The intellectual foundation of the new framework traces back more than half a century. In 1971, Abdel Omran published his landmark formulation of the epidemiological transition in the Milbank Memorial Fund Quarterly, describing how societies move through stages in which pestilence and famine give way to receding pandemics, and eventually to degenerative and man-made diseases as the leading causes of death. Omran’s model became one of the most cited organizing ideas in global health, shaping decades of assumptions about how mortality patterns evolve as nations develop. For generations of researchers and planners, the transition implied a kind of linear progression: as incomes rose and sanitation improved, infectious disease would recede and chronic, non-communicable conditions would take their place. The new work by Ashwin, Bloom, Lee, Piot and Scott builds directly on that lineage but departs from it in a crucial way, replacing the narrative of sequential stages with a statistical categorization that reflects the messy, overlapping reality of disease in the twenty-first century.

At the heart of the proposal is a data-driven taxonomy that assigns diseases to four categories defined by the life stages in which they exert their greatest toll. One category captures the classic afflictions of early life, including the infectious diseases, nutritional deficiencies and neonatal conditions that historically dominated mortality in low-income settings. A second encompasses injuries and other conditions that strike across the working years. A third covers diseases concentrated in later life, and the fourth, the category the authors identify as dominant, consists of aging-related diseases, conditions whose incidence rises steeply as biological aging advances. Rather than treating these categories as successive phases through which a country passes, the framework treats them as concurrent burdens whose relative weights shift with demography, development and policy. The statistical approach allows researchers to quantify how much of a nation’s disease burden falls into each category and to track how those proportions change over time, offering a more granular and actionable picture than the traditional stage-based narrative.

What the analysis reveals is striking. Aging-related diseases, a grouping that includes many of the cardiovascular conditions, cancers, neurodegenerative disorders and other chronic illnesses whose risk escalates with age, now represent the dominant category of disease burden globally. This is not simply because people are living longer, although they are; it reflects the compounding effect of demographic change on disease statistics. As the share of older adults in a population grows, conditions that cluster in later life inevitably account for a larger fraction of total illness and death. But the framework also makes clear that the other three categories have not disappeared. In much of sub-Saharan Africa and parts of South Asia, childhood infections, maternal complications and neonatal disorders remain leading causes of lost healthy years, even as non-communicable diseases surge in the same populations. The figure accompanying Dieleman’s commentary captures this tension in a single image: the world is aging, but most countries still carry all four disease burdens at once.

The persistence of the double burden is the analytical pivot of the commentary. The double burden of disease, a term long used in nutrition and global health circles to describe the coexistence of undernutrition and obesity, or of infectious and chronic disease, is here extended to the full spectrum of illness. Countries that once might have been classified as being in an early stage of the epidemiological transition are simultaneously confronting the diseases of aging, often with health systems built for neither. Dieleman points to evidence from the Global Burden of Disease enterprise, including the GBD 2023 Diseases and Injuries Collaborators’ comprehensive assessment published in The Lancet, which documents how the composition of disease burden has shifted unevenly across regions. High-income countries have largely completed the shift toward chronic disease but now face the escalating costs of multimorbidity, in which patients accumulate multiple aging-related conditions that interact and complicate treatment. Low- and middle-income countries face the harder problem of managing both ends of the spectrum with constrained budgets and thin clinical workforces.

The clustering of aging-related diseases is a central technical concern of the new framing. Unlike many infectious diseases, which follow acute episodes and either resolve or kill within weeks, aging-related conditions tend to be chronic, progressive and mutually reinforcing. Diabetes accelerates cardiovascular disease; cardiovascular disease raises the risk of dementia; sarcopenia and frailty compound the disability caused by arthritis and osteoporosis. Because these conditions cluster within individuals and accumulate over decades, their combined burden spans many years of life, generating sustained demand for continuous care rather than episodic intervention. This temporal profile has profound implications for health economics. A health system oriented toward acute treatment, with hospitals, specialists and pharmaceutical interventions organized around discrete episodes of illness, is poorly matched to a disease landscape in which the dominant conditions require decades of management, coordination across specialties and support for daily functioning outside clinical settings.

It is from this mismatch that Dieleman draws the commentary’s central policy argument: health systems must pivot from treating disease to preserving health. The phrase signals a shift in orientation from downstream intervention to upstream investment, and the authors of the underlying study, along with Dieleman, argue that such investment must begin in all life stages, not merely in old age. The rationale is grounded in the biology of aging itself. Research highlighted in the field, including the influential 2014 position statement by Kennedy and colleagues in Cell, has established that aging is a modifiable risk factor shared by many chronic diseases, and that interventions which slow biological aging processes can delay or reduce the onset of multiple conditions simultaneously. In practical terms, investments in early-life nutrition, childhood immunization, adolescent health, adult prevention of hypertension and diabetes, and the social determinants of health across the entire life course all feed into the trajectory of aging-related disease decades later. A health system that waits until patients are elderly to address these conditions has already lost much of its leverage.

This life-course perspective aligns with a growing body of policy scholarship. Work by Kuruvilla and colleagues published in the Bulletin of the World Health Organization has articulated the case for life-course approaches to health, and analyses by Jamison and colleagues in The Lancet have mapped the essential investments that countries can make at each stage of development to improve health outcomes efficiently. Studies by Bollyky and colleagues in Health Affairs have further documented how the burden of chronic disease in developing countries is intertwined with economic growth and demographic change, complicating the old assumption that prosperity automatically solves chronic disease. The new statistical framing by Ashwin and colleagues gives these arguments a sharper analytical edge by providing a common metric, the four-category disease taxonomy, against which countries can measure their current burdens, project future trajectories and prioritize investments. It also offers a way to compare nations that are at very different points in their demographic transitions without forcing them into a single linear model that may describe none of them accurately.

The implications for global health financing are considerable. Donor institutions and national governments have long organized funding streams around disease categories and life stages in silos: one budget line for child survival, another for HIV and tuberculosis, another for non-communicable diseases, another for aging and long-term care. The four-category framework suggests that these silos are not merely administratively convenient but analytically misleading, because the burdens interact and the most efficient interventions often cut across them. Dieleman’s commentary, published as a News and Views perspective in Nature Aging on 7 September 2026, does not prescribe a specific financing formula, but its message is unambiguous. As aging-related diseases become the dominant category of global illness, and as most countries continue to shoulder the infectious, maternal and childhood burdens of earlier transitions, the health systems that succeed will be those that stop treating aging populations as an afterthought and start investing in health preservation from the first years of life onward. The double burden is not a transitional inconvenience to be waited out; it is the permanent operating condition of modern global health, and policy must be built to match it.

Subject of Research: A statistical reframing of the epidemiological transition that categorizes global diseases into four life-stage groups and highlights aging-related diseases as the dominant burden

Article Title: Aging rises, yet the double burden of illness remains

Article References: Dieleman, J. L. (2026). Aging rises, yet the double burden of illness remains. Nature Aging. https://doi.org/10.1038/s43587-026-01218-8

Image Credits: AI Generated

DOI: 10.1038/s43587-026-01218-8

Keywords: epidemiological transition, aging-related diseases, global disease burden, double burden of disease, health systems, life-course health, non-communicable diseases, demographic change, global health financing, multimorbidity, disease taxonomy, health policy

The review, led by Julia Feriato Corvetto and Robin Simion of the Heidelberg Institute of Global Health at Heidelberg University, together with Perla Boutros, Nour Kassem, Kristine Belesova, Till Bärnighausen, Rainer Sauerborn and senior author Sandra Barteit, was conducted according to the PRISMA-ScR reporting guidelines and pre-registered with the international PROSPERO registry. The team searched four major databases—PubMed, Embase, Web of Science and Scopus—for peer-reviewed studies published up to November 26, 2024. From 15,538 records initially identified, 12,291 were screened by title and abstract, 545 underwent full-text review, and after rigorous eligibility checks, 199 studies remained. Each was charted by exposure type, health outcome, study design and geographic region, with the attributable fraction serving as the standardized metric that allowed otherwise heterogeneous research to be compared on common ground.

The attributable fraction, or AF, expresses the proportion of health outcomes—deaths, hospital admissions, emergency department visits—that can be linked to a specific exposure. Unlike composite metrics such as disability-adjusted life years, which demand granular data on disease severity and duration, the AF requires fewer inputs and can be calculated from established exposure–response relationships, making it particularly valuable in data-constrained settings. The Heidelberg team used it deliberately as a common currency. Where the evidence base allowed, they went further, performing selective random-effects meta-analyses using DerSimonian-Laird models with logit-transformed estimates and inverse-variance weighting, pooling results only for heat-related mortality outcomes that were methodologically comparable.

The pooled figures are sobering. Across 16 eligible studies, heat exposure accounted for 1.18 percent of all-cause mortality, with a 95 percent confidence interval of 1.01 to 1.37 percent. For cardiovascular mortality, ten studies yielded a pooled attributable fraction of 2.15 percent; for respiratory mortality, five studies produced 3.08 percent; and for stroke mortality, five studies gave 2.71 percent. In practical terms, this means that more than one in every fifty cardiovascular deaths in the studied populations was linked to heat. The researchers caution, however, that heterogeneity across studies was extreme—I² statistics reached 100 percent in every pooled analysis—reflecting differences in exposure thresholds, temperature metrics, population vulnerability and statistical modeling. The pooled values, they stress, should be read as indicative central tendencies rather than precise, universally applicable effect sizes.

Beyond the meta-analysis, the descriptive synthesis revealed a startling breadth of climate-sensitive health impacts. Fifteen distinct disease categories emerged from the International Classification of Diseases framework, including respiratory conditions, cardiovascular disease, infectious diseases, neoplasms, endocrine and metabolic disorders, mental and behavioral disorders, neurological conditions, digestive diseases, kidney and genitourinary conditions, and pregnancy-related outcomes. Heat was associated with an attributable fraction of 3.17 percent for all-cause mortality in the broader synthesis and, strikingly, with nearly 10 percent of suicide mortality in single-country evidence. Temperature variability—the fluctuation of temperatures between and within days—was linked to 5.57 percent of cardiovascular mortality and 3.28 percent of all-cause deaths. Ambient air pollution showed associations with 5.57 percent of all-cause mortality and more than 9 percent of deaths from mental disorders including dementia, though with wide uncertainty intervals that reflect the challenge of separating climatic from industrial pollution sources.

Perhaps the most striking single estimate concerned extreme weather events and mental health: floods, storms and droughts were associated with an attributable fraction exceeding 20 percent for mortality from mental disorders. Drowning showed a similarly strong signal, with 11.40 percent of drowning deaths tied to extreme events. On the morbidity side, heat exposure accounted for 6.41 percent of genitourinary disease admissions, including acute kidney injury, and 9.65 percent of infectious disease morbidity, while temperature variability was linked to 8.59 percent of cardiovascular hospitalizations. Combined exposures—temperature and air pollution acting together—pushed attributable fractions as high as 16.65 percent in individual studies, underscoring the growing recognition that compound hazards may pose risks greater than the sum of their parts.

Yet the review’s most consequential finding may be what it reveals about the geography of knowledge itself. Of the 199 included studies, 116 were conducted in China alone, followed by Brazil with 24 and Spain with 20. The overwhelming majority came from high- and upper-middle-income countries, and the evidence base leaned heavily on administrative healthcare data—hospital and emergency department records—rather than population-based surveys. Only three studies relied on nationally representative survey data. This means the evidence skews toward populations with reliable access to health systems, leaving the burden among marginalized communities, informal settlements and remote rural populations largely invisible. The authors identified acute evidence gaps for undernutrition, injuries, disabilities and non-fatal outcomes, particularly across sub-Saharan Africa, South and Southeast Asia, and Latin America.

The team was careful to distinguish between evidence density and true burden. The dominance of heat-related cardiovascular and respiratory outcomes in the literature, they note, reflects where researchers have concentrated their effort—not necessarily where the greatest health toll lies. Studies of extreme weather events remain relatively rare, and methodological inconsistency compounds the problem: the review catalogued twelve distinct definitions of heat exposure in use across the field, from mean temperature above the minimum mortality temperature to percentile-based thresholds, heatwave duration criteria, wet-bulb globe temperature and the excess heat factor. Counterfactual definitions—what counts as the “baseline” against which excess deaths are measured—vary just as widely, making direct comparison across studies treacherous.

The review builds on and extends earlier syntheses. Cheng and colleagues’ 2019 global review had estimated that more than 2.5 percent of deaths in high-income countries and over 3 percent in middle-income countries were attributable to non-optimal temperatures, but it excluded air pollution and extreme weather events and aggregated findings by country income level. The Wellcome Trust’s 2024 assessment of formal attribution science screened nearly 4,000 studies and found only 13 rigorous enough to attribute health outcomes specifically to anthropogenic climate change, most focused narrowly on heat mortality. The new review captures the post-2018 surge in the literature—197 of its 199 studies were published since that year—and covers 15 disease subgroups across exposures far beyond temperature alone. Notably, the years 2023 and 2024 show marked acceleration, with emerging representation from climate-vulnerable regions, largely driven by multi-country study designs.

The findings carry direct implications for international climate policy. Burden estimates of this kind are increasingly relevant to the “loss and damage” fund formalized at COP28, which aims to compensate vulnerable countries for climate impacts, and to the economic accounting frameworks that trace back to the Stern Review’s conclusion that health damages constitute a significant share of climate change costs. The authors argue that attributable-fraction-based indicators should be integrated into National Adaptation Plans, heat–health action plans and public health preparedness strategies, and they call on the World Health Organization and multilateral agencies to develop harmonized exposure definitions and reporting conventions aligned with the Global Burden of Disease framework and IPCC assessment processes.

On the research side, the review advocates sustained investment in longitudinal, population-based surveillance platforms, including Health and Demographic Surveillance Systems and emerging climate-health infrastructures such as the Climate Change and Health Evaluation and Response System, particularly in low- and middle-income countries. Expanding data sources beyond hospital records, the authors argue, is essential to capture non-fatal outcomes and marginalized populations that administrative datasets systematically miss. They also propose a three-axis research prioritization framework spanning geographic vulnerability, exposure complexity and underrepresented outcome domains—mental health, renal disease, infectious disease and occupational outcomes chief among them.

The authors acknowledge limitations: the very high heterogeneity that constrains generalization, the reliance on healthcare utilization data that likely underestimates burden in low-access settings, the exclusion of cold-related attributable fractions on the grounds that cold extremes are declining under warming trends, and the inherent difficulty of isolating the anthropogenic climate signal from natural variability in the observed exposure–response relationships. Ambient air pollution’s dual nature—partially climate-sensitive through meteorology but largely driven by industrial and transport sources—was handled with explicit caution.

Even with these caveats, the review delivers an empirical foundation that attribution science has lacked. It demonstrates that climate-sensitive exposures are not a distant or hypothetical threat but a quantifiable, present-day driver of death and disease across cardiovascular, respiratory, renal, infectious and mental health domains. As heatwaves intensify, floods lengthen and temperature swings widen, the population-level burden will grow even if individual risks remain constant—unless, as the authors insist, surveillance systems, methodological standards and adaptation financing catch up with the scale of the hazard. Quantifying the damage, they argue, is the first step toward making the world’s response to climate change’s health toll both evidence-based and equitable.

Using data from the Global Burden of Disease 2021, researchers applied advanced statistical techniques, including Joinpoint regression and random forest modeling, to dissect the intricate relationships between PAH incidence and the prevalence of various hemolytic disorders. The findings were striking: while PAH age-standardized incidence rates (ASIR) modestly increased worldwide from 0.50 to 0.52 per 100,000 people between 1990 and 2021, the strongest predictor of this rise was not socio-demographic factors but hemolysis-associated conditions.

Specifically, variants of glucose-6-phosphate dehydrogenase (G6PD) deficiency, a common genetic trait affecting red blood cell stability, emerged as the top contributor to PAH incidence. Other hemoglobinopathies and hemolytic anemias of uncertain origin also displayed robust positive correlations with PAH rates. Intriguingly, vitamin A deficiency—known to impact red blood cell health—was another critical and previously underappreciated driver identified in this model, surpassing the influence of the socio-demographic index and sex differences.

The employment of random forest regression explained an impressive 73% of the variance in PAH incidence globally, underscoring the potency of hemolytic disorder prevalence as a predictive factor. Temporal trends further reinforced these conclusions, revealing parallel increases in hemolytic disorder prevalence and PAH incidence, with a high correlation coefficient of 0.76.

In addition to genetic and nutritional contributors, the study’s exploratory investigations hinted that environmental exposures to natural products could be an underrecognized influence on the hemolytic burden, potentially exacerbating PAH risks in exposed populations. This novel insight opens new avenues for research into environmental triggers of hemolysis-mediated cardiovascular pathology.

Looking ahead, sophisticated Bayesian age-period-cohort models project a continued rise in both PAH burden and hemolytic disease prevalence through 2050. These projections predict that PAH incidence will climb to 0.57 per 100,000 people, while hemolytic disorder prevalence is expected to escalate from approximately 27,760 to over 31,800 cases per 100,000 globally. Such trends highlight the urgent need for public health strategies that prioritize the identification, prevention, and management of hemolysis-associated conditions.

This landmark study fundamentally reorients the understanding of PAH epidemiology by establishing hemolytic disorders—not just traditional socio-demographic factors—as key and modifiable drivers of disease burden. It advocates for a paradigm shift in global health policy to incorporate hemolytic disorder screening and treatment into pulmonary hypertension prevention programs, potentially mitigating a significant and growing cause of cardiovascular morbidity worldwide.

Published in the peer-reviewed journal Future Integrative Medicine, these findings promise to catalyze further translational and clinical research, illuminating the path toward innovative therapies personalized to hemolytic disease profiles. As the global healthcare community grapples with the rising tide of PAH, this work underscores the critical intersection of genetics, nutrition, environmental factors, and cardiovascular health.

Subject of Research: Hemolysis-associated disorders and their contribution to pulmonary arterial hypertension incidence
Article Title: Hemolysis-associated Disorder and Natural Product Exposures: Underrecognized Drivers of an Escalating Global Pulmonary Arterial Hypertension Burden—An Ecological Study of 204 Countries and Territories
News Publication Date: June 18, 2026
Web References: http://dx.doi.org/10.14218/FIM.2026.00004
Keywords: Pulmonary arterial hypertension, hemolysis, G6PD deficiency, hemoglobinopathies, vitamin A deficiency, global health, epidemiology