The Future of Global Health: Forecasting Disease Burden to 2050

Jun, 2024

 

As the world continues to grapple with the lasting impacts of the COVID-19 pandemic, policymakers and public health officials are increasingly focused on understanding what the future may hold for the global disease burden. A comprehensive new analysis published in The Lancet provides critical insights into expected trends in mortality, disability, and life expectancy over the coming decades.

The study, conducted by the Global Burden of Diseases, Injuries, and Risk Factors (GBD) Collaborators, presents detailed forecasts of disease burden for 204 countries and territories from 2022 to 2050. Based on an in-depth analysis of demographic, socioeconomic, and epidemiologic drivers, the researchers model the likely trajectory of 359 different diseases and injuries under a “reference” scenario that assumes a continuation of current trends. They also evaluate the potential impact of eliminating key risk factors through alternative scenarios.

The findings paint a complex and nuanced picture of the global health landscape in the years ahead. While the news is largely positive, with continued improvements in life expectancy and reductions in age-standardized disease burden, the analysis also identifies concerning shifts in the leading causes of disability and mortality that will require concerted policy action.

Importantly, the researchers emphasize that these forecasts are not set in stone. Rather, they represent a starting point for understanding the range of plausible futures – and the critical opportunities that exist to positively shape the health of populations worldwide.

At the highest level, the GBD study’s reference scenario forecasts ongoing gains in global life expectancy, from 73.6 years in 2022 to 78.2 years by 2050. This represents a slowdown compared to the rapid increases seen in the decades preceding the COVID-19 pandemic, but still points to continued progress.

Global and super-regional life expectancy, 1990–2050 for females (A) and males (B)

The improvements are expected to be widespread, with life expectancy rising across all seven GBD super-regions. Notably, the researchers predict the greatest gains will occur in regions that currently have the lowest life expectancies, such as sub-Saharan Africa. This is projected to result in a convergence of life expectancies globally, as the gap narrows between the world’s healthiest and most vulnerable populations.A similar pattern emerges for healthy life expectancy (HALE) – a measure that adjusts life expectancy for time lived with disability. HALE is forecasted to increase from 62.6 years for men and 64.7 years for women in 2022, to 66.0 and 67.5 years respectively by 2050. Again, the most dramatic gains are expected in regions with the lowest starting points.

These findings suggest that, barring major shocks, the world is poised for continued improvements in longevity and general health status over the coming decades. However, the authors note several important caveats.

First, the projected increases, while substantial, are expected to occur at a slower pace than in previous years. This deceleration is attributed to a variety of factors, including the lingering impacts of COVID-19, potential for setbacks in progress against communicable diseases, and the challenges of addressing the growing burden of non-communicable diseases (NCDs).

Second, while life expectancy and HALE are set to rise across the board, significant disparities will remain between locations. Even in 2050, the researchers forecast a nearly 10-year gap in female life expectancy between the high-income super-region (85.3 years) and sub-Saharan Africa (75.5 years). Closing these gaps will require targeted investments and interventions tailored to the unique needs of the world’s most disadvantaged populations.

Beyond the headline trends in longevity, the GBD study’s forecasts reveal a fundamental transformation in the global burden of disease that will have profound implications for health systems and priorities.

Specifically, the analysis projects a continued shift away from communicable, maternal, neonatal, and nutritional (CMNN) diseases toward non-communicable diseases (NCDs). At the global level, the proportion of disability-adjusted life years (DALYs) attributed to NCDs is expected to rise from 64.2% in 2022 to 77.6% by 2050.

Decomposition of change in global and super-regional life expectancy, 2022–50, by Level 2 causes, for reference and combined scenarios

This transition is most dramatic in regions that currently bear the highest CMNN burdens. In sub-Saharan Africa, for instance, CMNN diseases are forecast to account for just 35.8% of DALYs in 2050, down from 60.1% in 2022. A similar shift is predicted for South Asia, where the CMNN share is expected to decline from 31.7% to 15.5% over the same period.Drilling down into the specifics, the researchers identify several key drivers of this epidemiological transformation. At the global level, the top four causes of DALYs in 2050 are projected to be ischemic heart disease, stroke, diabetes, and chronic obstructive pulmonary disease – all non-communicable conditions. This marks a significant change from 2022, when the leading causes were ischemic heart disease, neonatal disorders, stroke, and lower respiratory infections.

The rise of NCDs is not limited to mortality, either. The study also forecasts a growing proportion of the global disease burden to stem from years lived with disability (YLDs) rather than premature mortality. Globally, YLDs are expected to account for 41.1% of total DALYs in 2050, up from 33.8% in 2022.

The shift toward morbidity is most pronounced in sub-Saharan Africa, where YLDs are projected to make up 35.6% of the disease burden by 2050, compared to just 20.1% in 2022. This underscores the growing importance of addressing chronic, disabling conditions in regions that have historically grappled with acute, fatal illnesses.

Implications and Opportunities

The GBD study’s forecasts have far-reaching implications for global health priorities and policies in the decades ahead. While the overall trajectory is one of progress, the analysis also highlights several critical challenges that will require concerted, multi-faceted responses.

First and foremost, the continued rise of NCDs represents a major threat to hard-won gains in life expectancy and healthy life. Ischemic heart disease, stroke, diabetes, chronic respiratory diseases, and other chronic, non-communicable conditions are notoriously difficult to treat, often require lifelong management, and pose substantial economic burdens on health systems.

Addressing this growing NCD epidemic will necessitate a fundamental shift in global health strategies – moving beyond a focus on infectious diseases and maternal/child health, toward a more balanced approach that also tackles the behavioral, metabolic, and environmental drivers of chronic illness. This will entail a range of interventions, from tobacco control and dietary improvements to better management of hypertension, cholesterol, and blood glucose levels.

Importantly, the GBD study’s alternative scenarios demonstrate that significant health gains are possible through concerted efforts to reduce exposure to key risk factors. The researchers estimate that eliminating behavioral and metabolic risks like smoking, unhealthy diet, and high body mass index could reduce the global disease burden by over 15% in 2050, compared to the reference case. Targeting environmental risks, such as unsafe water and air pollution, could yield additional benefits.

Of course, actually achieving these risk factor reductions will be an immense challenge, requiring unprecedented political will, cross-sectoral collaboration, and sustained investments. But the potential payoff, in terms of lives saved and disabilities averted, is substantial.

Beyond the NCD transition, the GBD forecasts also highlight the continued importance of addressing persistent communicable disease challenges, particularly in the world’s most vulnerable regions. While the burden of infectious diseases is expected to decline overall, certain conditions like tuberculosis, malaria, and neglected tropical diseases remain stubbornly high in sub-Saharan Africa and parts of Asia.

Redoubling efforts to combat these longstanding foes will be critical, even as global attention and resources increasingly shift toward NCDs. Failure to maintain focus and funding for communicable disease control could jeopardize hard-won progress and widen existing health inequities between and within countries.

At the same time, the growing prominence of disability as a component of the global disease burden underscores the need for health systems to evolve beyond a narrow focus on mortality reduction. Ensuring access to high-quality rehabilitation services, assistive technologies, and comprehensive care for chronic conditions must become central priorities. This will require innovative financing mechanisms, workforce development, and better integration of disability-focused interventions into universal health coverage schemes.

Lastly, the GBD study’s forecasts underscore the critical importance of continued investment in global health surveillance, research, and data collection. Accurate, timely, and granular information on disease trends, risk factor exposures, and health system performance will be essential for guiding policies, targeting interventions, and tracking progress toward key targets.

Encouragingly, the researchers demonstrate that their modelling framework can produce reasonably accurate short-term forecasts, as evidenced by the skill metrics reported for the 2010-2019 validation period. However, the true test will be the model’s ability to anticipate longer-term shifts in disease patterns and anticipate emerging threats. Ongoing refinement and validation of these forecasting tools should be a priority.

Toward a Healthier Future

The GBD study’s comprehensive disease burden projections offer a sobering, yet ultimately hopeful, vision of global health in the decades ahead. While significant challenges loom, the analysis also points to myriad opportunities to improve lives and enhance human wellbeing on a grand scale.

“The GBD forecasts make clear that the burden of poor health remains disproportionately concentrated in the world’s most disadvantaged populations. Ensuring universal access to essential health services, while also addressing the root causes of health disparities, will be essential for achieving a truly equitable future”.

Fundamentally, the forecasts underscore that progress is possible – but it will require a concerted, multi-pronged effort that goes well beyond the traditional domain of the health sector. Effectively navigating the epidemiologic transition, from communicable to non-communicable diseases, will demand unprecedented levels of political commitment, cross-sectoral collaboration, and long-term investment.

Policymakers, public health leaders, and global development partners must be prepared to adapt their strategies, priorities, and resource allocation models to match the evolving landscape. This will entail strengthening health systems’ capacity to address chronic diseases, while also maintaining vigilance and focus on unfinished communicable disease agendas. Critically, it will also necessitate bold action to tackle the social, economic, and environmental determinants that drive both communicable and non-communicable illness.

Underlying all of this must be a renewed emphasis on equity – both within countries and globally. The GBD forecasts make clear that the burden of poor health remains disproportionately concentrated in the world’s most disadvantaged populations. Ensuring universal access to essential health services, while also addressing the root causes of health disparities, will be essential for achieving a truly equitable future.

Ultimately, the path forward will not be easy. But the GBD study’s projections offer a clear roadmap – and a powerful call to action. By heeding the lessons of this analysis and marshaling the political will and resources required, global health leaders have an unprecedented opportunity to extend the arc of progress, secure lasting improvements in human wellbeing, and deliver on the promise of health for all.

Reference(s)

  1. Wang, W., Volkow, N.D., Berger, N.A. et al. Associations of semaglutide with incidence and recurrence of alcohol use disorder in real-world population. Nat Commun 15, 4548 (2024). https://doi.org/10.1038/s41467-024-48780-6

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FORECASTING | GLOBAL HEALTH | MEDICINE | PHARMACEUTICAL MEDICINE | SOCIETY

About the Author

  • Dilruwan Herath

    Dilruwan Herath is a British infectious disease physician and pharmaceutical medical executive with over 25 years of experience. As a doctor, he specialized in infectious diseases and immunology, developing a resolute focus on public health impact. Throughout his career, Dr. Herath has held several senior medical leadership roles in large global pharmaceutical companies, leading transformative clinical changes and ensuring access to innovative medicines. Currently, he serves as an expert member for the Faculty of Pharmaceutical Medicine on it Infectious Disease Commitee and continues advising life sciences companies. When not practicing medicine, Dr. Herath enjoys painting landscapes, motorsports, computer programming, and spending time with his young family. He maintains an avid interest in science and technology. He is a founder of DarkDrug

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