Abstract
IMPORTANCE: Persistent disparities in mortality across countries suggest uneven improvements in living standards and access to life-extending health technologies, as well as context-specific obstacles. Studies have analyzed cross-country inequality in mortality but have not widely contextualized those disparities in terms of developmental progress relative to a frontier representing a level of mortality achievable with broad access to the best health-enhancing technology and living standards available. OBJECTIVE: To examine probability of premature death (PPD)-defined as probability of dying before 70 years of age-across countries and regions, benchmarking progress as years behind the lowest country-level PPD (the frontier). DESIGN AND SETTING: This cross-sectional study used aggregate-level data from the 2024 United Nations World Population Prospects and Human Mortality Database to calculate PPD across 7 global regions and the 30 most populous countries. Data were analyzed from May to September 2025. MAIN OUTCOME AND MEASURES: The primary outcomes were PPD and the number of years behind the lowest country-level PPD. RESULTS: The frontier PPD fell from 57% to 12% from 1900 to 2019. Sub-Saharan Africa's PPD in 2019 was 52%, corresponding to the 1916 frontier PPD. However, sub-Saharan Africa had converged toward the frontier by over 40 years since 2000, when it had a 65% PPD. China has been converging toward the frontier since 1970, having been 93 years behind the frontier PPD in 1970 (with a 60% PPD) and 35 years behind in 2019 (21% PPD). The US has diverged away from the frontier, having been 29 years behind in 1970 (38% PPD) and 38 years in 2019 (22% PPD). Of the regions included, the North Atlantic (Western Europe and Canada) was the closest to the frontier, being 13 years behind in 2019 (15% PPD). The US, Central and Eastern Europe, and sub-Saharan Africa were the furthest above the 2019 PPD Preston curve (ie, they had a greater PPD than predicted by their per capita gross domestic product). CONCLUSIONS AND RELEVANCE: In this cross-sectional study, disparities in PPD were likely to reflect major inequality in access to health-enhancing technologies and living standards, as well as context-specific obstacles. Technological and medical advancements leading to universal health benefits need to be rapidly and fairly disseminated.