Abstract: Objective  To explore the incidence trend of intracerebral hemorrhage in adolescents and young adults in China from 1990 to 2021, and its effects influenced by age, period, and cohort factors, aiming to provide a scientific basis for the formulation of prevention and control strategies. 
Methods  Based on global burden of disease (GBD) 2021 data, According to the relevant regulations of the World Health Organization and the National Bureau of Statistics of China, this study analyzed the incidence of intracerebral hemorrhage in adolescents and young adults aged 15-39 years in China from 1990 to 2021. Joinpoint software was used to assess the standardized incidence trend and calculate the annual percentage change as well as the average annual percentage change (AAPC). Additionally, an age-period-cohort model was used to explore the influencing factors and predict future incidence trends. 
Results  From 1990 to 2021, the overall and gender-standardized incidences of intracerebral hemorrhage in adolescents and young adults in China showed a decreasing trend (AAPC: total ﹣1.31%, males ﹣0.72%, females ﹣2.29%, P<0.001). Longitudinal data indicated that the number of cases, crude incidence, and standardized incidence were all higher in males than in females. The age-period-cohort model demonstrated that the incidence of intracerebral hemorrhage increased with age, peaking at ages 35-39 for males, and was 2.74 times higher than that of females of the same age. Furthermore, the risk of disease was lower in the 1997—2006 birth cohort (RR 0.72). It is predicted that by 2044, the standardized incidence for males will decrease by 10.01%, while for females it will increase by 3.84%. The number of cases, crude incidence, and standardized incidence in males are still 1.93-2.26 times that of females.
Conclusions  From 1990 to 2021, the incidence of intracerebral hemorrhage in adolescents and young adults in China has generally decreased, but it was higher in males than in females. Advancing age is an important risk factor for the disease, especially in males aged 35-39 years. The risk of disease is lower in recent periods and birth cohorts. It is predicted that by 2044, the incidence for males will continue to decrease, while it will slightly increase for females, but the incidence for males will still be higher than that for females. This suggests that in the future, efforts should be strengthened to prevent intracerebral hemorrhage in male adolescents and young adults and subsequently reducing the burden of the disease.

Key words: Intracerebral hemorrhage; Incidence; Trend analysis; Joinpoint regression; Age-period-cohort model

摘要： 目的 探究1990—2021年中国青少年和青年人群脑出血的发病趋势及其受年龄、时期和队列因素影响的效应，旨在为防控策略的制定提供科学依据。
方法 本研究基于2021年的全球疾病负担（global burden of disease，GBD）数据库，根据世界卫生组织和中国国家统计局的相关标准，纳入1990—2021年中国15～39岁青少年和青年人群，分析其脑出血发病情况，运用Joinpoint软件评估标化发病率趋势并计算年度变化百分比和平均年度变化百分比（average annual percentage change，AAPC），同时采用年龄-时期-队列模型探讨影响因素并预测未来发病趋势。
结果 1990—2021年，中国青少年和青年人群脑出血总人群及分性别标化发病率均呈下降趋势（AAPC：总体﹣1.31%，男性﹣0.72%，女性﹣2.29%，P<0.001）。历年数据显示，男性的发病数、粗发病率和标化发病率均高于女性。年龄-时期-队列模型揭示，脑出血发病率随年龄增长而上升，男性在35～39岁时达到峰值，为同龄女性的2.74倍。此外，1997—2006年的出生队列的发病风险较低（RR 0.72）。预测至2044年，男性标化发病率将下降10.01%，而女性将上升3.84%，男性在发病数、粗发病率和标化发病率上仍为女性的1.93～2.26倍。
结论 1990—2021年中国青少年和青年人群脑出血发病率总体下降，但男性高于女性。年龄增长是发病的重要风险因素，尤其在35～39岁男性中最高，晚近时期和出生队列的发病风险较低。预测至2044年，男性发病率继续下降，女性略上升，但男性发病率仍高于女性。提示未来需加强男性青少年和青年人群脑出血的预防，进而降低疾病负担。

关键词: 脑出血; 发病率; 趋势分析; Joinpoint回归; 年龄-时期-队列模型