Abstract
BACKGROUND AND AIMS: Colorectal cancer (CRC) is a major global health concern, with rising early-onset cases (EOCRC) among adolescents and young adults (AYAs, 15-39 years). This study evaluates the global burden, trends, and risk factors of AYA CRC from 1990 to 2021 using Global Burden of Disease (GBD) 2021 data. METHODS: Utilizing GBD 2021 estimates, we analyzed incidence, prevalence, mortality, disability-adjusted life years (DALYs), and attributable risk factors. To analyze temporal trends, we employed joinpoint regression with a maximum of four nodes, and future burden projections were generated using ARIMA models. Analyses were stratified by age, sex, region, and Socio-Demographic Index (SDI). RESULTS: Global AYA CRC incidence rose from 41,384 cases in 1990 to 70,201 in 2021 (AAPC: 0.35), with the highest age-standardized incidence rate (ASIR) in East Asia (5.11 per 100,000). Mortality decreased (AAPC: -1.00), driven by improved healthcare, while prevalence increased. Low whole-grain intake (15.9% DALYs) and high red meat consumption (12.7%) dominated globally, while high BMI emerged as a growing contributor, particularly in high-SDI regions. Males had higher burden than females, peaking at ages 35-39. By 2060, the ASIR is projected to rise by 14.7%, with the most pronounced increases in low-middle SDI regions, where healthcare infrastructure remains underdeveloped. CONCLUSION: The rising incidence of AYA CRC underscores urgent needs for targeted prevention, early screening, and lifestyle interventions addressing modifiable risks like diet and obesity. Geographic and socioeconomic disparities highlight the importance of equitable healthcare access to mitigate future burden.