Between 1990 C.E. and 2021 C.E., the world added 6.2 years to global life expectancy — one of the most significant gains in recorded public health history. A landmark study published in The Lancet by researchers at the Institute for Health Metrics and Evaluation (IHME) at the University of Washington traced exactly how that happened, disease by disease, region by region. The findings offer a clear-eyed account of what humanity got right, where the COVID-19 pandemic pushed back decades of progress, and what work remains.
At a glance
- Global life expectancy: Rose by 6.2 years between 1990 C.E. and 2021 C.E., driven primarily by sharp declines in deaths from diarrheal diseases, lower respiratory infections, stroke, and ischemic heart disease.
- Regional gains: Eastern sub-Saharan Africa saw the largest regional jump — 10.7 years — largely through control of diarrheal diseases, while Southeast Asia, East Asia, and Oceania led among super-regions with an 8.3-year gain.
- COVID-19 impact: The pandemic caused a 2.2-year global decline in life expectancy in 2021 C.E. and displaced stroke as the second-leading cause of death worldwide for the first time in 30 years.
Three decades of fighting disease
The study draws on the Global Burden of Disease Study 2021, the most comprehensive effort ever made to track health loss across time and place. It involved more than 11,000 collaborators in over 160 countries and produced more than 607 billion estimates covering 371 diseases and injuries.
The headline finding is remarkable: diseases that once killed millions every year have been dramatically reduced. Deaths from enteric diseases — the category that includes diarrhea and typhoid — fell enough to add 1.1 years to global life expectancy on their own. Reductions in lower respiratory infections added another 0.9 years. Progress against stroke, neonatal disorders, ischemic heart disease, and cancer added further gains.
For most of these conditions, the sharpest improvements came in the three decades between 1990 C.E. and 2019 C.E. — before the pandemic arrived.
Where progress was strongest
Some of the most striking gains came from regions that are rarely at the center of global health celebrations.
Eastern sub-Saharan Africa’s 10.7-year gain in life expectancy over the period is extraordinary by any measure. The driving force was the control of diarrheal diseases — an achievement built on expanded access to clean water, oral rehydration therapy, and vaccines. East Asia posted the second-largest gain, with steep reductions in deaths from chronic obstructive pulmonary disease playing a key role.
South Asia added 7.8 years of life expectancy, primarily through cutting deaths from diarrheal diseases. The IHME researchers note that these gains reflect the kind of sustained, targeted public health investment that saves millions of lives without always making headlines.
“On one hand, we see countries’ monumental achievements in preventing deaths from diarrhea and stroke,” said Dr. Liane Ong, co-first author and Lead Research Scientist at IHME. “At the same time, we see how much the COVID-19 pandemic has set us back.”
COVID-19 and the cost of setbacks
The pandemic interrupted three decades of compounding progress. Globally, COVID-19 caused a 2.2-year drop in life expectancy in 2021 C.E. — and it hit some regions far harder than others. Latin America and the Caribbean, along with sub-Saharan Africa, lost the most years of life expectancy due to COVID-19 that year. Meanwhile, the Southeast Asia, East Asia, and Oceania super-region’s early and consistent pandemic management helped it preserve most of its long-term gains.
For the first time in 30 years, the top five global causes of death shifted. COVID-19 moved into the second position globally, displacing stroke. The researchers note this as a warning as much as a data point: the infrastructure that controls infectious disease matters enormously, and uneven pandemic management had measurable, deadly consequences.
The unfinished work
The study also maps where progress has stalled or remains dangerously uneven. Deaths from enteric diseases are now heavily concentrated in sub-Saharan Africa and South Asia. Malaria kills at striking geographic concentration — 90% of deaths in 2021 C.E. occurred in a stretch of land from Western sub-Saharan Africa through Central Africa to Mozambique, a region home to just 12% of the world’s population.
Non-communicable diseases are rising in every country. Diabetes and chronic kidney disease are increasing globally, and the gap between high-income and low-income countries in managing ischemic heart disease, stroke, and cancer remains wide. High-income countries have driven down deaths from many of these conditions through treatments and prevention programs that are simply not yet available everywhere.
“The global community must ensure that the lifesaving tools that have cut deaths from ischemic heart disease, stroke, and other non-communicable diseases in most high-income countries are available to people in all countries, even where resources are limited,” said Eve Wool, senior author and Senior Research Manager at IHME.
Professor Mohsen Naghavi, co-first author and Director of Subnational Burden of Disease Estimation at IHME, pointed to the next frontier in infectious disease prevention: new vaccines against E. coli, norovirus, and Shigella, alongside stronger immunization programs, could eliminate much of the remaining death toll from enteric diseases.
The 6.2-year gain in global life expectancy is not a finish line. It is proof that targeted investment in public health — clean water, vaccines, accessible treatment — produces results at scale. The same logic points clearly toward what needs to happen next. Unresolved inequities in access to medicines and health systems mean that millions of people in low-income countries still face death rates from preventable diseases that wealthy nations reduced decades ago — and closing that gap is now the defining challenge of global health.
Read more
For more on this story, see: Institute for Health Metrics and Evaluation
For more from Good News for Humankind, see:
- U.K. cancer death rates are down to their lowest level on record
- Renewables now make up at least 49% of global power capacity
- The Good News for Humankind archive on global health
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