Health systems and health in world cities: challenges for the future

Starting in the late twentieth century, and continuing as we move through the 21^st century, human civilization is undergoing fundamental restructuring, driven by two converging trends: rapid urbanization and an unprecedented aging of the global population. By 2050, seven out of ten people will live in cities, and for the first time in history, people age 65 years and over will outnumber children under 5 years. This intersection of mega-trends is transforming cities into critical laboratories for understanding health system performance, urban aging and public health (1).

In this series, we focus on world cities—those with over 10 million inhabitants in high- and upper-middle-income nations, e.g., London, New York, Paris, Tokyo and Shanghai. These cities, among others, have strong global ties to one another and contribute massively to their national economies. They serve as transportation gateways to the rest of the world, bastions of cultural expression and media, and “command centers” for corporate headquarters with their affiliated financial and specialized legal services (2). In many respects, such world cities share more in common with one another than with their respective nation-states. They have been studied along many dimensions; yet there are few studies of world city healthcare systems and the challenges they face (3). The articles in this series all examine urban health inequalities and vulnerabilities through the lens of spatial and demographic analysis in global cities (4-7). Each study investigates how these cities are responding to the needs of their vulnerable populations, including older people, low-income residents, and marginalized ethnic groups.

The city as a unit of analysis: beyond national averages

To deepen our understanding of health system performance, aging and public health, it can be illuminating to look below the level of the nation-state, which is often too large and heterogeneous to offer meaningful insights. Comparing world cities allows us to control for economic variables, while highlighting the effects of local health organizations, because world cities play similar roles in the global economy (8).

The most vital data exist at the “micro-spatial” level—the neighborhood, the census tract, and the street corner. In the modern city, geography often appears to be destiny. A resident’s zip code is often an enormously important factor shaping their health. Studies find that lifecourse residential trajectories predict later-life health, underscoring cumulative place effects (9,10). Need this be the case? While geography seems to dictate destiny, research suggests this is a result of system structure rather than an inherent trait of these neighborhoods. Neighborhood-level differences in health reflect deeply intertwined environmental, socioeconomic, and healthcare-access factors at the local level (11). Public health interventions and urban planning should recognize these vulnerabilities in ways that help cities decouple a resident’s zip code from their health trajectory.

Advantages and penalties

World cities have a dual reality: an urban health advantage of concentrated medical expertise and infrastructure, and an urban health penalty marked by spatial inequality, social isolation, and heightened vulnerability to global change. The coexistence of the urban health advantages and urban health penalties creates a complex city environment for older adults. The advantages are related to the density of high-tier teaching hospitals, specialized care networks and an array of other amenities that contribute to better health. These include accessible and subsidized transportation systems, free museums and concerts, parks, and easily accessible shops and restaurants. Proximity to these resources can lead to better average health outcomes compared to suburban and rural areas.

However, these advantages are frequently neutralized by urban health penalties—poverty, uneven distribution of resources and spatial inequities in access to health services. For example, “healthcare deserts” where medical services are physically present in the city but geographically or economically out of reach for people living in specific neighborhoods. Similarly, there may be “food deserts” where affordable grocery stores do not exist and local residents must purchase food from smaller shops in which the supply of fresh fruits and vegetables is both limited and expensive (12-14).

There is also the problem of social isolation. High-density living does not necessarily lead to social cohesion. Higher urban population density can be associated with more, not less, loneliness and social isolation (15,16). Ironically, high population density, when combined with limited public spaces and high heat, may contribute to social isolation (17,18). Many older residents experience isolation that leads to cognitive decline and poor health (19,20).

Urban systems designed for the young and mobile can become hostile to older people, as well as people living with disabilities. For example, lack of public toilets or safe crossings can effectively “imprison” an older person within their immediate home environment (21). Uneven sidewalks, missing or poor curb ramps, unsafe crossings, traffic, lack of resting places, and limit outdoor activity for people living with mobility limitations (22,23).

The income-health gap in dense environments

While older residents in world cities may appear healthier on average, this “urban advantage” is not shared equally. Even within national systems supported by social safety nets, low-income older adults face significant barriers to specialized care. Access to life-saving procedures remains influenced by income and neighborhood of residence, making “equal treatment for equal need” an elusive goal (6). The built environment, the physical layout of streets and buildings, may contribute to the odds of developing a chronic disease across the life course. Access to “blue and green spaces” (parks and water) acts as a buffer against obesity and diabetes. A systematic review of nineteen studies found that neighborhood green space exposure was associated with lower type-2 diabetes prevalence, lower obesity, and more physical activity (24). Similarly, a 2025 umbrella review found that green space exposure was associated with reduced diabetes and metabolic syndrome, and blue space with lower obesity and better mental health (25).

The landscape of risk: infectious disease and environmental resilience

As critical gateways for health risks from around the world, New York, Paris and London were epicenters for the coronavirus disease 2019 (COVID-19) pandemic and an incubator and transmission belt for many microbial travelers over the 20^th century (26). Their experience in responding to contagious disease has revealed how such wealthy world cities remain vulnerable giants and why public health infrastructure is so important to protect their populations (27).

Likewise, climate change, such as flooding and global warming, introduces new lethal risks to world cities (28). Heat wave events such as the “urban heat island” effect—where concrete and asphalt trap heat—create a deadly environment for those over 75 years (7). This results in predictable, massive surges in hospital workloads for conditions like renal failure and dehydration. Vulnerability in this changing climate can be assessed using the Intergovernmental Panel on Climate Change (IPCC)’s “exposure-sensitivity-adaptive capacity” framework (29). Exposure is the geographic reality of living in hazard zones, e.g., seniors living in flood-prone areas or top-floor walk-up apartments that lack ventilation and become “heat traps” during summer months (30). Sensitivity refers to the physiological and socioeconomic baseline of a population, e.g., older people and the poor are naturally more sensitive to environmental stressors. Advanced age may reduce the body’s ability to regulate temperature, while poverty limits the ability to afford mitigation strategies like air conditioning. Finally, adaptive capacity involves the resources available to survive or evacuate including “hard” resources [income and “soft” resources (social networks)] (31).

Urban design as a public health intervention

The built environment—defined by the physical layout of streets, buildings, and public utilities—is an important determinant of chronic disease. Given the pace of population aging in world cities and the disparities in health system performance among city neighborhoods, urban planning is increasingly recognized as an important component of health policy (32). When a city is designed with the physiological limitations of older people in mind, it acts as a “health multiplier”; when it is not, it becomes a catalyst for decline.

The therapeutic role of blue and green spaces

Access to “blue and green spaces”, such as parks, community gardens, and waterfronts, acts as a vital buffer against prevalent metabolic conditions like obesity and diabetes. Exposure to natural environments has been linked to lower levels of cortisol and improved cognitive function, which may delay the onset of dementia-related symptoms among older residents of cities. These spaces serve as “social infrastructure”, providing a safe, accessible venue for intergenerational interaction, which directly counters the epidemic of social isolation.

Walkability

For an aging population, walkability is more than a convenience; it is often a necessity. A city that lacks basic features like benches, public toilets, and safe, timed crossings effectively “imprisons” its older residents. This physical confinement leads to a predictable cascade of negative outcomes. If older adults perceive streets as unsafe or physically taxing due to a lack of resting points, they are more likely to remain indoors (33). This may lead to muscle atrophy, increased fall risk, and a loss of independence. The inability to navigate the neighborhood independently leads to social withdrawal. In dense world cities, where traditional family structures may be fragmented, the “neighborhood” often provides the only source of daily cognitive stimulation (34,35).

Decoupling geography from destiny

While the current reality suggests that geography is destiny, this need not be a permanent state. The concept of the 15-minute city offers a blueprint for rewriting this narrative (36). By ensuring that essential services—clinics, pharmacies, and fresh food—are within a short, safe walk for all residents, cities can eliminate the “care deserts” thereby alleviating the urban penalty.

Designing a city for the most vulnerable improves the city for everyone. A curb cut designed for a wheelchair also benefits a parent with a stroller; a park designed for a senior’s rest also serves as a cooling center for the entire community. In this way, “age-friendly” design becomes the cornerstone of a resilient, equitable urban future (37).

To operationalize these concepts, urban planning must be integrated with public health. Municipalities should consider “health impact assessments” for new developments to ensure that they contribute to, rather than detract from, the local “urban advantage”. As care moves to tele-health, universal broadband must be treated as a public health necessity. This prevents a new form of “digital geography” from becoming a barrier to care for the urban poor (38).

Conclusion: from economy to sanctuary

The success of our world cities should no longer be measured by the height of their skyscrapers, but by how they care for their most vulnerable citizens. By bridging the fields of health policy and management, aging, urban planning and public health, we can redesign cities that serve not just as engines of economic growth, but as sanctuaries of health and equity for all ages.

Acknowledgments

None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Journal of Hospital Management and Health Policy for the series “Health Systems and Health in World Cities: Challenges for the Future”. The article did not undergo external peer review.

Funding: None.

Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at https://jhmhp.amegroups.com/article/view/10.21037/jhmhp-2026-0030/coif). The series “Health Systems and Health in World Cities: Challenges for the Future” was commissioned by the editorial office without any funding or sponsorship. M.K.G. and V.G.R. served as the unpaid Guest Editors of the series. V.G.R. serves as an unpaid editorial board member of Journal of Hospital Management and Health Policy from September 2024 to December 2026. The authors have no other conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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Michael K. Gusmano

Victor G. Rodwin