Persistent disparities despite declining carbon monoxide mortality in the United States: a nationwide analysis, 1999-2023.

Background: Carbon monoxide (CO) poisoning remains a preventable cause of mortality. However, emerging evidence suggests that recent progress in prevention may not be equitably experienced across the population groups in the United States. Long-term national assessments of disparities in CO mortality are inadequate. Objectives: This study sought to identify trends in CO poisoning mortality, assess disparities, and inform future studies. Methods: We conducted a descriptive epidemiological study, using national mortality data from the Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research (CDC WONDER) for 1999-2023. The study population included adults aged 25 years and older, with 47,160 deaths identified. Age-adjusted mortality rates were calculated, and trends were assessed using joinpoint regression to estimate annual and average annual percent change (APC and AAPC), with 95% confidence intervals (CIs). Analyses were stratified by sex, race and ethnicity, age group, geographic region and urban-rural status. All analyses represent primary use of these data. Results: National age-standardized mortality declined over the study period (AAPC -3.02%; 95% CI - 4.58 to -1.43), but the decline slowed after 2010. Mortality among Hispanic adults increased substantially after 2016, with signs of trend reversal among non-Hispanic Black adults. Mortality in non-metropolitan areas remained approximately 1.8 times higher than in metropolitan areas, with evidence suggesting that prior declines may have stalled. Conclusion: Declines in CO poisoning mortality have slowed in the United States, with some evidence of recurrent annual fluctuations, accompanied by widening racial, ethnic, and geographic differences.