S2481 Clean Air, Higher Mortality? A Paradoxical Trend in Liver-Related Deaths Across US States: A Longitudinal Analysis Using CDC WONDER and EPA AQS Databases (2004-2023)

Introduction: Air pollution has been implicated in hepatic inflammation and progression of chronic liver diseases. However, real world data on the impact of ambient air quality on liver related mortality is sparse. This study examines the relationship between air quality and liver mortality among older adults across U.S. states from 2004 to 2023. Methods: Non-infectious liver related crude death rates (per 100,000) of age group 45-54 years were obtained from the CDC WONDER Multiple Cause of Death database. Median annual Air Quality Index (AQI) data were retrieved from the U.S. EPA AQS database. Data sets were refined, organized and merged by state and year. We performed correlation (Pearson and Spearman) and linear regression analyses to assess associations. States were stratified by AQI into highest 10 (worst air quality) and lowest 10 (best air quality). Non-parametric tests (Mann-Whitney U) were used to compare mortality differences across AQI strata. Results: Contrary to expectations, median AQI was negatively correlated with liver-related mortality (Pearson r = -0.17, P < 0.0001). Linear regression showed each unit increase in AQI was associated with a 0.29 decrease in crude liver death rate (β = -0.29, P < 0.0001; R² = 0.03). States with the worst AQI (e.g., California, Delaware) had lower average mortality (mean = 29.88/100,000), while the cleanest-air states (e.g., Montana, Hawaii) had higher mortality (mean = 36.33/100,000). The mortality difference between AQI groups was statistically significant (P < 0.001) and this inverse pattern persists for many years. Conclusion: This study reveals a paradoxical inverse association between air pollution and liver-related mortality across the states. This trend highlights the strong influence of unmeasured confounders such as healthcare access, substance use patterns and urban vs rural disparities. These findings raise critical questions for aging population making residential decisions based on perceived air pollution levels and environmental quality.