What the World Can Teach the United States about Aging

Populations around the world are aging, and fast. Here in the United States, not only is the population getting older, but it’s doing so in the shadow of a long-standing health disadvantage relative to high-income peer nations. For example, the US experiences lower life expectancy and greater preventable mortality than nations like Australia, Canada, France, Germany, the Netherlands, New Zealand, Sweden, Switzerland, and the United Kingdom.¹ As population health researchers studying health and aging around the world, we see firsthand how global data are indispensable if we are to devise solutions that address the health disadvantage facing our rapidly aging American population.

A 2024 report by The Commonwealth Fund¹ used the adage “mirror, mirror” to illustrate the importance of global data to show what the US health care system does well and where it lags. Though the US performs well on health care processes and guideline compliance, it trails peer nations on every other health system indicator. The US statistics are sobering, with lower life expectancy, more chronic disease and obesity, and excessive high-risk behaviors.² Yet, the US remains without universal health coverage, continues to outspend other nations on health care, and faces massive differences in health outcomes between haves and have-nots.³

In a similar vein, this kind of mirror is valuable for illuminating how social, public health, and economic policies could be tweaked to promote healthier and more economically secure aging in the US. To this end, the National Institute on Aging (NIA) at the US National Institutes of Health has been a driving force in developing global aging research networks – networks that now represent more than 70% of the world’s population over age 60. Together, the Health and Retirement Study Around the World (HRS-ATW) and Harmonized Cognitive Assessment Protocol (HCAP) Networks are shaping actionable insights to make late-life healthier and wealthier.

These networks and their studies are the result of strategic investments by NIA. They cultivate principles like data harmonization and data sharing that make data more valuable – optimizing access, usability, and comparability. Owing to NIA’s leadership, foreign governments and private funders alike have been brought to the table to co-fund key studies. The resulting global networks are now transforming our understanding of aging around the world, while also providing an invaluable “global mirror” for the US.

Income Inequalities in Later-Life Health and Mortality

High-income nations in Europe are valuable comparators for understanding health in the United States. The prevalence of functional disability, cancer, diabetes, and high blood pressure is higher in US middle-aged and older adults than among peers in England – especially among those with the fewest resources.⁴ In fact, a recent study in the New England Journal of Medicine showed that the richest 25% of middle-aged and older Americans have similar mortality rates to the poorest 25% of Northern and Western Europeans.⁵

Without comparable global data from the HRS-ATW Network, this alarming US health disadvantage would be indiscernible. Indeed, the demographic aging of the US population lags about 10 to 15 years behind Europe. Looking to Europe as a sentinel “living laboratory” can aid the United States as it faces challenges addressing issues like long-term care that are directly linked to population aging.

Retirement and Cognitive Decline

As retirement ages shift, older adults are reentering and remaining longer in the workforce. Might these extra working years protect against cognitive decline? Differences in retirement and pension policies across countries can help to shed light on the answers to this question in ways that US data cannot do alone. Ample research has shown that remaining engaged in paid work protects against cognitive decline across societies. The direct intellectual stimulation, social engagement, sense of purpose, and income benefits may have positive effects on brain health.

Recently, researchers asked whether there was a cognitive benefit to reentering the labor market after initial retirement.⁶ Looking at the US and South Korea, they used harmonized data from the HRS-ATW. Here, South Korea was a valuable comparator to the United States as a high-income nation with very high formal labor participation in later-life.

It turns out that reentering the labor market in South Korea was cognitively protective, yet it had no impact in the United States.⁶ This comparison suggests what could be possible in the United States. The American workplace, if reengineered to provide age-friendly work environments that are supportive and cognitively stimulating, might provide a path to cognitive resilience. Given the high cost of dementia in the United States – estimated at $781 billion in 2025⁷ – this type of policy intervention could have a sizable impact.

Looking into the Mirror

The US health disadvantage cannot be understood in a domestic vacuum. The reality that other societies have engineered later-life resilience into social, economic, and public health systems shows that it can be done. As the US population continues to age, there is an increasing urgency to look into the global mirror and to do better for our aging population.

In fact, the size and quality of this mirror is growing. Newer studies like the Longitudinal Study of Health and Ageing in Kenya (LOSHAK), the Longitudinal Study of Aging in Guatemala (AGUA), and the Zambian Cohort for Healthy Aging and Dementia (Z-CHAD) are joining studies from more than 40 other countries in the HRS-ATW and HCAP Networks.

Studies like LOSHAK, AGUA, and Z-CHAD are transforming our understanding of how culture, economics, and social structures shape later-life in those settings. Low- or middle-income countries like Kenya, Guatemala, and Zambia may appear, at first glance, to offer fewer lessons about healthy aging in the United States. The reality is that some highly impactful issues – food and water insecurity, high levels of air pollution, and so on – are tougher to study in high-income settings where they’re much less common, but no less impactful. The wide breadth of harmonized aging studies across the world is helping to clarify the role of highly varied exposures, regulatory frameworks, and resilience factors that are important for older adults in the United States and beyond.

Substantial resources are required to sustain and expand the collection of comparable data across the globe, to conduct cross-national data analyses, and to translate evidence into practice. Given rapid population aging and the marked US health disadvantage, sustaining and expanding global aging research using carefully harmonized approaches is a shrewd move. No doubt, these data are important resources throughout the world. Equally clear, however, is that a US investment in global aging research is not charity – it’s also a smart long-term investment in healthy longevity for Americans.

Acknowledgements

JRE and LK jointly conceptualized and wrote this manuscript. JRE and LK both receive funding for their research from the National Institute on Aging and LK is a multiple principal investigator of the Harmonized Cognitive Assessment Protocol Network. This work did not receive any grant funding and the views presented do not represent the views of any funding agency.

About the Authors