Background: Early-onset colorectal cancer (EOCRC), defined as a diagnosis between ages 15 and 49 years, has shown a rapid increase in incidence worldwide and displays distinct clinical and molecular features compared with later-onset disease.
Objectives: This study aimed to comprehensively assess the global, Chinese, and U.S. burden of EOCRC from 1990 to 2021, quantify the contribution of major modifiable risk factors, and forecast trends in age-standardized incidence, mortality, and disability-adjusted life years (DALYs) rates through 2040.
Methods: Data were obtained from the Global Burden of Disease (GBD) 2021 database. Age-standardized incidence rate (ASIR), mortality rate (ASMR), and DALY rate(s) were estimated using direct standardization. Temporal trends (1990–2021) were evaluated with Joinpoint regression to derive annual percentage change (APC) and average annual percentage change (AAPC). Sex-specific and regional variations were analyzed for China, the United States, and the global population. Attributable fractions quantified the impact of dietary, lifestyle, and metabolic risk factors. The Bayesian age–period–cohort (BAPC) model was used to project EOCRC burden through 2040.
Results: In 2021, an estimated 211,900 new EOCRC cases occurred globally, corresponding to an ASIR of 5.37 per 100,000, along with 79,500 deaths and a total of 4.00 million DALYs lost. China experienced a substantially higher burden than the global average, with an ASIR of 10.02 per 100,000, an ASMR of 3.11 per 100,000, and an age-standardized DALY rate of 160.93 per 100,000, disproportionately affecting males. The United States had a higher ASIR than China (11.97 vs. 10.02 per 100,000) but exhibited lower ASMR and age-standardized DALY rates. From 1990 to 2021, ASIRs increased globally (AAPC= 0.374) and more markedly in China (AAPC= 1.423), whereas ASMR (AAPC= −0.855) and DALY rates (AAPC= −0.834) declined. In China, ASMR and DALY rates declined overall but rebounded in recent years, whereas in the United States, ASIR began to decrease after 2017, while ASMR and DALY rates remained relatively stable. By sex, China’s male ASIR increased by 89.7% between 1990 and 2021, with rises also observed in ASMR and DALY rates in recent years. Regarding risk factors, insufficient whole-grain intake and excessive red meat consumption emerged as the leading modifiable contributors to EOCRC mortality and DALYs globally and in both countries, accounting for 33.34% and 32.90% of the global burden, respectively. Heavy alcohol consumption and tobacco use were particularly significant contributors among Chinese men. Projections indicated that China’s ASIR is projected to rise to 17.04 per 100,000 by 2040, whereas the United States is expected to maintain a downward trend.
Conclusions: The burden of EOCRC has risen sharply in the past three decades, with China experiencing the steepest increase and highest burden compared with the United States and the global average. Targeted prevention is urgently needed, emphasizing dietary improvements and stricter tobacco and alcohol control. Lowering the colorectal cancer screening age in high-risk Chinese populations and integrating screening, treatment, and follow-up could mitigate this growing burden and improve outcomes.

Burden of Early-Onset Colorectal Cancer: A Global, China, and USA Projection, 2022-2040