Empowering Youth to Build the Families They Want: Opportunities and Challenges

Danan Gu^1,#

1. Population Division, Department of Economic and Social Affairs, United Nations, New York, USA.

^# Corresponding author: Danan Gu, gud@un.org.

World Population Day 2025, themed “Empowering young people to create the families they want in a fair and hopeful world,” highlights youth’s right to reproductive autonomy and their vital role in shaping demographic futures. With nearly 2 billion young people worldwide, many face persistent barriers to realizing their family aspirations, ranging from limited access to sexual and reproductive health services and quality education, to gender inequality, economic insecurity, and digital exclusion. This brief highlights how these challenges impact youth, particularly in low- and middle-income countries, and calls for inclusive, rights-based solutions. Key priorities include youth-responsive health and education systems, stronger labor protections and social supports, and greater digital and climate access. Achieving these goals requires global solidarity, sustained investment, and meaningful youth participation. The brief argues that empowering young people is not only a moral imperative but also essential to unlocking demographic potential and building a more just, inclusive, and resilient future for all.

赋能青年创建理想家庭：机遇与挑战

顾大男^1,#

1. 人口司，经济和社会事务部，联合国，纽约，美国。

^# 通信作者: 顾大男，gud@un.org。

2025年世界人口日的主题为“赋能青年，在公平与希望中创建他们想要的家庭”，强调了青年在实现生育自主权方面的权利，以及他们在塑造人口未来中的关键作用。全球近20亿青年中，许多人在实现家庭愿望的道路上面临持续障碍，这些障碍包括获得性与生殖健康服务和优质教育的机会有限、性别不平等、经济不安全以及数字鸿沟等问题。本简报指出，这些挑战如何影响青年，尤其是在中低收入国家的青年，并呼吁采取包容性、以权利为基础的解决方案。重点优先领域包括适应青年的卫生和教育体系、更强有力的劳动保护与社会支持，以及更广泛的数字和气候资源获取。实现这些目标需要全球团结、持续投入和青年参与的实质性加强。本简报主张，赋能青年不仅是道义上的责任，更是释放人口潜力、建设更加公正、包容和有韧性的未来的关键所在。

For more information: https://weekly.chinacdc.cn/en/article/doi/10.46234/ccdcw2025.159

Trends in the Incidence, Mortality and Lifetime Risks of Female Breast and Cervical Cancer — Guangdong Province, China, 2023

Yu Liao^1,&; Qian Zhu^2,&; Kexin Sun²; Rongshou Zheng²; Huihong Deng¹; Lifeng Lin¹; Ruilin Meng¹; Wenqiang Wei^2,#; Ye Wang^1,#

1. Guangdong Provincial Center for Disease Control and Prevention, Guangzhou City, Guangdong Province, China;

2. Office for Cancer Registry, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.

^& Joint first authors.

^# Corresponding author: Ye Wang, sjkzx_mfs@gd.gov.cn; Wenqiang Wei, weiwq@cicams.ac.cn.

This study aims to report the epidemiological trends and provide updated estimates and lifetime risks for breast and cervical cancers among women in Guangdong Province. A Bayesian age-period-cohort model was applied to project incidence and mortality rates for 2023. The adjusted for multiple primaries (AMP) method was used to calculate the lifetime risks of developing and dying from breast and cervical cancer. Joinpoint analysis was employed to describe the temporal trends. The age-standardized incidence rate (ASIR) of female breast cancer increased from 2012 to 2019 in Guangdong Province, with a particularly pronounced increase noted in the rural areas. The ASIR for cervical cancer among women aged over 55 increased in both urban and rural areas, whereas a declining trend was observed among women under the age of 55. The age-standardized mortality rates (ASMRs) for both breast cancer and cervical cancer demonstrated upward trends among women aged over 55, while no significant trend in ASMR was found for women under 55 years. In 2023, the estimated incidence rates of breast cancer and cervical cancer would be 50.81/10⁵ (ASIR would be 35.57/10⁵) and 15.31/10⁵ (ASIR would be 10.41/10⁵) respectively, with corresponding mortality rates of 10.78/10⁵ (ASMR would be 7.15/10⁵) and 6.11/10⁵ (ASMR would be 3.93/10⁵) for these cancers. Breast cancer continues to pose a significant threat to women's health in both rural and urban areas of Guangdong, whereas cancer prevention and control programs for cervical cancer have shown positive impacts among the younger population. Greater emphasis should be placed on women aged over 55 to halt the rising mortality rates of both cancers within this population.

女性乳腺癌和宫颈癌发病及死亡终身风险分析和流行趋势研究 — 广东省，中国，2023年

廖羽^1,&；朱倩^2,&；孙可欣²；郑荣寿²；邓惠鸿¹；林立丰¹；孟瑞琳¹；魏文强^2,#；王晔^1,#

1. 广东省疾病预防控制中心，广州市，广东省，中国；

2. 肿瘤登记办公室，国家癌症中心/国家肿瘤临床医学研究中心，中国医学科学院北京协和医学院肿瘤医院，北京市，中国。

^& 共同第一作者。

^# 通信作者: 王晔，sjkzx_mfs@gd.gov.cn；魏文强，weiwq@cicams.ac.cn。

本研究旨在分析广东省女性乳腺癌和宫颈癌的流行趋势，并进行全省发病、死亡估计及终身风险分析。采用贝叶斯年龄-时期-队列模型预测2023年发病和死亡情况。通过多原发肿瘤调整法计算乳腺癌和宫颈癌的终身发病风险和死亡风险。采用Joinpoint分析描述疾病流行的时间趋势。2012至2019年期间，广东省女性乳腺癌的年龄标化发病率呈上升趋势，农村地区尤为显著。对于宫颈癌，城乡地区55岁以上女性的年龄标化发病率均有所上升，而55岁以下女性则呈下降趋势。乳腺癌和宫颈癌的年龄标化死亡率在55岁以上女性中均呈上升趋势，而在55岁以下女性中变化趋势无统计学意义。2023年广东省乳腺癌和宫颈癌估计发病率分别为50.81/10万（年龄标化发病率为35.57/10万）和15.31/10万（年龄标化发病率为10.41/10万），相应死亡率分别为10.78/10万（年龄标化死亡率为7.15/10万）和6.11/10万（年龄标化死亡率为3.93/10万）。乳腺癌仍是威胁广东省城乡女性健康的重要疾病；而趋势分析显示针对宫颈癌的防控措施已在年轻人群中显示出积极效果。应更加重点关注55岁以上女性群体，遏制该群体中两癌死亡率的上升趋势。

For more information: https://weekly.chinacdc.cn/en/article/doi/10.46234/ccdcw2025.157

Cost-Effectiveness of Increasing Outdoor Activity in Preventing Myopia in Children and Adolescents — China

Bonan Fan^1,&;  Xuanjing Li^2,&;  Yipeng Lyu¹;  Xiang Gao¹;  Shan Zhao¹;  Stella Wong³;  Xinyi Liu^2,#;  Yan Li^1,4,#

1. School of Public Health, Shanghai Jiao Tong University, Shanghai, China;

2. School of Medicine, Shanghai Jiao Tong University, Shanghai, China;

3. School of Public Health, Imperial College London, London, UK;

4. Department of Population Health Science and Policy, Icahn School of Medicine at Mount Sinai, New York, NY, USA.

^& Joint first authors.

^# Corresponding author: Xinyi Liu, xinyi_liu@sjtu.edu.cn; Yan Li, yan.li1@mountsinai.org.

Myopia has emerged as a major public health challenge affecting the visual health of children and adolescents in China. While evidence confirms the effectiveness of outdoor activity in preventing myopia, comprehensive economic analyses of its role in mitigating myopia-related diseases remain limited. This study employed a Markov model to evaluate the cost-effectiveness of increasing outdoor activity across different educational stages — primary, middle, and high school — for myopia prevention in China. The model simulated myopia progression among individuals aged 6 to 18 years, with the intervention defined as an additional 40 minutes of daily outdoor activity. Outcomes measured included changes in myopia prevalence, quality-adjusted life years (QALYs), and associated medical costs. All intervention scenarios proved cost-effective, except for those targeting only the high school stage. Interventions focused on primary schools and combined primary–middle school stages not only improved health outcomes but also reduced medical costs. While the all-stages intervention yielded the greatest health benefits, its higher implementation costs make it more suitable for regions with greater resources. These findings highlight the critical importance of early intervention in myopia prevention. Policymakers should prioritize outdoor activity programs at the primary school level and develop tailored prevention strategies based on local resource availability. This study provides empirical evidence for developing scientifically sound, cost-effective myopia prevention strategies for children and adolescents, with relevant implications for other developing countries facing high myopia burden.

儿童和青少年增加户外活动预防近视的成本效果分析 — 中国

范伯男^1,&；李宣静^2,&；吕奕鹏¹；高翔¹；赵珊¹；Stella Wong³；刘心怡^2,#；李岩^1,4,#

1. 公共卫生学院，上海交通大学，上海，中国

2. 医学院，上海交通大学，上海，中国

3. 公共卫生学院，帝国理工学院，伦敦，英国

4. 人口健康科学与政策系，西奈山伊坎医学院，纽约市，纽约州，美国

^& 共同第一作者。

^# 通信作者：刘心怡，xinyi_liu@sjtu.edu.cn；李岩，yan.li1@mountsinai.org。

近年来，中国儿童青少年近视问题已经成为影响国民眼健康的重大的公共卫生挑战。已有研究证实了户外活动在预防儿童和青少年近视方面具有明确效果，但对于该策略的经济价值尚缺乏系统评估。本研究基于马尔可夫模型，评估了在中国不同学段（小学、初中、高中）实施增加户外活动干预措施预防近视的成本效果。模型模拟了6至18岁人群的近视进展进程，以每日增加40分钟户外活动作为干预方案，测算干预对近视患病率、质量调整生命年（QALYs）及医疗成本的影响。除高中阶段外，所有干预方案均为成本效果较高的策略，其中小学及小学-初中联合干预在节约医疗成本的同时提升健康效益；尽管覆盖所有学段的干预可获得最大健康收益，但其实施成本较高，更适宜资源充足的地区。研究结果揭示早期干预是控制近视进展的关键，建议政策制定者优先在小学阶段推广户外活动干预，并因地制宜制定精准的防控策略。本研究为制定科学、经济可行的青少年近视防控策略提供了实证依据，亦对其他近视高发的发展中国家具有参考价值。

For more information: https://weekly.chinacdc.cn/en/article/doi/10.46234/ccdcw2025.158

Establishment and Validation of a Risk Prediction Model for Non-Suicidal Self-Injury Among Adolescents Based on Machine Learning Methods — Jiangsu Province, China, 2023

Xin Wang¹; Yan Wang¹; Jiawen Tang²; Yang Wang³; Ran Zhang³; Xiyan Zhang¹; Wenyi Yang¹; Wei Du⁴; Fei Wang^3,#; Jie Yang^1,#

1. Department of Child and Adolescent Health Promotion, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing City, Jiangsu Province, China;

2. School of Public Health, Nanjing Medical University, Nanjing City, Jiangsu Province, China;

3. Early Intervention Unit, Department of Psychiatry, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing City, Jiangsu Province, China;

4. School of Public Health, Southeast University, Nanjing City, Jiangsu Province, China.

^# Corresponding author: Jie Yang, july-summer@jscdc.cn; Fei Wang, fei.wang@yale.edu.

Non-suicidal self-injury (NSSI) is becoming increasingly prevalent among adolescents, posing a significant public health challenge with profound implications for both physical and mental well-being. This study investigates the prevalence of NSSI among adolescents in Jiangsu Province and develops a risk prediction model to support early detection and intervention. This study was based on the baseline cross-sectional data from the longitudinal cohort study "School-based Evaluation and Response to Child Health (SEARCH)". In 2023, a stratified cluster randomized sampling method was used to recruit students from 11 schools in Jiangsu Province, China. Following data cleaning, 11,427 students were included in the analysis, and a machine learning-based risk prediction model for adolescent NSSI was constructed. 12.72% of adolescents aged 10-18 had undergone NSSI.  Eight key predictors of NSSI were identified: insomnia, emotional symptoms, cohesion of family environment, history of drinking alcohol, gender, conflict of family environment, conduct problems, and academic level. In the test set, the XGBoost model demonstrated an area under the curve (AUC) of 0.800 (95% confidence interval: 0.776-0.823) and an accuracy (ACC) of 0.886. This study underscores the critical importance of personalized prevention strategies for NSSI and highlights the need for comprehensive behavioral interventions, such as enhancing mental health support, improving sleep quality, and fostering supportive family environments.

基于机器学习方法建立并验证青少年非自杀性自伤风险预测模型—江苏省，中国，2023 年

王欣¹; 王艳¹; 汤佳雯²; 王洋³; 张然³; 张锡彦¹; 杨文漪¹; 杜伟⁴;王菲^3,#;杨婕^1,#

1.江苏省疾病预防控制中心儿童青少年健康促进所，南京市，江苏省，中国；

2.南京医科大学公共卫生学院，南京市，江苏省，中国；

3.南京医科大学附属脑科医院早期干预科, 南京市，江苏省，中国；

4.东南大学公共卫生学院，南京市，江苏省，中国。

^# 通信作者：杨婕, july-summer@jscdc.cn; 王菲, fei.wang@yale.edu。

非自杀性自伤（NSSI）在青少年群体中愈发常见，已成为一个对身心健康皆有显著影响的重大公共卫生问题。本研究旨在阐述江苏省青少年中非自杀性自伤的检出率，并构建一个风险预测模型以助力早期识别与干预NSSI。本研究依托“学校健康促进评估项目（SEARCH）”项目展开。2023 年，对中国江苏省 11 所学校的学生进行了横断面调查。经数据清理后，11,427 名学生被纳入分析，运用机器学习方法构建了青少年 NSSI 的风险预测模型。10 - 18 岁的青少年中，12.72% 有过 NSSI 经历，同时明确了NSSI的八大主要预测因素，涵盖失眠、情绪症状、家庭环境亲密性、饮酒史、性别、家庭环境冲突性、行为问题及学段。在测试集中，XGBoost模型的曲线下面积（AUC）和准确率（ACC）分别为 0.800（95%置信区间：0.776 - 0.823）和 0.886。本研究凸显了个性化防自伤策略的重要性，同时强调了实施诸如提供心理健康支持、提升睡眠质量以及营造支持性家庭环境等综合行为干预措施的必要性。

For more information: https://weekly.chinacdc.cn/en/article/doi/10.46234/ccdcw2025.160