Abstract:
Background　In the last several decades，the Chinese Government has made substantial progress in reducing under-five mortality rate（U5MR），but the disparity in U5MR between urban and rural areas still exists. Objective　To identify the main causes of death and potential years of life lost among children under 5 years old across different regions of Yunnan Province from 2015 to 2019. Methods　According to the poverty headcount ratio in 2017，a total of 129 districts and counties in Yunnan were categorized into severely impoverished，poor，and non-poor areas. Data about reported death among children under 5 years old in these areas during 2015—2019 were collected，and described statistically using the mortality rate，proportion of deaths by cause，potential years of life lost，potential years of life lost rate，and average years of life lost. Poisson regression model was adopted to estimate the trend in U5MR and its 95%CI during 5 years for three types of areas. Chi-square test was chosen to analyze the changes in death places during 5 years. The data source came from "population death information registration management system" of "China Disease Control and prevention information system" of Yunnan Center for Disease Control and Prevention. Results　U5MR in Yunnan had decreased by -28.23% for 5 years，at -7.60% per year on average〔95%CI（-8.52%，-6.76%）〕. The same decline trends happened in severely impoverished areas｛-29.51% for 5 years，-6.95% per year on average〔95%CI（-8.51%，-5.45%）〕｝，poor areas｛-13.34% for 5 years，-3.15% per year on average〔95%CI（-4.59%，-1.69%）〕｝，and non-poor areas｛-42.66% for 5 years，-13.76% per year on average〔95%CI（-15.38%，-12.10%）〕｝. The majority of under-5 deaths took place at home in severely impoverished areas，but the proportion had reduced by year. By contrast，the majority of under-5 deaths took place at hospital in poor areas and non-poor areas，and the proportions had reduced by year as well. The differences in death places among children under 5 years old in poor areas were statistically significant across years （P<0.05）. The top three causes of death were birth trauma and asphyxia，lower respiratory tract infection，and congenital heart disease in both 2015 and 2019. Low birth weight and birth trauma and asphyxia caused the highest average years of life lost. Conclusion　In Yunnan Province，the reported mortality rate of children under 5 years old showed a significant decrease in all three regions with different levels of poverty. Given that the disparities in child health between poor and non-poor areas have remained，and the massive loss of life years have caused due to early death，substantial efforts are needed in future to strengthen the capacity to provide perinatal care and to end preventable deaths among children under 5 years old in those underdeveloped areas that have been lifted out of poverty currently.

Key words: Child mortality, Children under 5 years old, Cause of death, Potential years of life lost, Poverty, Yunnan

摘要： 背景　过去几十年里中国政府为降低5岁以下儿童死亡取得了明显成效，但城乡之间仍存在差异。
目的　分析云南省不同地区2015—2019年5岁以下儿童主要死亡原因和减寿情况。方法　按2017年贫困发生率将云南省129个区（县）划分为深度贫困、一般贫困和非贫困三类地区；以云南省疾病预防控制中心“中国疾病预防控制信息系统”的“人口死亡信息登记管理系统”为数据来源，采用死亡率、死因构成比、潜在减寿年数、减寿率、平均减寿年数5个健康测量指标对2015—2019年云南省5岁以下儿童死亡报告数据进行统计描述；采用Poisson回归模型估计云南省各类地区死亡率的变化趋势；采用卡方检验比较各类地区5岁以下儿童死亡地点在不同年份间的差异。结果　云南省5岁以下儿童死亡率呈下降趋势，变化幅度为-28.23%，年均变化为-7.60%〔95%CI（-8.52%，-6.76%）〕。深度贫困地区、一般贫困地区和非贫困地区的5岁以下儿童死亡率变化幅度分别为-29.51%、-13.34%、-42.66%，年均变化分别为-6.95%〔95%CI（-8.51%，-5.45%）〕、-3.15%〔95%CI（-4.59%，-1.69%）〕、-13.76%〔95%CI（-15.38%，-12.10%）〕。5岁以下儿童在深度贫困地区的主要死亡地点为家中，但有下降趋势；一般贫困地区和非贫困地区的主要死亡地点为医疗机构，亦有下降趋势。贫困地区5岁以下儿童死亡地点在不同年份间的构成比较，差异有统计学意义（P<0.05）。云南省5岁以下儿童2015年和2019年的前三位死因均为出生产伤和窒息、下呼吸道感染及先天性心脏异常，但平均减寿年数值较高的主要为出生低体质量及出生产伤和窒息。结论　云南省5岁以下儿童死亡率在三类地区均呈下降趋势。但鉴于贫困与非贫困地区间仍存在差异，以及早死带来的寿命损失，未来仍需进一步采取干预措施，持续提升脱贫地区的卫生服务能力，同时强化围生期保健和意外死亡的防控。

关键词: 儿童死亡率, 5岁以下儿童, 死亡原因, 潜在寿命损失, 贫困, 云南