Epidemiological Trends of Air Pollution-Induced Lower Respiratory Infections among Women of Childbearing Age: A Global Burden Analysis, 1990–2051

Background: Women of childbearing age (WCBA, aged 15– 49 years) represent a uniquely vulnerable population to air pollution-induced lower respiratory infections (LRIs), owing to physiological susceptibility, socioeconomic disparities, and disproportionate exposure to household air pollution. Accordingly, this study aims to characterize the epidemiological trends of air pollution-related LRIs among WCBA and elucidate the demographic and socioeconomic drivers underlying their unique vulnerability to these infections. Methods: Using Global Burden of Disease (GBD) 2021, we applied decomposition analysis, Extreme Gradient Boosting-SHapley Additive exPlanations (XGBoost-SHAP), age-period-cohort (APC), and health inequality analysis to quantify burden determinants and disparities, with Bayesian APC projections to 2051. Results: Population growth primarily drove age-standardized mortality rates (ASMR) and disability-adjusted life year (DALY) rates globally, while epidemiological shifts dominated in high socio-demographic index (SDI) regions. APC analysis revealed death risk peaked at ages 45– 49 (relative risk RR=2.24 for ambient pollution; RR=1.40 for household) and declined in post-1975 cohorts. Air pollution dominated LRIs mortality in WCBA, while location governed their DALYs. Lower SDI strengthened pollution impacts, with higher age correlating with greater risk. Health inequalities widened, with concentration indices increasing 43.8%. Projections forecast a 61.5% ASMR decline for ambient pollution-associated LRIs by 2051. Conclusion: Both ambient and household air pollution-related LRIs impose substantial, inequitable burdens on WCBA driven by demographic and socioeconomic factors. Ambient pollution dominates mortality, while location and SDI govern DALYs disparities. Health inequalities have widened significantly over three decades. Although projections indicate a 61.5% decline in ambient pollution-related ASMR by 2051, household pollution-related burdens are expected to decline more slowly. Urgent targeted interventions—particularly clean energy access in low-SDI regions and precision prevention in high-SDI areas—remain critical to address persistent health inequalities and meet global burden reduction targets. These findings provide critical evidence for shaping global health policies and achieving health equity for WCBA worldwide. Keywords: global burden of disease, air pollution, lower respiratory infections, women of childbearing age