Early-Onset Colorectal Cancer Mortality Trends across the U.S. Rural-Urban Continuum, 1999-2020: A Population-Based Ecological Study

Abstract

Background/Objectives: Early-onset colorectal cancer (EOCRC) mortality has increased among younger adults in the United States, while rural-urban disparities in colorectal cancer outcomes remain persistent. This study evaluated EOCRC mortality trends among adults aged 25 - 44 years from 1999 to 2020 across the U.S. rural-urban continuum. Methods: We conducted a retrospective, population-based ecological study using the CDC WONDER Underlying Cause of Death database. Deaths were identified using ICD-10 codes C18-C20 for colorectal cancer as the underlying cause of death. Age-adjusted mortality rates (AAMRs) per 100,000 population were standardized to the 2000 U.S. standard population and stratified by 2013 National Center for Health Statistics urban-rural classification categories. Temporal trends were assessed using joinpoint regression to estimate annual percent change and average annual percent change (AAPC). Results: From 1999 to 2020, 37,459 EOCRC deaths occurred among U.S. adults aged 25 - 44 years. National AAMRs increased from 2.0 to 2.4 per 100,000, corresponding to an AAPC of +0.79% per year (95% CI: 0.63 - 0.95; p Conclusions: EOCRC mortality increased steadily across the U.S. rural-urban continuum, with persistently higher absolute mortality in nonmetropolitan populations. These findings support geographically targeted strategies to improve early detection, screening access, and colorectal cancer outcomes among younger adults.