THE STATE OF DEMOGRAPHIC CHANGE GLOBALLY

Significant gains in longevity were achieved beginning in the 20th century in part as a result of advances in public health, including infrastructure (sanitation and water systems), food quality and safety, hygiene, immunizations and antibiotics, prenatal and maternity care, and medical care (Partridge et al., 2018). Increased physical security through protection from violence and conflict has also contributed to longer lives. In some countries, longevity has been driven by improved labor conditions and higher incomes. While these advances initially meant that more people had the opportunity to live longer, these gains in longevity have not necessarily come with similar gains in years lived in good health. On average globally, people now live longer than they did in 2000, but an increased number of people live longer with chronic conditions¹ and declining function and well-being, resulting in what some call a “decompression of morbidity” (Rowe and Berkman, 2022).

The benefits of increased longevity have not been equally shared, with disadvantaged populations experiencing neither the longevity nor the health gains of more privileged populations within countries, and significant differences in longevity from country to country (Permanyer and Scholl, 2019). Much of the evidence about trends in longevity presented throughout this report predates the onset of the COVID-19 pandemic, and evidence of its impact continues to emerge. A recent study of 37 upper-middle- and high-income countries showed increased life expectancy in only three countries, no change in two countries, and decreased life expectancy in the remaining 32 countries (Islam et al., 2021). Across the countries, 28.1 million more years of life were lost than expected. Future trends in life expectancy are uncertain, and many trends described in this report (e.g., life expectancy, health status, employment trends) are in flux as a result of COVID-19.

Today the global population is projected to age rapidly as the result of two distinct trends: the rise in longevity and falling birth rates. Nearly 20 percent of the global population is estimated to be over age 65 by 2050, double the percentage in 2019, while the population aged 15–65 is predicted to rise by 20 percent. The contours of demographic change will be unique to each country and population around the world. Figures 1-1 through 1-3 show the dramatic rise in the population aged 65 and older as a percentage of the population in 1950, 2000, and 2050 (projected) in the world, Singapore, and Nigeria (note that the scales of the figures differ because of the dramatic differences in total population) (UN DESA, 2019a). The models show that the population of older people is increasing, but the patterns of population growth and aging over time differ, as indicated by the horizontal and vertical shapes of the graphs, respectively.² Typically, the wealthiest nations are furthest along in this demographic transition and have the highest proportion of older people, but the number of older people living in low- and middle-income countries is higher than the number in high-income countries. While many countries, such as Nigeria, currently have a large younger population, this large young cohort is projected to become a large old cohort. Therefore, an aging society is a reality for countries across income levels, with the only question being when they will become an aging society.

FIGURE 1-1

World population pyramid: 1950, 2020, and 2050. NOTE: Blue = male population; yellow = female population. SOURCE: UN DESA, 2019a. This work is licensed under a Creative Commons Attribution 3.0 IGO License (https://creativecommons.org/licenses/by/3.0/igo). (more...)

FIGURE 1-3

Nigeria population pyramid: 1950, 2020, and 2050. NOTE: Green = male population; purple = female population. SOURCE: UN DESA, 2019a. This work is licensed under a Creative Commons Attribution 3.0 IGO License (https://creativecommons.org/licenses/by/3.0/igo). (more...)

Differences in age structures create different challenges among countries in the near term, such as countries in sub-Saharan Africa that face high rates of youth unemployment while many high-income countries face a shrinking workforce. A country's challenges will drive how it allocates resources. Moreover, low- and middle-income countries will have few resources available to develop the systems needed for healthy longevity, such as health care and long-term care.

Nonetheless, to respond to this demographic shift, it will be imperative for countries to take steps, however incremental, to redesign society for longer lives, including how older people can engage with and contribute to family, community, and society.

In recent decades, the average household size in most countries has declined, and fewer people are living in multigenerational households, although this trend may have changed during the COVID-19 pandemic. In addition to these rapid demographic shifts, populations are changing, and demography will be influenced by climate change and rapid investments in information technology. Countries are also facing socioeconomic changes that are altering family structures and living arrangements, potentially putting older people at risk. Changes in fertility levels, marriage patterns, educational attainment, urbanization, migration, and economic development are all influencing the lives of older people (UN DESA, 2021). Living alone or with a spouse and no other family members is widely valued in many high-income countries, but it is less often valued in low- and middle-income countries. In low- and middle-income countries, those not living within a larger family unit are likely to experience worse health outcomes, higher rates of poverty, and worse quality of life (Kamiya and Hertog, 2020). These changes in family structure and living arrangements also have important and potentially detrimental ramifications for intergenerational caregiving, financial security, and social connection. In Africa and Latin America, for example, older adults and grandparents are often the caregivers for children orphaned by HIV/AIDS (He et al., 2020; UN DESA, 2019b), and there is a disconnect between older adults' knowledge of modern medicine and basic pediatric health needs, such as vaccinations. Additionally, tension exists in some countries between older and younger people, the latter believing that older people receive a disproportionate share of jobs and government benefits (see Appendix C).

FIGURE 1-2

Singapore population pyramid: 1950, 2020, and 2050. NOTE: Red = male population; dark blue = female population. SOURCE: UN DESA, 2019a. This work is licensed under a Creative Commons Attribution 3.0 IGO License (https://creativecommons.org/licenses/by/3.0/igo). (more...)

THE SCIENCE OF HEALTHY LONGEVITY

AGING MYTHS AND AGEISM

Steady declines in health, physical and cognitive function, and well-being associated with aging have long been viewed as an inevitable part of life (Sierra, 2016). Many people in the later stages of life experience prolonged periods of debilitating chronic conditions, functional decline, and diminished well-being (Diehl et al., 2020). These declines have long led to perceptions that older people as a group are inevitably dependent and a drain on society, despite the fact that many live without functional limitations (Achenbaum, 2021). In numerous countries in North and South America, a majority of adults over age 65 live without serious physical or cognitive limitations, with many living independently in the community (Fausset et al., 2011; Houser et al., 2009; Rofman and Apella, 2020). Furthermore, aging brings on average more positive emotional well-being, emotional stability, and emotional complexity; an array of mature capabilities; and greater prosocial motivation (Carstensen et al., 2011).

WHO defines ageism as “when age is used to categorize and divide people in ways that lead to harm, disadvantage and injustice and erode solidarity across generations” (WHO, 2021a, p. xv). Ageism affects people of all ages and is socially accepted in a way that other forms of prejudice are not. Nonetheless, because ageism leads to discrimination and unequal treatment, “ageism shortens lives; leads to poorer physical health and worse health behaviours; impedes recovery from disability; results in poorer mental health; exacerbates social isolation and loneliness; and reduces quality of life” (WHO, 2021a, p. 48).

The COVID-19 pandemic brought to the surface deep-seated ageism in some countries, such as the United States, manifesting in intergenerational resentment toward older people.⁴ This resentment can be interpreted as reflecting younger people's views of older people as a drain on the economy and government finances (see Appendix B). Even within the health care system, chronological age was used to determine some people's access to a mechanical ventilator, despite arguments that use of chronological age to allocate scarce resources is not ethically justifiable (Jecker and Pearlman, 1989; Joebges and Biller-Andorno, 2020; Montero-Odasso et al., 2020).

Ageism often manifests in the form of myths (see Box 1-1). While science has disproven many myths about aging that form the basis of age-based prejudice and stereotypes, the health care systems, socioeconomic structures, and policies designed around those myths have not changed. If ageism is overcome at the same time that health and function in older people improve, the inevitable shifts in population age structure and changing family structures can become drivers of a thriving society with the many positive characteristics described in this report.

BOX 1-1

Myths About Aging.

REFRAMING THE CHALLENGE OF AGING SOCIETIES

Healthy longevity reframes the false assumptions that aging societies reduce workforce productivity and increase burdens on families and that older people disproportionately consume resources. A clear-eyed, evidence-informed view of the capabilities and vulnerabilities of older people points to the very real potential of aging societies to be, on balance, positive. It is important to recognize the substantial socioeconomic gradients that drive vast differences between advantaged and disadvantaged populations within and across countries. Together these observations suggest that long-lived populations are not an inherent problem for societies; rather, the problem for societies is the barriers that systematically prevent people from reaching their later years with the good health needed to thrive and contribute to family and society. To the extent that healthy longevity is accelerated on a global scale, a social resource can be developed that has never existed in human history—age-diverse societies that build on the complementarity of skills and qualities typical of both younger and older people. An evidence-based reframing of the potential of longevity suggests the need to move away from an exclusive focus on “coping with aging populations” toward removing existing barriers so the global community can age successfully and reap the economic and societal benefits of healthy older people. Accordingly, the focus of this report is on understanding how societies can create environments that provide support across the life course for people who need it while maximizing the contributions and capacities of individuals of older age.

THE COMPLEX SYSTEM OF GLOBAL HEALTHY LONGEVITY

Based on the evidence provided in this report, the commission argues that healthy longevity, or the lack thereof, is the result of the interactions of complex systems. To achieve the vision for healthy longevity described in the next chapter, multiple systems within society will need to be activated, transformed, and coordinated because healthy longevity is about all aspects of life. Advances in medicine have lengthened human life by preventing and treating diseases and developing systems to better control for the multitude of factors that influence human health. As discussed throughout this report, however, a person's health is determined by social context, environment, and public health as experienced throughout life, in addition to biology and health care. Socioeconomic determinants of health, such as income security, education, and work, are critical drivers of healthy longevity.

While people are living longer, they are experiencing longer periods in poor health. No country or society has implemented a system that maximizes the potential of healthy older people and has achieved healthy longevity across the population. Too often, the systems influencing healthy longevity operate in isolation from one another. Diverse systems such as public health, income security, and a healthy environment are generally not connected by a goal of achieving healthy longevity for populations. A paradigm shift is needed to capitalize on opportunities lost when societies fail to maximize contributions from all people.

In making widespread change addressing all of these elements of a complex system, effort must be directed to reducing current and preventing further disparities between, within, and across countries. In many low-income countries, making breakthrough scientific advances in aging widely available to all citizens may not be achievable while also attending to, for example, gains in providing primary education. In middle- and high-income countries, trade-offs will also need to be considered in determining how best to achieve healthy longevity for all people. With more than half of the World Economic Forum's top 10 global risks in 2022 focused on environmental risks, resources are limited for making these broad systems changes (WEF, 2022). Nevertheless, the commission believes that the overall condition of a complex social, economic, and environmental system requires multipronged solutions to be devised and implemented by communities at the local level while being coordinated at the national and regional levels. By aligning efforts, activating all parts of society, and intentionally focusing on the interactions and relationships among these systems, the commission believes progress can be made toward developing healthier, longer lives for people around the world.

THE NATIONAL ACADEMY OF MEDICINE'S HEALTHY LONGEVITY GLOBAL GRAND CHALLENGE: CHARGE AND APPROACH

The National Academy of Medicine's (NAM's) Healthy Longevity Global Grand Challenge is a worldwide movement initiated in 2018 to improve physical, mental, and social well-being for people as they age. The aims of the initiative are to (1) comprehensively address the challenges and opportunities presented by global population aging; (2) catalyze breakthrough ideas and research that will extend the human health span; (3) generate transformative and scalable innovations worldwide; and (4) build a broad ecosystem of support by enabling scientists, engineers, innovators, entrepreneurs, health leaders, policy makers, and the public to work together to achieve the promise of healthy longevity. Indeed, the commission approached the report with the goal of changing the perspectives of leaders across the public and private sectors to make an evidence-based case for achieving healthy longevity. Primary audiences for this report include leaders of health systems, employers, unions, nongovernmental organizations, faith institutions, and the news media. The report may also have applications for families and individuals seeking to learn more about the possibilities of healthy longevity and the opportunities to catalyze change in their communities.

In choosing to focus on healthy longevity, NAM recognized the convergence of multiple factors that have placed society on a precipice between an optimistic future of healthy longevity and avoidable disability and social challenges. These factors include the following:

• rising numbers of older adults globally compared with other age segments within the population, with rapidly rising numbers of older adults in many countries;
• rising rates of age-related chronic illnesses that, absent changes from the current trajectory, will increasingly burden individuals, families, and governments with rising health care costs;
• loss of human value, well-being, function, and dignity to disability caused by chronic illness, frailty, and cognitive decline;
• shifting family structures, dynamics, and norms within contexts of globalization, economic development, and crises and trends in urbanization and migration;
• a growing recognition that the current system of retirement, for those who are able to retire, is suboptimal for many individuals, organizations and institutions, and society as a whole;
• increasing social fraying, in some contexts, between younger and older generations;
• identification of social determinants of healthy longevity and the role of the built environment;
• evidence of the significant impacts of climate change and pollution on people across the life course; and
• a growing body of evidence demonstrating how to promote healthy longevity.

This report is the product of one of the two parts of the Grand Challenge. An international, independent, and multidisciplinary commission was charged with developing a comprehensive report assessing the challenges and opportunities presented by population aging and making evidence-based recommendations for how the challenges can be translated into opportunities for societies globally (see Box 1-2). The second part of the Grand Challenge is the Healthy Longevity Global Competition. Through inducement prizes and awards, the initiative catalyzes transformative innovation and informs policies and priorities to advance healthy aging and longevity globally. The Global Competition is an ongoing separate activity from this report and is not discussed here in detail.

BOX 1-2

Statement of Task.

Where possible, the commission coordinated with other related global initiatives to achieve an integrated and synergistic effort. With equity as a central focus, the commission considered how evidence should inform policy and practice, innovation, financing, and monitoring metrics with respect to healthy longevity. The commission approached its work by collecting evidence across three domains: (1) social, behavioral, and environmental enablers; (2) health care systems and public health; and (3) science and technology. In three workshops, each dedicated to one of those three domains, the commission convened thought leaders from biological and behavioral sciences, medicine, health care, public health, engineering, technology, economics, and policy to identify the essential priorities and directions for improving health, productivity, and quality of life for older adults worldwide.

The commission also identified the need for consultations in two areas. First, it sought information about the state of aging from experts in global regions not adequately represented among the commission members, such as roles for older adults, filial piety, employment and retirement, and intergenerational cohesion, with an emphasis on low- and middle-income countries. Second, the commission sought information from experts in economics about how the economy and government spending affect healthy longevity and, conversely, how healthy longevity has the potential to affect the economy and government spending. Commissioners and NAM staff identified and invited experts to provide responses to targeted questions either in writing or during a brief discussion with staff (see Appendix C).

The commission used a “future-back vision” approach⁵ to imagine a world in 2050 in which healthy longevity is a reality. This approach entails first an unrestrained imagining of what the future could look like based on the evidence, and then articulation of the steps needed to reach that vision. The future-back approach contrasts with the more common “present-forward” approach, whereby imagination is limited to evolution of the current state. Given that the society and systems of today were designed for lives much shorter than the current life span, the commission recognized the need for redesign to look across systems and reflect the vision of a future unconstrained by the status quo. Once imagined, the future-back vision is deconstructed to provide a roadmap of targets starting from the present and working toward the ideal future. Planning entails considering current limitations and barriers; identifying priority areas; and developing strategies, policies for implementation, and measures of success. By detailing the new future and specific targets for attaining it, including actionable goals, the approach ensures a continued focus on the end goal—the realized vision of a future of healthy longevity.

The commission met numerous times over the course of the study and collected and assessed research from a range of fields relevant to healthy longevity. This report also builds on and is consistent with previous reports of WHO, including Decade of Healthy Ageing Baseline Report (2021c); the United Nations, including Political Declaration and Madrid International Plan of Action on Ageing (2002); and the National Academies, such as Social Isolation and Loneliness in Older Adults: Opportunities for the Health Care System (2020), Aging and Disability: Beyond Stereotypes to Inclusion: Proceedings of a Workshop (2018), Nutrition Across the Lifespan for Healthy Aging: Proceedings of a Workshop (2017a), Communities in Action: Pathways to Health Equity (2017b), Understanding Pathways to Successful Aging: How Social and Behavioral Factors Affect Health at Older Ages: Workshop in Brief (2015), and Retooling for an Aging America: Building the Health Care Workforce (IOM, 2008), among others.

A HEALTHY LONGEVITY ROADMAP

Currently, the world is unprepared to address the challenges of rapid global aging and has not been able to translate this disruptive change into opportunity (He et al., 2016). Countries with the largest proportion of older people are experiencing many undesirable outcomes related to aging, including negative economic impacts, with increasing numbers of people leaving the workforce and rapidly rising health and social care costs, as well as increases in social isolation, loneliness, and suicide rates (Bloom et al., 2015; Holt-Lunstad et al., 2010; NASEM, 2020). Many of these negative outcomes will impact all countries, even those with a slower aging trajectory and younger populations. Specifically, the rise in chronic conditions, which develop about a decade earlier in low-income countries than high-income countries (see Chapter 6), will contribute to increased health and social care costs in all countries. If not addressed, avoidable or modifiable age-related decline that impairs health, function, and well-being will continue to burden older people and their families. Younger people may live with fear and trepidation with respect to their own aging. Societies will bear avoidable care costs, and humanity will lose the benefits that could have been realized from the contributions of older people with healthy longevity.

Demographic aging can be translated into a better world for all with thoughtful, strategic change. Science can provide direction for action that societies around the world can take to seize the opportunity to prepare for a future in which healthy longevity is realized for all people. This report is grounded in the belief that healthy longevity can initiate and perpetuate the virtuous cycle depicted in Figure 1-4. Healthy longevity enables health and productive engagement throughout the life course; the benefits of healthy longevity build social, human, and economic capital; these expanded resources allow governments to ensure that healthy longevity is sustained by supporting enablers that stem from the health system, work, volunteering, socioeconomic conditions, and the physical environment; and the cycle repeats. At the center of this cycle is a new social compact driven by equity and social cohesion.

FIGURE 1-4

The virtuous cycle of healthy longevity.

REPORT STRUCTURE

This report, the culmination of efforts summarized above, describes the significant untapped human potential of older people within society, as well as the benefits that would accrue to individuals and society if this potential were to be unleashed. It provides evidence-based recommendations for how countries can pursue an optimistic vision of healthy longevity for individuals and societies, a vision whereby prolonged periods of functional and cognitive decline as people age are no longer viewed as inevitable. This is also a vision of a cohesive, productive society that supports the aspirations of people in the first and second halves of life. Public- and private-sector organizations and institutions can use the findings, conclusions, and recommendations in this report to shape a future of healthy longevity by 2050 that is appropriate to a variety of cultural norms, stages of development, maturity of care systems, and resources.

The commission emphasizes cross-cutting themes across all chapters of the report. These themes include equity and nondiscrimination, lessons learned from the COVID-19 pandemic, and science and technology as enablers of healthy longevity. The importance of a life-course approach to healthy longevity is a central recurring theme; it is impossible to separate healthy longevity in older adults from what has affected them in younger years.

Following this introduction, the report is organized into six chapters. Chapter 2 presents the commission's vision for healthy longevity in 2050. It describes an aspirational society in which healthy longevity has been achieved, based on the elements depicted in Figure 1-4. Chapter 3 describes the longevity dividend that would result from longer, healthier lives and the “capital”—human, financial, and social—that can result from healthy longevity, as seen in the bottom-left portion of Figure 1-4. Social enablers, physical environment enablers, and health systems—the enablers in the bottom-right portion of Figure 1-4—are discussed in Chapters 4 through 6, respectively. Finally, Chapter 7 presents the commission's roadmap for achieving its vision of healthy longevity.

This report is offered as a roadmap for all countries to begin a process of engagement and shared learning across all sectors and all actors in the global community as they develop plans and programs to ensure healthy longevity. The report necessarily relies heavily on evidence from and experience of high-income countries. The majority of the evidence on healthy longevity was developed within and for high-income countries. The experience of addressing rapid aging, to date, has happened primarily in high-income countries. The commission selected targets that, with few exceptions, are relevant to all countries.

REFERENCES

• AAMC (Association of American Medical Colleges). Geriatric medicine. 2021. [February 23, 2021]. https://www​.aamc.org​/cim/explore-options​/specialty-profiles/geriatric-medicine-0 .
• Achenbaum W. Dr. Robert Butler's legacy in defining and fighting ageism. University of Toronto Quarterly. 2021;90(2):80–95.
• Backes-Gellner U, Keil U, Baumert J. More years, more life: Recommendations of the Joint Academy Initiative on Aging. Halle, Germany: Deutsche Akademie der Naturforscher Leopoldina; 2010.
• Baltes PB, Staudinger UM. The search for a psychology of wisdom. Current Directions in Psychological Science. 1993;2(3):75–81.
• Bangen KJ, Meeks TW, Jeste DV. Defining and assessing wisdom: A review of the literature. The American Journal of Geriatric Psychiatry. 2013;21(12):1254–1266. [PMC free article: PMC3896261] [PubMed: 23597933]
• Barzilai N, Cuervo AM, Austad S. Aging as a biological target for prevention and therapy. Journal of the American Medical Association. 2018;320(13):1321–1322. [PubMed: 30242337]
• Birren JE. Cambridge, MA: Academic Press; Encyclopedia of gerontology: Age, aging, and the aged. 1996;1-2
• Bloom DE, Chatterji S, Kowal P, Lloyd-Sherlock P, McKee M, Rechel B, Rosenberg L, Smith JP. Macroeconomic implications of population ageing and selected policy responses. The Lancet. 2015;385(9968):649–657. [PMC free article: PMC4469267] [PubMed: 25468167]
• Burr DA, Castrellon JJ, Zald DH, Samanez-Larkin GR. Emotion dynamics across adulthood in everyday life: Older adults are more emotionally stable and better at regulating desires. Emotion. 2020;21:453–464. [PMC free article: PMC8267403] [PubMed: 32191090]
• Carstensen LL, Turan B, Scheibe S, Ram N, Ersner-Hershfield H, Samanez-Larkin GR, Brooks KP, Nesselroade JR. Emotional experience improves with age: Evidence based on over 10 years of experience sampling. Psychology and Aging. 2011;26(1):21. [PMC free article: PMC3332527] [PubMed: 20973600]
• Chen C, Maung K, Rowe JW, Antonucci T, Berkman L, Börsch-Supan A, Carstensen L, Goldman DP, Fried L, Furstenberg F. Gender differences in countries' adaptation to societal ageing: An international cross-sectional comparison. The Lancet Healthy Longevity. 2021;2(8):e460–e469. [PubMed: 36098150]
• Clark CN, Warren JD. A hypnic hypothesis of Alzheimer's disease. Neurodegenerative Diseases. 2013;12(4):165–176. [PMC free article: PMC3884167] [PubMed: 23635607]
• Coughlin J. International workshop on science and technology for healthy longevity day 1. 2021. [April 25, 2022]. Presentation at the Global Roadmap for Healthy Longevity: Science and Technology Workshop. https://nam​.edu/event​/international-workshop-on-science-technology-for-healthy-longevity-day-1.
• Diehl M, Smyer MA, Mehrotra CM. Optimizing aging: A call for a new narrative. American Psychologist Journal. 2020;75(4):577–589. [PMC free article: PMC7213015] [PubMed: 32378951]
• Dreborg KH. Essence of backcasting. Futures. 1996;28(9):813–828.
• Fausset CB, Kelly AJ, Rogers WA, Fisk AD. Challenges to aging in place: Understanding home maintenance difficulties. Journal of Housing for the Elderly. 2011;25(2):125–141. [PMC free article: PMC3209521] [PubMed: 22072843]
• Grossmann I, Karasawa M, Izumi S, Na J, Varnum ME, Kitayama S, Nisbett RE. Aging and wisdom: Culture matters. Psychological Science. 2012;23(10):1059–1066. [PubMed: 22933459]
• He W, Goodkind D, Kowal PR. An aging world: 2015. Washington, DC: U.S. Census Bureau; 2016.
• He W, Aboderin I, Adjaye-Gbewonyo D. Africa aging: 2020. Washington, DC: U.S. Government Printing Office; 2020.
• Herrmann M, Pusceddu I, März W, Herrmann W. Telomere biology and age-related diseases. Clinical Chemistry and Laboratory Medicine. 2018;56(8):1210–1222. [PubMed: 29494336]
• Holmberg J, Robert KH. Backcasting—A framework for strategic planning. International Journal of Sustainable Development & World Ecology. 2011;7(4):291–308.
• Holt-Lunstad J, Smith TB, Layton JB. Social relationships and mortality risk: A meta-analytic review. PLoS Medicine. 2010;7(7):e1000316. [PMC free article: PMC2910600] [PubMed: 20668659]
• Houser AN, Fox-Grage W, Gibson MJS. Across the states: Profiles of long-term care and independent living. Washington, DC: AARP Public Policy Institute; 2009.
• Inouye SK, Studenski S, Tinetti ME, Kuchel GA. Geriatric syndromes: Clinical, research, and policy implications of a core geriatric concept. Journal of the American Geriatrics Society. 2007;55(5):780–791. [PMC free article: PMC2409147] [PubMed: 17493201]
• IOM (Institute of Medicine). Retooling for an aging America: Building the health care workforce. Washington, DC: The National Academies Press; 2008. https://doi​.org/10.17226/12089 . [PubMed: 25009893]
• Islam N, Jdanov DA, Shkolnikov VM, Khunti K, Kawachi I, White M, Lewington S, Lacey B. Effects of COVID-19 pandemic on life expectancy and premature mortality in 2020: Time series analysis in 37 countries. BMJ. 2021;375:e066768. [PMC free article: PMC8564739] [PubMed: 34732390]
• Jecker NS, Pearlman RA. Ethical constraints on rationing medical care by age. Journal of the American Geriatrics Society. 1989;37:1067–1075. [PubMed: 2809055]
• Joebges S, Biller-Andorno N. Ethics guidelines on COVID-19 triage—An emerging international consensus. Critical Care. 2020;24(201) [PMC free article: PMC7202791] [PubMed: 32375855]
• Kaeberlein M. Translational geroscience: A new paradigm for 21st century medicine. Translational Medicine of Aging. 2017;1:1–4. [PMC free article: PMC7098696] [PubMed: 32219192]
• Kamiya Y, Hertog S. Measuring household and living arrangements of older persons around the world: The United Nations database on the households and living arrangements of older persons. Population Division, Department of Economic and Social Affairs; New York: 2020. (Technical paper no. 3). United Nations.
• Kenyon C, Chang J, Gensch E, Rudner A, Tabtiang R. A C. elegans mutant that lives twice as long as wild type. Nature. 1993;366(6454):461–464. [PubMed: 8247153]
• Langa KM, Larson EB, Crimmins EM, Faul JD, Levine DA, Kabeto MU, Weir DR. A comparison of the prevalence of dementia in the United States in 2000 and 2012. JAMA Internal Medicine. 2017;177(1):51–58. [PMC free article: PMC5195883] [PubMed: 27893041]
• Lovins A. Foreign Affairs. 1974. [February 23, 2021]. Energy strategy: The road not taken? https://www​.foreignaffairs​.com/articles/united-states​/1976-10-01​/energy-strategy-road-not-taken .
• Montero-Odasso M, Hogan DB, Lam R, Madden K, MacKnight C, Molnar F, Rock-wood K. Age alone is not adequate to determine health-care resource allocation during the COVID-19 pandemic. Canadian Geriatrics Journal. 2020;23(1):152–154. https://doi​.org/10.5770/cgj.23.452 . [PMC free article: PMC7279701] [PubMed: 32550953]
• Muzet A. Environmental noise, sleep and health. Sleep Medicine Reviews. 2007;11(2):135–142. [PubMed: 17317241]
• NASEM (National Academies of Sciences, Engineering, and Medicine). Understanding pathways to successful aging: How social and behavioral factors affect health at older ages: Workshop in brief. Washington, DC: The National Academies Press; 2015. https://doi​.org/10.17226/21815 .
• NASEM. Nutrition across the lifespan for healthy aging: Proceedings of a workshop. Washington, DC: The National Academies Press; 2017a. https://doi​.org/10.17226/24735 . [PubMed: 28530787]
• NASEM. Communities in action: Pathways to health equity. Washington, DC: The National Academies Press; 2017b. https://doi​.org/10.17226/24624 . [PubMed: 28418632]
• NASEM. Aging and disability: Beyond stereotypes to inclusion: Proceedings of a workshop. Washington, DC: The National Academies Press; 2018. https://doi​.org/10.17226/25029 . [PubMed: 29989764]
• NASEM. Social isolation and loneliness in older adults: Opportunities for the health care system. Washington, DC: The National Academies Press; 2020. https://doi​.org/10.17226/25663 . [PubMed: 32510896]
• Niccoli T, Partridge L. Ageing as a risk factor for disease. Current Biology. 2012;22(17):R741–R752. [PubMed: 22975005]
• Partridge L, Deelen J, Slagboom PE. Facing up to the global challenges of ageing. Nature. 2018;561(7721):45–56. [PubMed: 30185958]
• Permanyer I, Scholl N. Global trends in lifespan inequality: 1950-2015. PloS One. 2019;14(5):e0215742. [PMC free article: PMC6497240] [PubMed: 31048892]
• Robinson J. Energy backcasting: A proposed method of policy analysis. Energy Policy. 1982;10(4):337–344.
• Roehr S, Pabst A, Luck T, Riedel-Heller SG. Is dementia incidence declining in high-income countries? A systematic review and meta-analysis. Clinical Epidemiology. 2018;10:1233. [PMC free article: PMC6149863] [PubMed: 30271219]
• Rofman R, Apella I. When we're sixty-four: Opportunities and challenges for public policies in a population-aging context in Latin America. Washington, DC: World Bank; 2020.
• Rowe JW, Berkman L. Decompression of morbidity and the workforce. Nature Aging. 2022;2(1):3–4.
• Schou TM, Joca S, Wegener G, Bay-Richter C. Psychiatric and neuropsychiatric sequelae of COVID-19—A systematic review. Brain, Behavior, and Immunity. 2021;97:328–348. [PMC free article: PMC8363196] [PubMed: 34339806]
• Sierra F. The emergence of geroscience as an interdisciplinary approach to the enhancement of health span and life span. Cold Spring Harbor Perspectives in Medicine. 2016;6(4):a025163. [PMC free article: PMC4817738] [PubMed: 26931460]
• St. Sauver JL, Boyd CM, Grossardt BR, Bobo WV, Rutten LJF, Roger VL, Ebbert JO, Therneau TM, Yawn BP, Rocca WA. Risk of developing multimorbidity across all ages in an historical cohort study: Differences by sex and ethnicity. BMJ Open. 2015;5(2):e006413. [PMC free article: PMC4322195] [PubMed: 25649210]
• Stone AA, Schwartz JE, Broderick JE, Deaton A. A snapshot of the age distribution of psychological well-being in the United States. Proceedings of the National Academy of Sciences. 2010;107(22):9985–9990. [PMC free article: PMC2890490] [PubMed: 20479218]
• Sun R, Sauter D. Sustained stress reduces the age advantages in emotional experience of older adults: Commentary on Carstensen et al. (2020). Psychological Science. 2021;32(12):2035–2041. [PubMed: 34788164]
• Tucker-Drob EM. Cognitive aging and dementia: A life-span perspective. Annual Review of Developmental Psychology. 2019;1:177–196. [PMC free article: PMC8153102] [PubMed: 34046638]
• UN (United Nations). Political declaration and Madrid international plan of action on ageing. 2002. [May 13, 2022]. https://www​.un.org/esa​/socdev/documents/ageing​/MIPAA/political-declaration-en​.pdf .
• UN DESA (Department of Economic and Social Affairs). World population prospects. 2019a. [February 23, 2021]. https://population​.un​.org/wpp/Graphs/DemographicProfiles​/Pyramid/900 .
• UN DESA. Population Facts 2019. 2. 2019b. [April 25, 2022]. Living arrangements of older people around the world. https://www​.un.org/en​/development/desa/population​/publications​/pdf/popfacts/PopFacts_2019-2.pdf .
• UN DESA. Global population growth and sustainable development. New York: United Nations Department of Economic and Social Affairs; 2021.
• Verdin E. Science and technology for healthy longevity: A workshop for the global roadmap for healthy aging. 2021. [April 25, 2022]. Presented at the International Workshop on Science and Technology for Healthy Longevity day 1. https://nam​.edu/event​/international-workshop-on-science-technology-for-healthy-longevity-day-1.
• Walsh S, Govia I, Wallace L, Richard E, Peters R, Anstey K, Brayne C. A whole-population approach is required for dementia risk reduction. The Lancet Healthy Longevity. 2022;3:e6–e8. [PubMed: 36098322]
• WEF (World Economic Forum). The global risks report 2022. 17th ed. Geneva, Switzerland: World Economic Forum; 2022.
• WHO (World Health Organization). Constitution of the World Health Organization. Geneva, Switzerland: World Health Organization; 1946.
• WHO. For the future: Towards the healthiest and safest region: A vision for the WHO work with member states and partners in the western Pacific. Manila, Philippines: WHO Regional Office for the Western Pacific; 2020.
• WHO. Global report on ageism. Geneva, Switzerland: World Health Organization; 2021a.
• WHO. Ethics and governance of artificial intelligence for health. Geneva, Switzerland: World Health Organization; 2021b.
• WHO. Decade of healthy ageing: Baseline report. Geneva, Switzerland: World Health Organization; 2021c.
• Wolters FJ, Chibnik LB, Waziry R, Anderson R, Berr C, Beiser A, Bis JC, Blacker D, Bos D, Brayne C. Twenty-seven-year time trends in dementia incidence in Europe and the United States: The Alzheimer Cohorts Consortium. Neurology. 2020;95(5):e519–e531. [PMC free article: PMC7455342] [PubMed: 32611641]
• Zelinski EM, Kennison RF. Not your parents' test scores: Cohort reduces psychometric aging effects. Psychology and Aging. 2007;22(3):546. [PMC free article: PMC4169292] [PubMed: 17874953]