Age⁃period⁃cohort model and decomposition analysis of colorectal cancer mortality trends in China and the United States from 1992 to 2021

ObjectiveTo compare the long⁃term trends in colorectal cancer(CRC) mortality rates in China and the United States(U.S.) from 1992 to 2021 and to provide scientific evidence for CRC prevention and control in China.MethodsBased on data from the GBD2021 database,CRC mortality burden data for China and the U.S.from 1992 to 2021 were extracted.The Age⁃Period⁃Cohort(APC) model was used to evaluate the independent effects of age,period,and cohort,while decomposition analysis quantified the contributions of aging,population growth,and epidemiological changes to CRC mortality.ResultsFrom 1992 to 2021,colorectal cancer deaths increased in both China and the United States.However,the age⁃standardized mortality rate(ASMR) declined in both countries,with males consistently bearing a higher mortality burden than females.According to the age⁃period⁃cohort(APC) model,colorectal cancer mortality rose sharply with age in both countries,particularly among individuals aged 50 years and older.In China,the overall mortality rate increased from 0.53 per 100 000 to 236.50 per 100 000,while in the United States it rose from 0.11 per 100 000 to 171.02 per 100 000. The period effect demonstrated a downward trend in both countries,with the period rate ratio decreasing from 1.10 to 0.91 in China and from 1.07 to 0.85 in the United States.The cohort effect also showed a continuous decline,with China's cohort rate ratio decreasing from 1.34 to 0.46 and the U.S.declining from 2.54 to 0.74.Although the U.S.exhibited higher cohort risks,its reduction was more pronounced.Decomposition analysis further indicated that the rise in colorectal cancer deaths in China was primarily driven by population aging and population growth,whereas the mortality changes in the United States were predominantly attributable to improvements in epidemiological factors.ConclusionsFrom 1992 to 2021,the ASMR for CRC declined in both China and the U.S.;however,CRC mortality changes in China were primarily driven by aging and population growth,highlighting the need for enhanced screening and intervention for older males.Epidemiological improvements had more pronounced effect in the U.S.,emphasizing the need for China to strengthen CRC prevention and screening efforts for the aging population and further to improve the impact of epidemiological changes.