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Background Research efforts to measure the concept of healthy ageing have been diverse and limited to specific populations. This diversity limits the potential to compare healthy ageing across countries and/or populations. In this study, we developed a novel measurement scale of healthy ageing using worldwide cohorts. Methods In the Ageing Trajectories of Health-Longitudinal Opportunities and Synergies (ATHLOS) project, data from 16 international cohorts were harmonized. Using ATHLOS data, an item response theory (IRT) model was used to develop a scale with 41 items related to health and functioning. Measurement heterogeneity due to intra-dataset specificities was detected, applying differential item functioning via a logistic regression framework. The model accounted for specificities in model parameters by introducing cohort-specific parameters that rescaled scores to the main scale, using an equating procedure. Final scores were estimated for all individuals and converted to T-scores with a mean of 50 and a standard deviation of 10. Results A common scale was created for 343 915 individuals above 18 years of age from 16 studies. The scale showed solid evidence of concurrent validity regarding various sociodemographic, life and health factors, and convergent validity with healthy life expectancy (r = 0.81) and gross domestic product (r = 0.58). Survival curves showed that the scale could also be predictive of mortality. Conclusions The ATHLOS scale, due to its reliability and global representativeness, has the potential to contribute to worldwide research on healthy ageing.

Unlike other biological populations, the human population is experiencing long-run increases in life expectancy. Those lead to changes in age compositions not typical for other biological populations. Sanderson and Scherbov (2015a) demonstrated that, in many countries in Europe, faster increases in life expectancy lead to faster population aging when measured using the old-age dependency ratio and to slower population aging when measured using the prospective old-age dependency ratio that employs a dynamic old-age threshold. We examine this finding analytically and with simulations. We use an analytic decomposition of changes in mortality schedules into shift and compression processes. We show that shifts and compressions of mortality schedules push the two old-age dependency ratios in opposite directions. Our formal results are supported by simulations that show a positive effect of a mortality shift on the old-age dependency ratio and a negative effect of it on the prospective old-age dependency ratio. The effects are of opposite sign for a mortality compression. Our formal and simulation results generalize observed European trends and suggest that the inverse relationship between life expectancy and prospective old-age dependency would be observed more generally.

1AbstractRecent technological advancements in various domains, such as the biomedical and health, offer a plethora of big data for analysis. Part of this data pool is the experimental studies that record various and several features for each instance. It creates datasets having very high dimensionality with mixed data types, with both numerical and categorical variables. On the other hand, unsupervised learning has shown to be able to assist in high-dimensional data, allowing the discovery of unknown patterns through clustering, visualization, dimensionality reduction, and in some cases, their combination. This work highlights unsupervised learning methodologies for large-scale, high-dimensional data, providing the potential of a unified framework that combines the knowledge retrieved from clustering and visualization. The main purpose is to uncover hidden patterns in a high-dimensional mixed dataset, which we achieve through our application in a complex, real-world dataset. The experimental analysis indicates the existence of notable information exposing the usefulness of the utilized methodological framework for similar high-dimensional and mixed, real-world applications.

The ATHLOS cohort is composed of several harmonized datasets of international cohorts related to health and aging. The healthy aging scale has been constructed based on a selection of particular variables from 16 individual studies. In this paper, we consider a selection of additional variables found in ATHLOS and investigate their utilization for predicting the healthy aging. For this purpose motivated by the dataset’s volume and diversity we focus our attention upon the clustering for prediction scheme, where unsupervised learning is utilized to enhance prediction power, showing the predictive utility of exploiting structure in the data by clustering. We show that imposed computation bottlenecks can be surpassed when using appropriate hierarchical clustering within a clustering for ensemble classification scheme while retaining prediction benefits. We propose a complete methodology which is evaluated against baseline methods and the original concept. The results are very encouraging suggesting further developments in this direction along with applications in tasks with similar characteristics. A strait-forward open source implementation is provided for the R project.

We investigated the relation between alcohol drinking and healthy ageing by means of a validated health status metric, using individual data from the Ageing Trajectories of Health: Longitudinal Opportunities and Synergies (ATHLOS) project. For the purposes of this study, the ATHLOS harmonised dataset, which includes information from individuals aged 65+ in 38 countries, was analysed (n = 135,440). Alcohol drinking was reflected by means of three harmonised variables: alcohol drinking frequency, current and past alcohol drinker. A set of 41 self-reported health items and measured tests were used to generate a specific health metric. In the harmonised dataset, the prevalence of current drinking was 47.5% while of past drinking was 26.5%. In the pooled sample, current alcohol drinking was positively associated with better health status among older adults ((b-coef (95% CI): 1.32(0.45 to 2.19)) and past alcohol drinking was inversely related (b-coef (95% CI): &minus, 0.83 (&minus, 1.51 to &minus, 0.16)) with health status. Often alcohol consumption appeared to be beneficial only for females in all super-regions except Africa, both age group categories (65&ndash, 80 years old and 80+), both age group categories, as well as among all the financial status categories (all p &lt, 0.05). Regional analysis pictured diverse patterns in the association for current and past alcohol drinkers. Our results report the need for specific alcohol intake recommendations among older adults that will help them maintain a better health status throughout the ageing process.

Commonly used measures of population aging categorize adults into those who are “old” and those who are not. How this threshold of the stage of “old age” is determined is crucial for our understanding of population aging. We propose that the old age threshold be determined using an equivalency criterion. People at the old age threshold should be roughly equivalent to one another in relevant characteristics regardless of when and where they lived. The UN publishes two variants of the potential support ratio based on different old age thresholds. One old age threshold is based on a fixed chronological age and the other on a fixed remaining life expectancy. Using historical data on 5-year death rates at the old age threshold as an indicator of one aspect of health, we assess the extent to which the two approaches are consistent with the equivalency criterion. The death rates are derived from all the complete cohort life tables in the Human Mortality Database. We show that the old age threshold based on a fixed remaining life expectancy is consistent with the equivalency criterion, while the old age threshold based on a fixed chronological age is not. The picture of population aging that emerges when measures consistent with the equivalency criterion are used are markedly different from those that result when the equivalency criterion is violated. We recommend that measures of aging that violate the equivalency criterion should only be used in special circumstances where that violation is unimportant.

Significance Global environmental change and discussions about the drivers of international migration lead to renewed interest in population growth and global demographic change. The notion of the demographic dividend was introduced to highlight the benefits of fertility decline, yet, among African leaders, it is also often interpreted as describing the benefits of their youthful populations. Due to its controversial nature, the topic of population was not explicitly included in the Sustainable Development Goals. In this controversial discussion, this paper provides a systematic reassessment about what aspects of demographic change have beneficial consequences for economic growth and sustainable development., The relationship between population changes and economic growth has been debated since Malthus. Initially focusing on population growth, the notion of demographic dividend has shifted the attention to changes in age structures with an assumed window of opportunity that opens when falling birth rates lead to a relatively higher proportion of the working-age population. This has become the dominant paradigm in the field of population and development, and an advocacy tool for highlighting the benefits of family planning and fertility decline. While this view acknowledges that the dividend can only be realized if associated with investments in human capital, its causal trigger is still seen in exogenous fertility decline. In contrast, unified growth theory has established human capital as a trigger of both demographic transition and economic growth. We assess the relative importance of changing age structure and increasing human capital for economic growth for a panel of 165 countries during the time period of 1980–2015. The results show a clear dominance of improving education over age structure and give evidence that the demographic dividend is driven by human capital. Declining youth dependency ratios even show negative impacts on income growth when combined with low education. Based on a multidimensional understanding of demography that considers education in addition to age, and with a view to the additional effects of education on health and general resilience, we conclude that the true demographic dividend is a human capital dividend. Global population policies should thus focus on strengthening the human resource base for sustainable development.

Cohort Profile : The Ageing Trajectories of Health - Longitudinal Opportunities and Synergies (ATHLOS) project

The dependency ratio and its components have had a long and productive life. Here we show that they are no longer the most accurate way of measuring important aspects of population aging. We present ratios related to employment, standardized workers and consumers, health care costs, pension costs, and who is old. These ratios are based either on new data or on new approaches to the study of population aging and are all available on the internet. We compare forecasts of those ratios with forecasts of the dependency ratio, both based on the same UN population data. In all cases, we find that the dependency ratio and the old-age dependency ratio are poor approximations to the more up-to-date ratios. There is little need to use the dependency ratio. More accurate measures are readily available.

Will the population of today's high-income countries continue to age throughout the remainder of the century? We answer this question by combining two methodologies, Bayesian hierarchical probabilistic population forecasting and the use of prospective ages, which are chronological ages adjusted for changes in life expectancy. We distinguish two variants of measures of aging: those that depend on fixed chronological ages and those that use prospective ages. Conventional measures do not, for example, distinguish between 65-year-olds in 2000 and 65- year-olds in 2100. In making forecasts of population aging over long periods of time, ignoring changes in the characteristics of people can lead to misleading results. It is preferable to use measures based on prospective ages in which expected changes in life expectancy are taken into account. We present probabilistic forecasts of population aging that use conventional and prospective measures for high-income countries as a group. The probabilistic forecasts based on conventional measures of aging show that the probability that aging will continue throughout the century is essentially one. In contrast, the probabilistic forecasts based on prospective measures of population aging show that population aging will almost certainly come to end well before the end of the century. Using prospective measures of population aging, we show that aging in high-income countries is likely a transitory phenomenon.

ATHLOS is a 5-year project, funded by the European Union’s Horizon 2020 Research and Innovation Program. Its aim is to achieve a better understanding of healthy ageing, utilising longitudinal data from existing cohort studies. The measure of healthy ageing used within ATHLOS is based on the definition used by the World Health Organization as the ongoing process of developing and maintaining functional ability to enable well-being in older age. The first step of the project was to harmonise 17 community based cohort studies of ageing, covering 38 countries over the world and over 411,000 individuals. In this talk we will discuss the work of the different work packages of the project, including a description of the existing evidence on risk factors of healthy ageing.

In this paper, we use the concept of prospective age to illuminate patterns of aging by gender, and education in Europe. We find that, within countries, the patterns of aging of men and women with high education are comparatively similar to one another, but that the patterns of aging are quite dissimilar for men and women in the low education group. Across countries the patterns of aging become more similar as education levels increase. Thus, when we look across educational strata, we find increasing convergence in the pattern of aging both across countries and by gender within countries. The distinctive patterns of aging in the Eastern European countries are largely associated with the comparatively rapid aging of men in the low education category. If aging patterns by education persist, improvements in the education composition of Eastern European countries would result in the patterns of aging there becoming more similar to those in Western European countries.

The paper is devoted to construction of optimal trajectories in the model, which balances growth trends of investments in capital and labor efficiency. The model is constructed within the framework of classical approaches of the growth theory. It is based on three production factors: capital, educated labor and useful work. GDP level is described by a production function of the Cobb-Douglas type. The utility function of the growth process is given by an integral consumption index discounted on the infinite horizon. The optimal control problem is posed to balance investments in capital and labor efficiency. The problem is solved on the basis of dynamic programming principles. A novelty of the solution consists in constructing nonlinear stabilizers constructed on the feedback principle, which leads the system from any current position to a steady state. Growth and decline trends of the simulated trajectories are studied for all components included in the model.

Probably the most famous demographic riddle of all time is the one that the Sphinx was said to have posed to travellers outside the Greek city of Thebes: ‘Which creature walks on four legs in the morning, two at noon, and three in the evening?’ Unfortunate travellers who could not answer the riddle correctly were immediately devoured. Oedipus, fresh from killing his father, was the first to have got the answer right. The correct answer was ‘humans’. People crawl on their hands and knees as infants, walk on two feet in adulthood, and walk with a cane in old age. We easily recognize the three ages of humans. Humans are born dependent on the care of others. As they grow, their capacities and productivities generally increase, but eventually these reach a peak. After a while, capacities and productivities decline and, eventually, if they are lucky enough to survive, people become elderly, often again requiring transfers and care from others. The human life cycle is the basis of all studies of population ageing, and so we cannot begin to study population ageing without first answering the Sphinx’s riddle. However, answering the Sphinx’s riddle is not enough to get us started on a study of population ageing. We must take two more steps before we begin. First, we must recognize that not all people age at the same rate. As seen in Chapter 5, nowadays more educated people tend to have longer life expectancies than less educated people. Second, we must realize that there is no natural generalization of the Sphinx’s riddle to whole populations. Populations cannot be categorized into the stages of infancy, adulthood, and old age. Indeed, if the Sphinx was reborn today, we might find her sitting near another city and posing an equally perplexing riddle, one especially relevant for our times: ‘What can grow younger as it grows older?’ Answering this riddle correctly is the central challenge of this chapter and the key to understanding population ageing in the twenty-first century.

We merge two methodologies, prospective measures of population aging and probabilistic population forecasts. We compare the speed of change and variability in forecasts of the old age dependency ratio and the prospective old age dependency ratio as well as the same comparison for the median age and the prospective median age. While conventional measures of population aging are computed on the basis of the number of years people have already lived, prospective measures are computed also taking account of the expected number of years they have left to live. Those remaining life expectancies change over time and differ from place to place. We compare the probabilistic distributions of the conventional and prospective measures using examples from China, Germany, Iran, and the United States. The changes over time and the variability of the prospective indicators are smaller than those that are observed in the conventional ones. A wide variety of new results emerge from the combination of methodologies. For example, for Germany, Iran, and the United States the likelihood that the prospective median age of the population in 2098 will be lower than it is today is close to 100 percent.

Conventional measures of population aging, such as proportions over age 65, can present a misleading picture of the aging process by not taking account of changes in people's characteristics beyond their chronological age—for example, changes in remaining life expectancy, health and morbidity, disability rates, and cognitive functioning. The “characteristics approach” set out in this article encompasses multiple features of population aging, yielding new measures that can better inform both demographic analysis and public policy debate. We relate the brief history of this approach, examine its basic mathematical structure, and give empirical examples of the insights it offers, drawing on data from West Germany, Japan, Russia, and the United States.

Many young working age adults in developed countries are failing to thrive in economic, demographic and social terms. Their failure to thrive is a relatively new phenomenon that has not been widely recognized, but it affects young adults in virtually all the more developed countries for which we have relevant data. Young adults nowadays are more often in poverty. They are leaving their parental homes at ever later ages and in some countries the frequency of psychological problems increased. The seriousness of failure to thrive syndrome is reflected in the relationship between relative economic conditions and increased suicide rates. The syndrome is important because young adults are at the prime ages for finding employment, establishing long-run career paths and building an economic basis for founding a family. Developing strategies to arrest the spread of failure to thrive syndrome among young adults, in order to keep them vibrant contributors to our societies, should be a priority for policy makers.

Objective: To provide an example of a new methodology for using multiple characteristics in the study of population aging and to assess its usefulness.Method: Using the English Longitudinal Study of Aging (ELSA), we investigate three characteristics of each person 60 to 85 years old, by level of education, hand-grip strength in 2004 (measured in kilos), chair rise speed in 2004 (measured in rises per minute), and whether the person survived from 2004 to 2012. Because the three characteristics are measured in different units, we convert them into a common metric, called alpha-ages.Results: We find that the average of the alpha-age differentials in the measures of upper body and lower body strength predicts educational differentials in subsequent survival better than either physical measure alone. Discussion: This result demonstrates the benefit of combining characteristics, using alpha-ages to convert incommensurate observations into a common metric.

Objective The aim of the study was to improve the measurement of ageing in Oceania taking into account characteristics of populations and, in particular, changes in life expectancy. Method Using past and projected life tables, we calculated prospective old age dependency ratios (POADRs) to 2060, placing the boundary to old age at a moving point with a fixed remaining life expectancy (RLE) for thirteen territories of Oceania. Results In some territories, POADRs grow less rapidly than old age dependency ratios (OADRs). For example, in Australia and Guam, the OADR is forecast to increase from 0.20 and 0.07 in 1980, respectively, to 0.45 and 0.39 in 2050‐55, while the POADR is forecast to increase from 0.17 and 0.07 to 0.19 and 0.19, respectively, over the same period. Conclusion Policymakers may consider this more rational approach to measurement when considering holistic policy responses to both current issues relating to ageing and mitigating against future challenges.

Most studies of population aging focus on only one characteristic of people: their chronological age. For example, the Old Age Dependency Ratio categorizes people as “old” at age 65, regardless of whether they were living 50 years ago or likely to be living 50 years in the future. But 65-year-olds today generally have higher remaining life expectancies and are healthier than their counterparts in previous generations. Age-specific characteristics vary over time and place. Focusing on only one aspect of the changes entailed in population aging but not on all the others provides a limited picture that is often not appropriate for scientific study or policy analysis.

We present new probabilistic forecasts of the timing of the world's population reaching 8 billion, the world's peak population, and the date at which one-third or more of the world's population would be 60+ years old. The timing of these milestones, as well as the timing of the Day of 7 Billion, is uncertain. We compute that the 60 percent prediction interval for the Day of 8 Billion is between 2024 and 2033. Our figures show that there is around a 60 percent chance that one-third of the world's population would be 60+ years old in 2100. In the UN 2010 medium variant, that proportion never reaches one-third. As in our past forecasts (Lutz et al. 2001, 2008), we find the chance that the world's population will peak in this century to be around 84 percent and the timing of that peak to be highly uncertain. Focal days, like the Day of 7 Billion, play a role in raising public awareness of population issues, but they give a false sense of the certainty of our knowledge. The uncertainty of the timing of demographic milestones is not a constant of nature. Understanding the true extent of our demographic uncertainty can help motivate governments and other agencies to make the investments necessary to reduce it.

The paper is devoted to construction of optimal trajectories in the model which balances growth trends of investments in capital and labor efficiency. The model is constructed within the framework of classical approaches of the growth theory. It is based on three production factors: capital, educated labor and useful work. It is assumed that capital and educated labor are invested endogenously, and useful work is an exogenous flow. The level of GDP is described by an exponential production function of the Cobb-Douglas type. The utility function of the growth process is given by an integral consumption index discounted on the infinite horizon. The optimal control problem is posed to balance investments in capital and labor efficiency. The problem is solved on the basis of dynamic programming principles. Series of Hamiltonian systems are examined including analysis of steady states, properties of trajectories and their growth rates. A novelty of the solution consists in constructing nonlinear stabilizers based on the feedback principle which lead the system from any current position to an equilibrium steady state. Growth and decline trends of the model trajectories are studied for all components of the system and their proportions including: dynamics of GDP, consumption, capital, labor efficiency, investments in capital and labor efficiency.

Using West German panel data constructed from the 1988 and 1994/1995 wave of the DJI Familiensurvey, we analyze the stability and determinants of individuals’ total desired fertility. We find considerable variation of total desired fertility across respondents and across interviews. In particular, up to 50% of individuals report a different total desired fertility across survey waves. Multivariate analysis confirms the importance of background factors including growing up with both parents, having more siblings, and being Catholic for preference formation. Consistent with the idea that life course experiences provide new information regarding the expected costs and benefits of different family sizes, the influence of background factors on total desired fertility is strong early in life and weakens as subsequent life course experiences, including childbearing, take effect. Accounting for unobserved individual heterogeneity, we estimate that an additional child may increase the total desired fertility of women with children by 0.14 children, less than what conventional estimates from cross-sectional data would have suggested.

Population ageing is, in the first instance, a demographic phenomenon; although its consequences go far beyond demography. But the future trends of ageing are not yet known and many of the consequences of ageing will depend on the future speed and extent of ageing. Here we summarize what is already known and what is not yet known about future ageing trends in different parts of the world. We do this through the means of new probabilistic population forecasts. The section ‘New Regional and Global Probabilistic Population Forecasts’ presents the results of those forecasts. They confirm the earlier finding (Lutz et al., Nature, 412(6846), 543–545, 2001a) that it is highly likely that the world’s population growth will come to the end during this century. The following four sections present results for proportions of populations 60+, old age dependency ratios, proportions 80+ and average ages. In the section ‘New Measures of Ageing’, we analyse a new measure of ageing that takes life expectancy changes into account.

During recent years there has been an increasing awareness of the explanatory power of population age structure variables in economic growth regressions. We estimate a new cross-country regression model of the effects of age structure change on economic growth. We use the new model and recent probabilistic demographic forecasts for India to derive the uncertainty of predicted economic growth rates caused by the uncertainty in demographic developments.

In this paper we developed a mathematical model which allows estimating and projecting the effects of prevention and treatment programs on the total population size, HIV-induced deaths, and life expectancies. Considering only the female population we project the changes of the demographic developments and the situation of HIV/AIDS for Botswana up to 2060. Our mathematical model is used to project the female population development considering their age-structure. Treatment programs are included through selecting a price for medication (or giving it for free). Prevention programs consist of two parts: school-based programs which try to change risky behavior and instantaneous prevention (e.g., free condoms) which has only a short-time effect on the infection risk. The main conclusions drawn from our results are that prevention-only programs always yield the fastest decrease in HIV/AIDS prevalence. Adding a medication program reduces the efficiency of the prevention interventions regarding prevalence, but it reduces the number of HIV-induced deaths and increases life expectancies.

An integrated population, economic, and water resource model was developed to address sustainable development questions for Botswana. raditionally, water resources planning models have considered the implications of different assumptions of population and economic growth on the sustainability of existing water resources supply; however, this model extends that capability to consider feedbacks from one model component to another. For example, the model has the unique capability to examine implications of changing water‐related diarrhea incidence on the health of the HIV/AIDS population. Investments in water supply and sanitation or in HIV/AIDS medication impact the health and productivity of the population. The water model uses a physically‐based hydrologic rainfall‐runoff model with surface and groundwater components to produce monthly runoff and groundwater recharge at the watershed scale. Botswana is divided into socioeconomic regions, and the water resources infrastructure is characterized by...

Learning—i.e. the acquisition of new information that leads to changes in our assessment of uncertainty—plays a prominent role in the international climate policy debate. For example, the view that we should postpone actions until we know more continues to be influential. The latest work on learning and climate change includes new theoretical models, better informed simulations of how learning affects the optimal timing of emissions reductions, analyses of how new information could affect the prospects for reaching and maintaining political agreements and for adapting to climate change, and explorations of how learning could lead us astray rather than closer to the truth. Despite the diversity of this new work, a clear consensus on a central point is that the prospect of learning does not support the postponement of emissions reductions today.

This paper presents probabilistic population projections for five regions of Asia (South Asia, Central Asia, China region, Pacific OECD and Pacific Asia) and Asia as a whole. Over this century, Asia will experience very heterogeneous demographic development: Central Asia is expected to almost double in population and South Asia will become by far the world's most populous region, rapidly surpassing the China region. Simultaneously, the Pacific OECD countries are likely to shrink in population size and experience extreme population ageing. The proportion of the population aged 60 and above in these countries (with Japan having the greatest weight) is expected to reach 50 per cent of the total population (with the 95 per cent uncertainty interval ranging from 35 to 61 per cent). The China region will experience a more rapid speed of ageing, with the proportion aged 60 and above expected to increase by a factor of four from 10 per cent in 2000 to 39 per cent in 2100.

ATHLOS aims to identify healthy ageing trajectories, the main determinants, the time when changes in trajectories are produced, and to propose timely interventions to optimise healthy ageing. Moreover, a new definition of ‘old age’ based on many characteristics rather than just chronological age will be used for calculating projections and guide policy recommendations. A harmonised dataset with over 341,000 individuals from existing longitudinal studies of ageing will be created, including information on physical and mental health, life styles, social environment, among others. A single metric of healthy ageing using Item Response Theory will be used. Trajectories will be defined with techniques such as Structural Equation Modelling or Growth Curve Mixture Modelling and cohort effects using Age Period Cohort. Interventions both at the clinical and population level will be designed based on our results. Finally, the impact of those interventions on healthy ageing will be assessed with micro-simulations.

This chapter discusses results of the global survey of experts on the future of low fertility in low-fertility countries. The survey was coordinated by the Wittgenstein Centre for Demography and Global Human Capital as a part of an effort to produce global argument based population projections by age, sex and level of education. First we give an overview of fertility changes in major low-fertility regions. Next we outline main theoretical arguments and review a wide range of factors contributing to fertility change and variation in contemporary low-fertility settings. Subsequently, we present survey results based on 184 assessments of over 170 experts analysing 41 countries with currently low or around replacement fertility and Israel. These experts provided forecasts of period total fertility rate (TFR) in 2030 and 2050, estimated 80% confidence interval of their forecast and assessed the validity and potential impact on fertility of 46 factors. We also compare expert-derived projections of the TFR trends with the forecasts formulated by the UN World Population Prospects in 2010. The survey results in combination with the feedback provided by the invited experts then serve as a basis for formulating a set of projection scenarios for all low fertility countries up until 2050, which are additionally expanded (in a simpler form) through 2200. We present these scenarios and discuss past changes in fertility differences by level of education and their potential future trends in main regions. Presented analyses and projections indicate that a global convergence of fertility to around replacement level, envisioned in the UN projections, appears unlikely. Continuing differentiation combined with partial convergence in fertility towards lower levels is suggested as a more plausible scenario, with East Asia (including China) as well as Russia expected to have sustained very low fertility below 1.5 through 2050. ispartof: World Population and Human Capital in the 21st Century pages:39-146 ispartof: pages:39-146 status: published

Background: Coping with aging populations is a challenge for most developed countries. Supporting non-working adults can create an unsustainable burden on those working. One way of dealing with this is to raise the normal pension age, but this has proven unpopular. A complementary approach is to raise the average labor force participation rate. These policies are generally more politically palatable because they often remove barriers, allowing people who would like to work to do so. Objective: To conceptualize and estimate the trade-off between pension age and labor force participation rate policies. Methods: We project the populations of European countries and apply different levels of labor force participation rates to the projected populations. We introduce the notion of a relative burden, which is the ratio of the fraction of the income of people in the labor market in 2050 that they transfer to adults out of the labor market to the same fraction in 2009. We use this indicator to investigate the trade-offs between changes in normal pension ages and the general level of labor force participation rates. Results: We show that, in most European countries, a difference in policies that results in an increase in average labor force participation rates by an additional one to two percentage points by 2050 can substitute for a one-year increase in the normal pension age. This is important because, in many European countries, without additional increases in labor force participation rates, normal pension ages would have to be raised well above 68 by 2050 to keep the burden on those working manageable. Conclusions: Because of anticipated increases in life expectancy and health at older ages as well as because of financial necessity, some mix of increases in pension ages and in labor force participation rates will be needed. Pension age changes by themselves will not be sufficient.

The effect of changes in age structure on economic growth has been widely studied in the demography and population economics literature. The beneficial effect of changes in age structure after a decrease in fertility has become known as the “demographic dividend.” In this article, we reassess the empirical evidence on the associations among economic growth, changes in age structure, labor force participation, and educational attainment. Using a global panel of countries, we find that after the effect of human capital dynamics is controlled for, no evidence exists that changes in age structure affect labor productivity. Our results imply that improvements in educational attainment are the key to explaining productivity and income growth and that a substantial portion of the demographic dividend is an education dividend.

People in different subgroups age at different rates. Surveys containing biomarkers can be used to assess these subgroup differences. We illustrate this using hand-grip strength to produce an easily interpretable, physical-based measure that allows us to compare characteristic-based ages across educational subgroups in the United States. Hand-grip strength has been shown to be a good predictor of future mortality and morbidity, and therefore a useful indicator of population aging. Data from the Health and Retirement Survey (HRS) were used. Two education subgroups were distinguished, those with less than a high school diploma and those with more education. Regressions on hand-grip strength were run for each sex and race using age and education, their interactions and other covariates as independent variables. Ages of identical mean hand-grip strength across education groups were compared for people in the age range 60 to 80. The hand-grip strength of 65 year old white males with less education was the equivalent to that of 69.6 (68.2, 70.9) year old white men with more education, indicating that the more educated men had aged more slowly. This is a constant characteristic age, as defined in the Sanderson and Scherbov article "The characteristics approach to the measurement of population aging" published 2013 in Population and Development Review. Sixty-five year old white females with less education had the same average hand-grip strength as 69.4 (68.2, 70.7) year old white women with more education. African-American women at ages 60 and 65 with more education also aged more slowly than their less educated counterparts. African American men with more education aged at about the same rate as those with less education. This paper expands the toolkit of those interested in population aging by showing how survey data can be used to measure the differential extent of aging across subpopulations.

Increases in median ages, the most commonly used measure of population ageing, are rapid in today's wealthier countries, and population ageing is widely considered to be a significant challenge to the well-being of citizens there. Conventional measures of age count years since birth; however, as lives lengthen, we need to think of age also in terms of years left until death or in proportion to the expanding lifespan. Here we propose a new measure of ageing: the median age of the population standardized for expected remaining years of life. We show, using historical data and forecasts for Germany, Japan and the United States, that although these populations will be growing older, as measured by their median ages, they will probably experience periods in which they grow younger, as measured by their standardized median ages. Furthermore, we provide forecasts for these countries of the old-age dependency ratio rescaled for increases in life expectancy at birth. These ratios are forecasted to change much less than their unscaled counterparts, and also exhibit periods when the population is effectively growing younger.