Trends in health inequalities across the world's population: an analysis of mortality inequalities by country gross domestic product (GDP) between 1990 and 2022.

BACKGROUND: Life expectancy has increased worldwide, in part due to reduced infant mortality. However, inequalities between countries persist. Gross domestic product (GDP) is a widely used means of assessing a country's economic performance. We assessed global trends in inequalities in life expectancy and infant mortality comparing countries ranked by GDP per capita from 1990 to 2022. METHODS: Data on life expectancy, infant mortality rate, GDP per capita (nominal US$) and population size worldwide for 1990 to 2022 were retrieved from the World Bank. Slope and Relative Indices of Inequality were calculated using regression models to estimate global health inequalities across GDP-ranked countries with weights for population size to represent the global population. RESULTS: The global gap in life expectancy at birth reduced from 28.80 to 19.88 years between 1990 and 2022, while relative inequalities fell from 1.61 to 1.32. The absolute gap in infant mortality fell from 116.97 deaths per 1000 live births to 48.31 but relative inequalities increased (6.76 to 11.38). Progress in levels of global inequality stalled after 2010, with increasing inequalities after 2019. For life expectancy at age 60, both absolute and relative inequalities increased over time from 5.67 to 7.77 years and 1.41 to 1.50, respectively. CONCLUSION: Progress has been made in reducing health inequalities across the global population since 1990, but this has slowed for over a decade, and inequalities in life expectancy at age 60 have increased. Global policy initiatives to address global health inequalities and particularly older age adult mortality are needed.