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.     

Does the Hispanic Paradox in U.S. Adult Mortality Extend to Disability?

Studies consistently document a Hispanic paradox in U.S. adult mortality, whereby Hispanics have similar or lower mortality rates than non-Hispanic whites despite lower socioeconomic status. This study extends this line of inquiry to disability, especially among foreign-born Hispanics, since their advantaged mortality seemingly should be paired with health advantages more generally. We also assess whether the paradox extends to U.S.-born Hispanics to evaluate the effect of nativity. We calculate multistate life tables of life expectancy with disability to assess whether racial/ethnic and nativity differences in the length of disability-free life parallel differences in overall life expectancy. Our results document a Hispanic paradox in mortality for foreign-born and U.S.-born Hispanics. However, Hispanics’ low mortality rates are not matched by low disability rates. Their disability rates are substantially higher than those of non-Hispanic whites and generally similar to those of non-Hispanic blacks. The result is a protracted period of disabled life expectancy for Hispanics, both foreign- and U.S.-born.     

中国老年人临终前 生活自理能力的衰退轨迹

本文以老年人为研究对象,以基本生活自理能力(ADL)为测量指标,使用"中国老年健康长寿影响因素跟踪调查"(CLHLS)数据,分析在1998-2014年期间去世的老年人群临终前的生活自理能力的变化轨迹。作者利用组基轨迹模型对男性和女性老年人的生活自理能力变化过程分别进行拟合,发现老年人在临终前的生活自理能力存在显著差异并归纳出三种变化轨迹:生活自理能力完好型、快速发展型和缓慢下降型。研究发现生命历程早期阶段的经历、所处的社会经济状况、年龄效应和队列效应都会对生活自理能力的衰退轨迹产生显著影响。增龄带来的生活自理能力下降使老年人临终前的失能风险及其持续时间增加,而较晚的出生队列在临终前出现长时间失能的可能性较低。在三类轨迹中,自理能力缓慢下降型轨迹受到各种因素的影响最为显著,而该类型的出现概率是影响失能老年人照料负担的主要因素,由此也证明了除去年龄效应与性别差异之外,由社会经济状况、健康行为习惯、生活环境等因素合力产生的健康保护作用将会在失能老年人照料负担增长过程中发挥主导作用。研究还发现老年女性在临终前会面临更高的失能风险和更长时间的失能存活期,其生活自理能力变化过程受到更多因素的影响。     

Aging in the Context of Cohort Evolution and Mortality Selection

This study examines historical patterns of aging through the perspectives of cohort evolution and mortality selection, where the former emphasizes the correlation across cohorts in the age dependence of mortality rates, and the latter emphasizes cohort change in the acceleration of mortality over the life course. In the analysis of historical cohort mortality data, I find support for both perspectives. The rate of demographic aging, or the rate at which mortality accelerates past age 70, is not fixed across cohorts; rather, it is affected by the extent of mortality selection at young and late ages. This causes later cohorts to have higher rates of demographic aging than earlier cohorts. The rate of biological aging, approximating the rate of the senescence process, significantly declined between the mid- and late-nineteenth century birth cohorts and stabilized afterward. Unlike the rate of demographic aging, the rate of biological aging is not affected by mortality selection earlier in the life course but rather by cross-cohort changes in young-age mortality, which cause lower rates of biological aging in old age among later cohorts. These findings enrich theories of cohort evolution and have implications for the study of limits on the human lifespan and evolution of aging.     

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.     

Was there compression of disability for older Americans from 1992 to 2003?

Medical advances and the growth of the elderly population have focused interest on trends in the health of the elderly. Three theories have been advanced to describe these trends: compression of morbidity, expansion of morbidity, and dynamic equilibrium. We applied multistate life table methods to the Medicare Current Beneficiary Survey to estimate active and disabled life expectancy from 1992 to 2003, defining disability as having difficulty with instrumental activities of daily living or activities of daily living. We found increases in active life expectancy past age 65 and decreases in life expectancy with severe disability. These trends are consistent with elements of both the theory of compression of morbidity and the theory of dynamic equilibrium.     

Social inequalities in disability-free life expectancy in the french male population, 1980–1991

We calculate aggregate indicators of population health for occupational groups to gauge changes in health disparities during the 1980-1991 period. The study is based on the experiences of French adult men in three major occupational classes: managers, manual workers, and an intermediary occupational group. Life table models show that managers have longer life expectancy and disability-free life expectancy (DFLE) than manual workers, and a shorter life expectancy with disability. The concurrent increases in life expectancy and DFLE during the period maintained the occupational disparities in health; the years lived with disability, however, declined for all groups, as for the entire French population.     

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。     

Trends in old-age functioning and disability in Japan, 1993-2002

Disability is a burden to individuals and society. Population ageing, combined with the fact that disability is most common among the elderly, has focused attention on trends in old-age disability. This study estimates trends in functioning and disability among Japanese elderly from 1993 to 2002 and contrasts the patterns with those found in the USA. Japan is an especially interesting country because its age structure is relatively old, and it currently has the highest life expectancy in the world despite the fact that just 50 years ago its life expectancy was in the bottom half of all countries. As in the USA, disability rates have fallen. If it were not for the gains in disability between 1993 and 2002, there would have been 1.1 million more disabled elderly in 2002. The reductions were experienced broadly across socio-demographic and economic groups. Increases in education across cohorts are associated with the declines in disability.     

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.     

Gender differences in disability-free life expectancy for selected risk factors and chronic conditions in Canada

This article shows how mortality and morbidity patterns differ for women and men 45 years of age and older. The impact on disability-free life expectancy was calculated for selected risk factors and chronic conditions: low income, low education, abnormal body mass index, lack of physical activity, smoking, cancer, diabetes, and arthritis. For each factor, the expected number of years free of disability was calculated for men and women using multi-state life tables. In terms of disability-free life expectancy, the greatest impacts on affected women were for diabetes (14.1 years), arthritis (8.8 years), and physical inactivity (6.0 years), while for affected men, the greatest impacts were for diabetes (10.5 years), smoking (6.9 years), arthritis (6.5 years), and cancer (6.4 years). The implications of these results are discussed from the perspective of developing programs designed to improve population health status.     

Gender Differences in Disability-Free Life Expectancy for Selected Risk Factors and Chronic Conditions in Canada

SUMMARY

This article shows how mortality and morbidity patterns differ for women and men 45 years of age and older. The impact on disability-free life expectancy was calculated for selected risk factors and chronic conditions: low income, low education, abnormal body mass index, lack of physical activity, smoking, cancer, diabetes, and arthritis. For each factor, the expected number of years free of disability was calculated for men and women using multi-state life tables. In terms of disability-free life expectancy, the greatest impacts on affected women were for diabetes (14.1 years), arthritis (8.8 years), and physical inactivity (6.0 years), while for affected men, the greatest impacts were for diabetes (10.5 years), smoking (6.9 years), arthritis (6.5 years), and cancer (6.4 years). The implications of these results are discussed from the perspective of developing programs designed to improve population health status.     

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.     

The exceptionally high life expectancy of Costa Rican nonagenarians

Robust data from a voter registry show that Costa Rican nonagenarians have an exceptionally high live expectancy. Mortality at age 90 in Costa Rica is at least 14% lower than an average of 13 high-income countries. This advantage increases with age by 1% per year. Males have an additional 12% advantage. Age-90 life expectancy for males is 4.4 years, one-half year more than any other country in the world. These estimates do not use problematic data on reported ages, but ages are computed from birth dates in the Costa Rican birth-registration ledgers. Census data con rm the exceptionally high survival of elderly Costa Ricans, especially males. Comparisons with the United States and Sweden show that the Costa Rican advantage comes mostly from reduced incidence of cardiovascular diseases, coupled with a low prevalence of obesity, as the only available explanatory risk factor. Costa Rican nonagenarians are survivors of cohorts that underwent extremely harsh health conditions when young, and their advantage might be just a heterogeneity in frailty effect that might disappear in more recent cohorts. The availability of reliable estimates for the oldest-old in low- income populations is extremely rare. These results may enlighten the debate over how harsh early-life health conditions affect older-age mortality.     

多维度失能测度指标体系构建及失能分级研究

以ICF理论框架的交互影响理念为依据,从多维度视角构建了失能测度指标体系。首先,通过赋值法,得到多维度下的失能总分,依据得分将其划分为重度失能、偏重度失能、中度失能、轻度失能及健康五种功能状态,构造死亡概率模型及失能状态转移概率模型,结果显示,失能分级标准是可靠的。其次,利用CLHLS数据库2011年及2014年追踪调查数据,通过构造多状态转移概率矩阵,实证测算了多状态失能转移概率;借助第六次全国人口普查数据,估算了中国65岁及以上失能人口规模、各状态维持时间及预期寿命等。结果显示,初始健康的老人三年期转移概率维持在健康的概率最高,其死亡率也最低;而初始状态为重度失能的老人死亡率最高,其维持重度失能及转移到偏重度等失能状态的概率也最高。研究结论表明,直接依据数据的失能状态转移概率测算比建模估计要准确;基于多状态转移概率矩阵评估的失能规模、预期寿命等均比已有分级测度结果可靠性更高。     

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.     

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.     

Projecting the Effect of Changes in Smoking and Obesity on Future Life Expectancy in the United States

We estimate the effects of declining smoking and increasing obesity on mortality in the United States over the period 2010–2040. Data on cohort behavioral histories are integrated into these estimates. Future distributions of body mass indices are projected using transition matrices applied to the initial distribution in 2010. In addition to projections of current obesity, we project distributions of obesity when cohorts are age 25. To these distributions, we apply death rates by current and age-25 obesity status observed in the National Health and Nutrition Examination Survey, 1988–2006. Estimates of the effects of smoking changes are based on observed relations between cohort smoking patterns and cohort death rates from lung cancer. We find that changes in both smoking and obesity are expected to have large effects on U.S. mortality. For males, the reductions in smoking have larger effects than the rise in obesity throughout the projection period. By 2040, male life expectancy at age 40 is expected to have gained 0.83 years from the combined effects. Among women, however, the two sets of effects largely offset one another throughout the projection period, with a small gain of 0.09 years expected by 2040.     

The effect of World War I and the 1918 influenza pandemic on cohort life expectancy of South Australian males born in 1881–1900

Cohort lifetime distribution functions have been estimated for the twenty separate calendar year cohorts of South Australian males born in 1881–1900. A cohort life expectancy at birth was calculated from each of these distribution functions, and a composite assessment made of the reduction in cohort life expectancy at birth due to both World War I 1914–1918 and the 1918 Influenza Pandemic. By partitioning each cohort, the cohort life expectancy at birth of the subgroup that had overseas military service is estimated to be 85 to 90 per cent of the cohort life expectancy at birth of the subgroup that remained in South Australia.     

中国高龄老人生活自理能力多变量多状态生命表分析

基于中国高龄老人健康与长寿纵向调查的 1 998年、 2 0 0 0年和 2 0 0 2年数据和多变量风险回归模型 ,本文用曾—顾—兰德改良多状态生命表方法从性别、城乡居住地、民族、文化程度、经济自立状况、婚姻状况和居住安排角度计算并讨论了中国高龄老人的生活自理预期寿命