Global burden of colorectal cancer and associated risk factors in young-older adults: Trends from 1990 to 2021 with projections to 2050.

Colorectal cancer (CRC) poses a significant global health challenge, yet the disease burden and epidemiological trends in young-older adults (65-74 years) remain poorly understood. This age group warrants special attention because it experiences peak disease incidence while maintaining relatively preserved functional capacity and better tolerance to therapy compared with individuals aged ≥75 years. Data from the Global Burden of Disease 2021 were used to assess the CRC burden in individuals aged 65 to 74 years from 1990 to 2021. Age-standardized rates for incidence, prevalence, mortality, and disability-adjusted life years were computed, alongside temporal trend analysis via estimated annual percentage change (EAPC). We also evaluated disease burden associations with socio-demographic index, burden trends from major risk factors, and disease projections to 2050 using autoregressive integrated moving average modeling. Globally, age-standardized rates for incidence increased modestly from 125.03 per 100,000 person-years in 1990 to 136.19 per 100,000 person-years in 2021 (EAPC 0.10%, 95% confidence interval: 0.03-0.16%). Males demonstrated increasing trends (EAPC 0.39%) while females showed declining patterns (EAPC -0.36%). Middle-income countries and East Asia exhibited steepest increases (EAPC 1.68% and 1.99%), contrasting with reductions in high-income regions. Age-standardized mortality rate declined significantly from 73.41 per 100,000 person-years in 1990 to 58.48 per 100,000 person-years in 2021 (EAPC -0.96%). High-income regions achieved superior mortality improvements, particularly Australasia (EAPC -2.72%) and North America (EAPC -2.32%). Diet low in milk constituted the leading attributable risk factor in 2021. Projections indicate continued mortality decline (EAPC -0.80%) alongside persistent prevalence growth (EAPC 0.57%) through 2050. Among young-older adults, CRC burden demonstrates declining mortality alongside rising incidence and prevalence, with substantial regional inequalities. Targeted interventions addressing modifiable risk factors are essential, particularly in middle-income regions undergoing epidemiological transition.