Neonatal Disorders Across the Development Gradient: Inequality Divergence and Future Trajectories

Purpose: To characterise the global burden of neonatal disorders across the socio-demographic development gradient, with emphasis on temporal trends, absolute and relative inequality, attributable risks, and future trajectories. Methods: Using Global Burden of Disease 2021 data, we analysed age-standardised incidence, prevalence, mortality, and disability-adjusted life-year (DALY) rates across 204 countries and territories from 1990 to 2021. Temporal trends were quantified using estimated annual percentage change. Development-related inequality was assessed using the slope index of inequality and concentration index. Attributable burden was evaluated for low birth weight, short gestation, ambient particulate matter pollution, and household air pollution from solid fuels. UN IGME neonatal mortality estimates were used for external validation. Trends to 2050 were projected using ARIMA, ETS, and ARIMAX-SDI models. Results: In 2021, neonatal disorders remained disproportionately concentrated in low-SDI settings, particularly sub-Saharan Africa and South Asia. Mortality and DALY rates declined substantially from 1990 to 2021, whereas incidence and prevalence showed less favourable trends. Absolute inequality narrowed, but relative inequality widened, indicating that progress was not distributed proportionately across the development gradient. Preterm birth was the leading burden component, while low birth weight and short gestation were the dominant attributable risks. Projections suggested continued declines in mortality and DALY rates but increasing prevalence through 2050. Conclusion: Neonatal disorders remain a development-sensitive global health burden. Strategies should extend beyond mortality reduction to include prevention of prematurity and low birth weight, mitigation of context-specific environmental risks, and long-term care for morbidity among survivors.