Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950-2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021.
Level 3 - non-randomized controlled study
Level 3 by design analogy: comprehensive population-level demographic modeling and longitudinal synthesis across global data systems.
PubMed 38484753 · doi:10.1016/S0140-6736(24)00476-8
What was done
The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 estimated age-sex-specific mortality, life expectancy, and population trends across 204 countries and territories and 811 subnational locations from 1950 to 2021. The authors synthesized 22,223 mortality data sources (vital and sample registration, surveys, censuses) and 2,026 population sources. Under-5 and adult (ages 15–59) mortality rates were generated using spatiotemporal Gaussian process regression (ST-GPR) and used to build model life tables (with adjustments for HIV). Excess mortality for 2020–2021 was calculated by subtracting ensemble-modeled expected mortality from observed all-cause mortality, using covariate regression where data were missing. Population size was estimated using a Bayesian hierarchical cohort component model.
What was found
Global age-standardized mortality decreased by 62.8% (95% UI 60.5–65.1) between 1950 and 2019, then rose by 5.1% (0.9–9.6) during 2020–2021. Global life expectancy at birth increased by 22.7 years (20.8–24.8) between 1950 and 2021 (49.0 to 71.7 years), but declined by 1.6 years (1.0–2.2) between 2019 and 2021, increasing in only 32 of 204 countries. Of 131 million (126–137) global deaths in 2020–2021 combined, 15.9 million (14.7–17.2) were excess deaths due to the COVID-19 pandemic. Under-5 deaths continued to decrease from 5.21 million (4.50–6.01) in 2019 to 4.66 million (3.98–5.50) in 2021. Global population reached 7.89 billion (7.67–8.13) in 2021, by which point 56 countries had peaked and begun declining.
Why it matters
This study provides a definitive macro-demographic benchmark of global mortality, showing that COVID-19 produced the first widespread reversal in global life expectancy in over 70 years while accelerating population aging.
Limits
In location-years lacking reliable vital registration or all-cause mortality data, excess mortality and baseline trends relied on statistical imputation and covariate regression models. Excess mortality captures both direct SARS-CoV-2 infection deaths and indirect social or healthcare disruptions without distinguishing between them in the abstract.
Cited by
- context The underlying universal biological process of aging causes approximately 150,000 to 200,000 human deaths each day globally.