Decomposition of cross-country socioeconomic inequality in mortality by 288 causes of death and 84 risk factors from 1990 to 2021.

Global cross-country socioeconomic inequalities in all-cause age-standardized mortality (SIAM) have persisted over decades, but major contributing causes and risk factors remain unclear. Here, we quantified contributions of 288 causes and 84 risk factors to SIAM using the Global Burden of Disease Study 2021 (GBD 2021). From 1990 to 2021, communicable, maternal, neonatal, and nutritional diseases' contribution fell from 81.2% to 56.6%, while non-communicable diseases' contribution from 13.2% to 27.8%. The top five causes of death contributing to SIAM in 2021 were COVID-19 (17.9%), stroke (9.4%), tuberculosis (7.3%), lower respiratory infections (7.0%), and diarrheal diseases (5.5%). The top five risk factors contributing to SIAM in 2021 were household air pollution from solid fuels (17.2%), high systolic blood pressure (9.9%), unsafe sex (4.6%), high fasting plasma glucose (4.4%), and unsafe water sources (4.2%). Overall, this study provides policymakers with data to promote global health equity by targeting key causes and risk factors contributing to cross-country mortality inequality.