction of a population that has passed a certain measure of longevity, for example, 17?years of life expectancy. Nevertheless, the prospective potential support ratio usually focuses on the current mortality schedule, or period life expectancy. Instead, in this paper we look at the actual mortality experienced by cohorts in a population, using cohort life tables. We analyse differences between the two perspectives using mortality models, historical data, and forecasted data. Cohort life expectancy takes future mortality improvements into account, unlike period life expectancy, leading to a higher prospective potential support ratio. Our results indicate that using cohort instead of period life expectancy returns around 0.5 extra younger people per older person among the analysed countries. We discuss the policy implications implied by our cohort measures.     

Facing up to uncertain life expectancy: The longevity fan charts

This article uses longevity fan charts to represent the uncertainty in projections of future life expectancy. These fan charts are based on a mortality model calibrated on mortality data for English and Welsh males. The fan charts indicate strong upward sloping trends in future life expectancy. Their widths indicate the extent of uncertainty in these projections, and this uncertainty increases as the forecast horizon lengthens. Allowing for uncertainty in the parameter values of the model adds further to uncertainty in life expectancy projections. The article also illustrates how longevity fan charts can be used to stress-test longevity outcomes.     

Trends in senescent life expectancy

The distinction between senescent and non-senescent mortality proves to be very valuable for describing and analysing age patterns of death rates. Unfortunately, standard methods for estimating these mortality components are lacking. The first part of this paper discusses alternative methods for estimating background and senescent mortality among adults and proposes a simple approach based on death rates by causes of death. The second part examines trends in senescent life expectancy (i.e., the life expectancy implied by senescent mortality) and compares them with trends in conventional longevity indicators between 1960 and 2000 in a group of 17 developed countries with low mortality. Senescent life expectancy for females rises at an average rate of 1.54 years per decade between 1960 and 2000 in these countries. The shape of the distribution of senescent deaths by age remains relatively invariant while the entire distribution shifts over time to higher ages as longevity rises.     

Longer Life and Population Growth

Enthusiasm about the prospect of large increases in human life expectancy is often dampened by fears that lower mortality will increase population size, hence population pressure. A simple mathematical model of life-cycle stretching demonstrates that if increased longevity is accompanied by later childbearing, a trend that is already underway, future declines in mortality will not increase population size.     

Beyond Material Explanations: Family Solidarity and Mortality,a Small Area‐level Analysis

Social solidarity, being embedded in a network of binding social relationships, tends to extend human longevity. Yet while average incomes in the Western world, and with them, life expectancies, have risen dramatically, the second demographic transition has occasioned a breakdown in traditional family forms. This article considers whether these trends in family life may have slowed the rise in life expectancy. I present a cross‐sectional analysis of Israeli statistical areas (SAs), for which I construct indexes of Standard of Living (SOL), Traditional Family Structure (TFS), and Religiosity (R). I show that (1) increases in all three of these indexes are associated with lower levels of mortality, (2) male mortality is more sensitive to differences in SOL and TFS than is female mortality, and (3) net of differences in SOL and TFS, there is no difference in the mortality levels of Arab and Jewish populations.     

The implications of increased survivorship for mortality variation in aging populations

The remarkable growth in life expectancy during the twentieth century inspired predictions of a future in which all people, not just a fortunate few, will live long lives ending at or near the maximum human life span. We show that increased longevity has been accompanied by less variation in ages at death, but survivors to the oldest ages have grown increasingly heterogeneous in their mortality risks. These trends are consistent across countries, and apply even to populations with record-low variability in the length of life. We argue that as a result of continuing improvements in survival, delayed mortality selection has shifted health disparities from early to later life, where they manifest in the growing inequalities in late-life mortality.     

The impact of heterogeneity in individual frailty on the dynamics of mortality

Life table methods are developed for populations whose members differ in their endowment for longevity. Unlike standard methods, which ignore such heterogeneity, these methods use different calculations to construct cohort, period, and individual life tables. The results imply that standard methods overestimate current life expectancy and potential gains in life expectancy from health and safety interventions, while underestimating rates of individual aging, past progress in reducing mortality, and mortality differentials between pairs of populations. Calculations based on Swedish mortality data suggest that these errors may be important, especially in old age.     

Relationships between period and cohort life expectancy: gaps and lags

This paper offers an empirical and analytic foundation for regarding period life expectancy as a lagged indicator of the experience of real cohorts in populations experiencing steady improvement in mortality. We find that current period life expectancy in the industrialized world applies to cohorts born some 40-50 years ago. Lags track an average age at which future years of life are being gained, in a sense that we make precise. Our findings augment Ryder's classic results on period-cohort translation.     

Steep increase in best-practice cohort life expectancy

We analyze trends in best-practice life expectancy among female cohorts born from 1870 to 1950. Cohorts experience declining rather than constant death rates, and cohort life expectancy usually exceeds period life expectancy. Unobserved mortality rates in non-extinct cohorts are estimated using the Lee-Carter model for mortality in 1960–2008. Best-practice cohort and period life expectancies increased nearly linearly. Across cohorts born from 1870 to 1920 the annual increase in cohort length of life was 0.43 years. Across calendar years from 1870 to 2008, the annual increase was 0.28 years. Cohort life expectancy increased from 53.7 years in the 1870 cohort to 83.8 years in the 1950 cohort. The corresponding cohort/period longevity gap increased from 1.2 to 10.3 years. Among younger cohorts, survival to advanced ages is substantially higher than could have been anticipated by period mortality regimes when these cohorts were young or middle-aged. A large proportion of the additional expected years of life are being lived at ages 65 and older. This substantially changes the balance between the stages of the life cycle.     

Relationships between period and cohort life expectancy: Gaps and lags

This paper offers an empirical and analytic foundation for regarding period life expectancy as a lagged indicator of the experience of real cohorts in populations experiencing steady improvement in mortality. We find that current period life expectancy in the industrialized world applies to cohorts born some 40–50 years ago. Lags track an average age at which future years of life are being gained, in a sense that we make precise. Our findings augment Ryder's classic results on period–cohort translation.     

Inequality in life expectancy, functional status, and active life expectancy across selected black and white populations in the United States

We calculated population-level estimates of mortality, functional health, and active life expectancy for black and white adults living in a diverse set of 23 local areas in 1990, and nationwide. At age 16, life expectancy and active life expectancy vary across the local populations by as much as 28 and 25 years respectively. The relationship between population infirmity and longevity also varies. Rural residents outlive urban residents, but their additional years are primarily inactive. Among urban residents, those in more affluent areas outlive those in high-poverty areas. For both whites and blacks, these gains represent increases in active years. For whites alone they also reflect reductions in years spent in poor health.     

Human Capabilities Versus Human Capital: Guaging the Value of Education in Developing Countries

The purpose of this study is to defend the view that education should be evaluated in terms of the capability to achieve valued functionings, rather than mental satisfaction or resources. In keeping with Amartya Sen’s capabilities approach we argue that mental satisfaction provides an inaccurate metric of well-being because of the phenomenon of adaptive preferences. Equally, resources cannot be used as a metric of well-being because of inequalities in the ability to convert income and commodities into valued functionings. Hence, interpreting education as a means to create human capital is also impoverished because it evaluates education solely in terms of the accumulation of resources. In order to provide evidence in support of the human capabilities approach we statistically examine the channels through which educational attainment affects the health functionings implied by life expectancy. Using panel data analysis for 35 developing countries for the years 1990, 1995 and 2000 we compare the health functionings (as indicated by life expectancy) that are achieved by the income growth generated by educational attainment, with the total health functionings that are achieved by educational attainment. We find that educational attainment (as indicated by average years of schooling) has a significant effect on life expectancy independently of its effect by way of income growth. A 1% increase in per capita income increases life expectancy by 0.073954% while a 1% increase in average years of schooling directly increases life expectancy by 0.055324%. Because it shows that income underestimates the health functionings achieved by educational attainment, our empirical findings lend support to the claim that the value of education should be measured in terms of the capability for functioning, rather than resources.     

Changing Life Expectancy and Health Expectancy Among Russian Adults: Results from the Past 20 Years

The decade following the collapse of the Soviet Union was characterized by wide fluctuations in Russian mortality rates, but since the early 2000s, life expectancy has improved progressively. Recent upturns in longevity have promoted policy debates over extending the retirement age in the country. However, whether observed gains in life expectancy are accompanied by improving health remains to be addressed. Using data from the 1994–2014 Russian Longitudinal Monitoring Survey of the Higher School of Economics, this study investigates trends over 20 years in healthy life expectancy (HLE) and illness-free life expectancy (IFLE) for men and women at adult ages. Analyses using the Sullivan method show that men and women at adult ages have experienced large increases in health expectancies during the post-Soviet period. Increases in HLE exceeded increases in total life expectancy for both genders. Further, health expectancies have evolved over time through cycles of increases and decreases, just like life expectancy. These results suggest increases in good-quality years among men and women at working ages, offering support for changing the official retirement age. The extent of the change in the retirement age, however, needs to be carefully considered, given that, despite recent improvements, the health expectancy of the Russian population still remains low.     

Active life expectancy estimates for the U.S. elderly population: A multidimensional continuous-mixture model of functional change applied to completed Cohorts, 1982–1996

An increment-decrement stochastic-process life table model that continuously mixes measures of functional change is developed to represent age transitions among highly refined disability states interacting simultaneously with mortality. The model is applied to data from the National Long Term Care Surveys of elderly persons in the years 1982 to 1996 to produce active life expectancy estimates based on completed-cohort life tables. At ages 65 and 85, comparisons with extant period estimates for 1990 show that our active life expectancy estimates are larger for both males and females than are extant period estimates based on coarse disability states.     

On the dynamics of the age structure,dependency, and consumption

We examine the effects of population aging due to declining fertility and rising elderly life expectancy on consumption possibilities in the presence of intergenerational transfers. Our analysis is based on a highly tractable continuous-time overlapping generations model in which the population is divided into three groups (youth dependents, workers, and elderly dependents) and lifecourse transitions take place in a probabilistic fashion. We show that the consumption-maximizing response to greater longevity in highly developed countries is an increase in fertility. However, with larger transfer payments, the actual fertility response will likely be the opposite, leading to further population aging.     

A statistical analysis of the life expectancy of the residents of our country, 1973-75]

Statistical analysis of life expectancy is important in assessing population health and its characteristics and in studying human diseases and natural population changes. Life tables are constructed and statistical analysis is performed retrospectively on data accumulated over a 3-year (1973-1975) period. The data were supplied by the Office of Cancer Prevention and Treatment of the Ministry of Health, which originated from 24 provinces, representing an accumulated population of 2.04 billion, with a total mortality of 15.29 million. Results show that life expectancy in China has greatly improved since Liberation. Thus, in 1935, the average life expectancy for Nanjing residents was under 35 years. In 1951, the average life expectancy for male and female residents of Shanghai were 42.74 and 46.76 years respectively. But for the 1973-1975 period, the average Chinese life expectancy was 63.62 years for males and 66.31 years for females, with higher life expectancy for coastal provinces than for inland provinces. Cardiovascular diseases (excluding arteriosclerotic heart diseases), malignant tumors, and cerebrovascular diseases were the major causes of death in regions with higher life expectancy, while respiratory diseases, infectious diseases, and diseases of the newborn were the major causes of death in regions with lower life expectancy.     

A Biodemographic Interpretation of Life Span

The life span of individuals and the life expectancy of the populations they comprise have always been topics of interest to scientists and the lay population. In modern times, forecasts of life span and life expectancy have become particularly important public policy issues because of their influence on the future solvency of age‐entitlement programs. The authors present a brief discussion of the origin of the notion of life span, discuss its relevance and importance in light of recent developments in the emerging field of the biodemography of aging, and explore the theoretical and biological forces that influence the duration of life of sexually reproducing species.     

1994～2004年中国老年人的生活自理预期寿命及其变化

本文应用2004年和1994年国家统计局全国人口变动抽样调查中有关老年人生活自理能力的数据,采用Sullivan法对老年人的生活自理预期寿命进行了分析,并且比较了1994年到2004年生活自理预期寿命的变化。研究发现,2004年中国男性老年人平均有1.5年生活不能自理,女性老年人平均为2.5年。随着年龄的增长,中国老年人的生活自理预期寿命占余寿的比重也在逐渐下降。女性老年人的预期寿命比男性高,生活自理预期寿命在60~80岁也高于男性,但是85岁及以上女性的生活自理预期寿命低于男性,而且女性老年人生活自理预期寿命占余寿的比重在整个老年阶段均低于男性老年人。从10年间的变化看,中国老年人的预期寿命和生活自理预期寿命都有所增长,但是生活自理预期寿命在余寿中的比重反而下降了,而且随年龄的增长,下降得也越来越快,男性和女性均呈现同样的态势。就平均水平而言,健康状况改善的程度低于寿命的延长,高龄女性老年人在这个方面尤其处于劣势。