A Cross-National Analysis of Lifespan Inequality, 1950-2015: Examining the Distribution of Mortality Within Countries

Cross-national health research devotes considerable attention to lifespan and survival rate disparities that are found between countries. However, the distribution of mortality across the world is shaped mostly by what happens within countries. We address this striking gap in the literature by modeling length-of-life inequality for individual nation-states. We use life tables from the United Nation's (2015) World Population Prospects to estimate inequality levels for 200 countries across 13 waves between 1950 and 2015. We find that lifespan inequality is steadily declining across the world, but that each country's level of inequality, and the rate at which it declines, vary considerably. Our models account for more than 90% of the longitudinal and cross-sectional variation in country-level lifespan inequality during the 1990-2015 period. Maternal mortality is the strongest predictor in our model, while disease prevalence, access to safe water, and health interventions figure prominently, as well. Gross domestic product per capita shows the expected curvilinear association with lifespan inequality, while primary education (both overall enrollment and gender equity in enrollment), external debt, and migration also play critical roles in shaping health outcomes. By contrast, the distribution of political and economic resources (i.e., democracy and income inequality) is less important.