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.     

中国老年人口健康预期寿命差异的分解研究

健康预期寿命是反映人群健康长寿的重要指标,健康预期寿命差异反映了一个国家或地区的健康不平等状况。利用多状态生命表分析了中国老年人口健康预期寿命在过去十余年间的趋势与变动,并通过夏普利值分解法测算了人口社会学等11类因素对老年人口健康预期寿命差异的具体贡献值。得到以下四项重要研究结论:第一,从2005年到2018年,中国老年人口健康预期寿命差异的程度略有增加,女性、农村群体相比对应群体差距始终较高;泰尔指数分解发现,组内不平等(而非组间不平等)是造成上述差异的主要原因;老年人口健康预期寿命的性别差异呈现出高龄老人缩小而低龄老人扩大的趋势。第二,婚姻状况是健康预期寿命变动最重要的影响因素,但影响程度呈现逐年下降趋势,反之,受教育程度的影响在逐年上升;进一步将11类影响因素归类后发现:"个体特征"是最重要的影响因素,"经济因素"和"行为因素"的重要性次之,"环境因素"的影响最小。第三,上述影响因素对中国老年人口健康预期寿命的影响总体呈上升趋势,分城乡、分性别后依然呈现出相同的特征。最后,各因素在不同城乡、性别、婚姻状态的群体中的影响存在异质性。     

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.     

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.     

Is Health Wealth? Results of a Panel Data Analysis

The objective of this paper is to determine whether health (measured by life expectancy at birth) contributes to economic growth and the functional form in which it influences per capita income. This links our study to the debate between neo-classical and endogenous growth theorists on whether investment in human capital can sustain growth indefinitely. Data on 216 countries for the period 1980–2009 has been obtained from World Development Indicators dataset. This enables us to focus on a period characterized by globalization and demographic transition manifested in the form of population graying. Our findings confirm the importance of investment in human capital. But, in contrast to conclusions of endogenous growth models, we find evidence that benefit from increasing longevity tapers off. We conclude by pointing out that it is necessary to extend this study further by incorporating other dimensions of health that are not captured by life expectancy.     

A Realist View of Aging,Mortality, and Future Longevity

Differences in methodology and philosophy have led scientists analyzing the same mortality data to arrive at very different conclusions about the behavior of mortality trajectories, the nature of aging, and the future of human longevity. This note describes the authors’views on these issues, which taken together can be termed a “realist” position. In this view, life expectancy is unlikely to exceed an average of 85 years absent significant advances in the control of aging. We identify a number of myths that have been attached to our work: 1) Reaching an average life expectancy of 85 years is a pessimistic outlook for human longevity, 2) Species possess an intrinsic mortality schedule that cannot be modified by human intervention, 3) Realist scenarios of the future course of human longevity are based on notions of biological determinism, 4) Realists assert that there is an age beyond which there can be no survivors, 5) Hypothesized biological barriers to longer life spans have been scientifically studied and refuted, and 6) Realists claim that life expectancy at birth cannot exceed 85 years. In dispelling these myths, we hope to provide a more accurate representation of our school of biodemographic thought.     

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.     

Using Subjective Expectations to Forecast Longevity: Do Survey Respondents Know Something We Don’t Know?

Old-age mortality is notoriously difficult to predict because it requires not only an understanding of the process of senescence-which is influenced by genetic, environmental, and behavioral factors-but also a prediction of how these factors will evolve. In this paper I argue that individuals are uniquely qualified to predict their own mortality based on their own genetic background, as well as environmental and behavioral risk factors that are often known only to the individual. Given this private information, individuals form expectations about survival probabilities that may provide additional information to demographers and policymakers in their challenge to predict mortality. From expectations data from the 1992 Health and Retirement Study (HRS), I construct subjective, cohort life tables that are shown to predict the unusual direction of revisions to U.S. life expectancy by gender between 1992 and 2004: that is, for these cohorts, the Social Security Actuary (SSA) raised male life expectancy in 2004 and at the same lowered female life expectancy, narrowing the gender gap in longevity by 25% over this period. Further, although the subjective life expectancies for men appear to be roughly in line with the 2004 life tables, the subjective expectations of women suggest that female life expectancies estimated by the SSA might still be on the high side.     

Long-term trends in the longevity of scientific elites: evidence from the British and the Russian academies of science

National science academies represent intellectual elites and vanguard groups in the achievement of longevity. We estimated life expectancy (LE) at age 50 of members of the British Royal Society (RS) for the years 1670-2007 and of members of the Russian Academy of Sciences (RAS) for the years 1750-2006. The longevity of academicians was higher than that of their corresponding national populations, with the gap widening from the 1950s. Since the 1980s, LE in the RS has been higher than the maximum LE among all high-income countries. In each period, LE in the RS was greater than in the RAS, although since the 1950s it has risen in parallel in the two academies. This steep increase shared by academicians in Britain and Russia suggests that general populations have the potential for a substantial increase in survival to high ages.     

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.     

Modeling and Forecasting Health Expectancy: Theoretical Framework and Application

Life expectancy continues to grow in most Western countries; however, a major remaining question is whether longer life expectancy will be associated with more or fewer life years spent with poor health. Therefore, complementing forecasts of life expectancy with forecasts of health expectancies is useful. To forecast health expectancy, an extension of the stochastic extrapolative models developed for forecasting total life expectancy could be applied, but instead of projecting total mortality and using regular life tables, one could project transition probabilities between health states simultaneously and use multistate life table methods. In this article, we present a theoretical framework for a multistate life table model in which the transition probabilities depend on age and calendar time. The goal of our study is to describe a model that projects transition probabilities by the Lee-Carter method, and to illustrate how it can be used to forecast future health expectancy with prediction intervals around the estimates. We applied the method to data on the Dutch population aged 55 and older, and projected transition probabilities until 2030 to obtain forecasts of life expectancy, disability-free life expectancy, and probability of compression of disability.     

Greater Happiness for a Greater Number: Did the Promise of Enlightenment Come True?

In the eighteenth century ‘Enlightened’ thinkers challenged the belief that happiness exists only in Heaven. They claimed that happiness is possible in earthly life and foresaw that greater happiness would be achieved using reason. Did this promise of greater happiness come true? Several scholars doubt that we have become any happier and some claim that happiness has declined. These critical claims are tested using the time trend data available in the World Database of Happiness, which cover the period 1950–2010 and involve 1531 data points in 67 nations yielding 199 time-series ranging for 10 to more than 40 years. The analysis reveals that happiness has risen in most nations. The average yearly rise in the 67 nations was +0.012 on scale 0–10, which equals a rise of one full point every 83 years. At this rate happiness must have improved by more than two points over the past two centuries and, together with increasing longevity, this denotes an unprecedented rise in happy life years.     

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.     

近50年来世界人口期望寿命的演变轨迹

进入21世纪以来,全球人口已经突破60亿,但是人口增长速度明显减慢。许多国家已经完成了人口转变,其总和生育率在更替水平以下。与此同时,人口健康状况得到明显改善,死亡水平显著降低,期望寿命在不断提高。本文利用联合国人口司发布的192个国家人口死亡信息,系统分析了世界人口平均期望寿命在过去50年里的演变态势、区域差异以及演变模式。结果显示世界人口期望寿命经历了半个多世纪的持续增长,有50%以上的人口或国家平均期望寿命达到了70岁。演变轨迹呈多样化的发展模式,区域发展不平衡。欠发达地区总体上较发达地区增幅大,人口比重上升幅度也很显著。人均期望寿命增幅最大的是亚洲国家,非洲国家与世界不同步,而且区域内差异较大。     

An empirical model to predict arsenic pollution affected life expectancy

A robust, globally implementable and simple empirical model to predict the arsenic pollution affected life expectancy using a stepwise regression was developed. Life expectancy calculated using a life table technique requires crude death rates data that are not available for small administrative units, complex calculations and does not consider socioeconomic parameters. Hence, a model was needed to forecast the impact of arsenic pollution and socioeconomic parameters on life expectancy for locations with limited data availability. A linear multiple regression technique was used to develop an empirical model to predict arsenic pollution affected life expectancy at birth. The model was calibrated using nine arsenic polluted administrative blocks of district Murshidabad, West Bengal, India and tested independently for three other arsenic polluted blocks of the same district. The R ² values for the plot of actual versus predicted life expectancy at birth were 0.98 for calibration, testing and independent validation. The model is complementary to the life table technique and offers a means to assist planning by public health engineers and health policy makers to mitigate arsenic pollution on a community priority basis.     

Horizontal and Vertical Equity Objectives of Child Benefit Systems: An Empirical Assessment for European Countries

The present study investigates the determinants of life expectancy in the presence of economic misery using Pakistan’s time series data over the period of 1972–2012. The stationary properties of the variables are examined by applying unit root test accommodating structural breaks. The ARDL bounds testing approach to cointegration is applied to examine the long run relationship between the variables. Our findings show that cointegration between the variables is confirmed. Moreover, health spending improves life expectancy. Food supply contributes to life expectancy. A rise in economic misery deteriorates life expectancy. Urbanization enhances life expectancy while illiteracy declines it. The causality analysis reveals that life expectancy is Granger cause of health spending, food supply, economic misery, urbanization and illiteracy. This paper opens up new insights for policy making authorities to consider the role of economic misery while formulating comprehensive economic policy to improve life expectancy in Pakistan.     

The threshold hypothesis: evidence from less developed Latin American countries, 1950 to 1980

Historical research among European countries finds large differences in the level of social, economic or demographic development among countries, or regions within countries at the time marital fertility rates began their decline from traditional high levels. This research tests a threshold hypothesis which holds that fertility will decline from traditional high levels if threshold levels of life expectancy and literacy are surpassed. Using a pooled regression analysis of 1950, 1960, 1970 and 1980 crude births rates (CBRs) in 20 less developed Latin American countries, in conjunction with 10-year lagged measures of social, economic and family planning program development, analyses reveal statistically significant effects of passing Beaver's (1975) threshold levels of 1950 literacy, or 1950 life expectancy, that are independent of levels of lagged literacy (or lagged life expectancy), economic and family planning program development, as well as measures that control period effects.     

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.     

Changes in the age dependence of mortality and disability: Cohort and other determinants

Though the general trend in the United States has been toward increasing life expectancy both at birth and at age 65, the temporal rate of change in life expectancy since 1900 has been variable and often restricted to specific population groups. There have been periods during which the age- and gender-specific risks of particular causes of death have either increased or decreased. These periods partly reflect the persistent effects of population health factors on specific birth cohorts. It is important to understand the ebbs and flows of cause-specific mortality rates because general life expectancy trends are the product of interactions of multiple dynamic period and cohort factors. Consequently, we first review factors potentially affecting cohort health back to 1880 and explore how that history might affect the current and future cohort mortality risks of major chronic diseases. We then examine how those factors affect the age-specific linkage of disability and mortality in three sets of birth cohorts assessed using the 1982, 1984, and 1989 National Long Term Care Surveys and Medicare mortality data collected from 1982 to 1991. We find large changes in both mortality and disability in those cohorts. providing insights into what changes might have occurred and into what future changes might be expected.     

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.