Colorectal cancer burden, trends, and risk factors in China: rising incidence and disparities in the last 3 decades

Background: Colorectal cancer (CRC) ranks as the fourth leading cause of cancer-related deaths in China. With the recent rise in CRC incidence rates nationally, having the most current data on CRC burden, trends, and risk factors is essential for informing screening, early detection, and treatment efforts. This information can also aid in the effective allocation of resources. This study sought to examine the burden, trends, and risk factors of CRC in China from 1990 to 2021. Methods: The Global Burden of Disease (GBD) study is the most extensive global observational epidemiological study to date. Covering trends from 1990 to 2021, the latest GBD report provides data on mortality and morbidity across 204 countries and territories, encompassing 371 diseases and injuries and 88 risk factors. For this study, we extracted data from GBD 2021, including incidence, deaths, and disability-adjusted life years (DALYs) associated with CRC in China. GBD 2021 calculated the disease burden of CRC using a comparative risk assessment (CRA) framework. Risk factors in the GBD study are categorized into four levels, with Level 1 being the broadest and Level 4 the most specific. Due to data limitations, this study obtained data on the CRC-related Level 3 risk factor groups. Findings: From 1990 to 2021, the age-standardized incidence rate (ASIR) rose from 19.04 per 100,000 to 31.44 per 100,000 (average annual percent change, AAPC: 0.65), while the age-standardized mortality rate (ASMR) fell from 15.49 per 100,000 to 13.64 per 100,000 (AAPC: -0.12), resulting in a decline in age-standardized DALYs (ASDALYs) from 390.63 per 100,000 in 1990 to 331.73 per 100,000 in 2021 (AAPC: -0.15). Furthermore, the ASIR, ASMR, and ASDALYs among males were higher than among females from 1990 to 2021. AAPCs for ASIR, ASMR, and ASDALYs were 0.89, 0.02, and 0 in males, compared to 0.33, -0.29, and -0.34 in females, indicating a widening sex disparity. Notably, AAPCs for ASIR, ASMR, and ASDALYs among those aged 20-54 were 1.27, 0.09, and 0.06, respectively, while those aged 55 and over had values of 0.83, 0.02, and -0.07, respectively. Leading risk factors contributing to CRC mortality included low milk and low whole grain intake, accounting for 18.53% and 18.09%, respectively. Interpretation: This study revealed that the burden of CRC in China continued to evolve, with rising incidence rates and disparities between sexes and age groups. The widening gap between male and female CRC outcomes highlighted the need for sex-specific strategies in prevention and treatment. Additionally, the increasing ASIR, ASMR, and ASDALYs among younger individuals suggested that screening efforts should begin earlier to address this shift given that most guidelines in China still recommend that screening for CRC starts from age 50 years. The identification of dietary risk factors, particularly low milk and whole grain intake, called for public health campaigns to promote healthier eating habits as part of a comprehensive approach to CRC prevention. Overall, the findings emphasized the need for tailored CRC screening, prevention, and resource allocation strategies to reduce the burden and improve long-term outcomes across diverse populations.