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.