In recent years, the incidence of colorectal cancer has been on the rise in low- and middle-income countries. Early-onset colorectal cancer (EOCRC), defined as colorectal cancer occurring in patients under 50 years of age, continues to see an increasing incidence. However, there is currently a lack of relevant epidemiological trends, which may hinder precise prevention, control strategies, and resource allocation for EOCRC.

To analyze the trends in the disease burden of EOCRC and the major risk factors for EOCRC in China and Global across different genders from 1990 to 2021 and predict the incidence and mortality rates of EOCRC for different genders in China and global from 2022 to 2046.

The incidence, mortality and disability adjusted life year (DALY) rate of colorectal cancer diagnosed between the ages of 14 and 49 in China and Global from 1990 to 2021 were collected using the Global Burden of Disease Database 2021. Age-standardized incidence rates (ASIR), age-standardized mortality rates (ASMR), and age-standardized disability-adjusted life years (ASDR) were utilized to analyze the disease burden of EOCRC and its major risk factors by gender in China and global. The Joinpoint model was used to calculate the annual percentage change (APC) and the average annual percentage change (AAPC) to reflect the trends in disease burden changes. Furthermore, the Bayesian age-period-cohort (BAPC) model was used to predict the incidence and mortality rates of EOCRC for different genders in China and globally from 2022 to 2046.

In 2021, the ASIR, ASMR, ASDR for Chinese males in EOCRC were 13.39/100 000, 4.26/100 000, 220.59/100 000, the ASIR, ASMR, ASDR for Chinese females in EOCRC in were 5.75/100 000, 1.68/100 000, 87.29/100 000. In 2021, the ASIR, ASMR, ASDR for global males in EOCRC were 6.11/100 000, 2.29/100 000, and 115.58/100 000, the ASIR, ASMR, ASDR for Chinese females in EOCRC were 4.17/100 000, 1.57/100 000, and 79.49/100 000. The AAPC for ASIR of males in China and global was 2.09% (95%CI=1.76%-2.43%) and 0.73% (95%CI=0.61%-0.84%), while for females in China, it was 0.31% (95%CI=0.04%-0.59%), all indicating an upward trend (P<0.05). The AAPC for the ASMR for males in China and global was -0.28% (95%CI=-0.51% to -0.05%) and -0.54% (95%CI=-0.68% to -0.40%), the AAPC was -2.22% (95%CI=-2.47% to -1.97%) in Chinese female and -1.25% (95%CI=-1.37% to -1.13%) in global female, all indicating a downward trend (P<0.05). The trend of ASIR trend for global females exhibited fluctuations, with AAPC of -0.09% (95%CI=-0.22% to 0.04%) (P>0.05). The trend of ASDR for Chinese male showed an inverted "V" shape, with AAPC of -0.20% (95%CI=-0.45% to 0.04%) (P>0.05). By 2046, the predicted ASIR and ASMR for Chinese male are expected to be 28.46/100 000 and 4.80/100 000. For females in China, these rates are projected to be 7.41/100 000 and 1.23/100 000. Globally, the ASIR and ASMR for males are forecasted to be 5.90/100 000 and 1.62/100 000, while for females, the rates are expected to be 3.06/100 000 and 1.05/100 000.

The disease burden of EOCRC in both males and females in China is severe and exceeds the global average, exhibiting significant gender disparities. There is a need to deepen the focus on the gender disparities associated with EOCRC and to implement targeted prevention and control measures. Additionally, drawing on global prevention and treatment experiences can provide a valuable reference for policy formulation.

近年来，结直肠癌（CRC）在低、中等收入国家发病率呈上升趋势，其中50岁以下的CRC患者，即早发型结直肠癌（EOCRC），发病率持续上升，但目前缺乏相关流行病学趋势分析，可能一定程度上阻碍了对该疾病的精准防控与医疗资源分配。

分析1990—2021年中国及全球不同性别的EOCRC疾病负担趋势及主要危险因素，预测2022—2046年我国及全球不同性别的EOCRC发病、死亡情况。

基于2021年全球疾病负担研究（GBD 2021），收集1990—2021年中国和全球15~49岁人群CRC数据，采用标化发病率（ASIR）、标化死亡率（ASMR）、标化伤残调整寿命年（ASDR）分析我国及全球不同性别EOCRC疾病负担情况及主要危险因素。采用Joinpoint模型计算年度变化百分比（APC）和平均年度变化百分比（AAPC）分析疾病负担变化趋势。使用贝叶斯年龄-时期-队列（BAPC）模型预测2022—2046年我国及全球不同性别EOCRC发病及死亡情况。

2021年中国男性EOCRC的ASIR、ASMR和ASDR分别为13.39/10万、4.26/10万、220.59/10万，女性为5.75/10万、1.70/10万、87.29/10万；全球男性水平分别为6.11/10万、2.29/10万、115.58/10万，女性为4.17/10万、1.57/10万、79.49/10万。我国及全球男性、我国女性ASIR的AAPC分别为2.09%（95%CI=1.76%~2.43%）、0.73%（95%CI=0.61%~0.84%）、0.31%（95%CI=0.04%~0.59%），均呈上升趋势（P<0.05）。我国及全球男性、我国及全球女性ASMR的AAPC分别为-0.28%（95%CI=-0.51%~-0.05%）、-0.54%（95%CI=-0.68%~-0.40%）、-2.22%（95%CI=-2.47%~-1.97%）、-1.25%（95%CI=-1.37%~-1.13%），均呈下降趋势（P<0.05）。全球男性、我国及全球女性ASDR的AAPC分别为-0.51%（95%CI=-0.69%~-0.32%）、-2.10%（95%CI=-2.33%~-1.87%）、-1.24%（95%CI=-1.36%~-1.11%），均呈下降趋势（P<0.05）。全球女性ASIR趋势波折，AAPC为-0.09%（95%CI=-0.22%~0.04%）（P>0.05），我国男性ASDR趋势呈倒"V"字形，AAPC为-0.20%（95%CI=-0.45%~0.04%）（P>0.05）。预测到2046年，我国男性ASIR、ASMR为30.29/10万、5.10/10万，女性为8.75/10万、1.46/10万；全球男性为6.36/10万、1.75/10万，女性为3.43/10万、1.18/10万。

我国男女EOCRC疾病负担形势严峻且高于全球水平，具有明显的性别差异，可加强对EOCRC性别差异的关注，开展性别精准防控，同时借鉴全球防治经验，为制定政策提供参考依据。