Population Studies Center, University of Pennsylvania, Philadelphia, PA, USA.
Department of Population Health, London School of Hygiene & Tropical Medicine, London, UK.
Lancet Glob Health. 2022 Nov;10(11):e1566-e1574. doi: 10.1016/S2214-109X(22)00337-0. Epub 2022 Sep 8.
Understanding the age pattern of under-5 mortality is essential for identifying the most vulnerable ages and underlying causes of death, and for assessing why the decline in child mortality is slower in some countries and subnational areas than others. The aim of this study is to detect age patterns of under-5 mortality that are specific to low-income and middle-income countries (LMICs).
In this modelling study, we used data from 277 Demographic and Health Surveys (DHSs), 58 Health and Demographic Surveillance Systems (HDSSs), two cohort studies, and two sample-registration systems. From these sources, we collected child date of birth and date of death (or age at death) from LMICs between 1966 and 2020. We computed 22 deaths rates from each survey with the following age breakdowns: 0, 7, 14, 21, and 28 days; 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, 18, and 21 months; and 2, 3, 4, and 5 years. We assessed how probabilities of dying estimated for the 22 age groups deviated from predictions generated by a vital registration model that reflects the historical mortality of 25 high-income countries.
We calculated mortality rates of 81 LMICs between 1966 and 2020. In contrast with the other regions of the world, we found that under-5 mortality in south Asia and sub-Saharan Africa was characterised by increased mortality at both ends of the age range (ie, younger than 28 days and older than 6 months) at a given level of mortality. Observed mortality in these regions was up to 2 times higher than predicted by the vital registration model for the younger-than-28 days age bracket, and up to 10 times higher than predicted for the older-than-6 months age bracket. This age pattern of under-5 mortality is significant in 17 countries in south Asia and sub-Saharan Africa. Excess mortality in children older than 6 months without excess mortality in children younger than 28 days was found in 38 countries. In south Asia, results were consistent across data sources. In sub-Saharan Africa, excess mortality in children younger than 28 days was found mostly in DHSs; the majority of HDSSs did not show this excess mortality. We have attributed this difference in data sources mainly to omissions of early deaths in HDSSs.
In countries with age patterns of under-5 mortality that diverge from predictions, evidence-based public health interventions should focus on the causes of excess of mortality; notably, the effect of fetal growth restriction and infectious diseases. The age pattern of under-5 mortality will be instrumental in assessing progress towards the decline of under-5 mortality and the Sustainable Development Goals.
Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health.
了解五岁以下儿童死亡率的年龄模式对于确定最脆弱的年龄和死亡的根本原因，以及评估为什么一些国家和次国家地区的儿童死亡率下降速度比其他国家和地区慢，是至关重要的。本研究的目的是发现特定于低收入和中等收入国家（LMICs）的五岁以下儿童死亡率的年龄模式。
在这项建模研究中，我们使用了来自 1966 年至 2020 年期间 277 项人口与健康调查（DHSs）、58 项健康和人口监测系统（HDSSs）、两项队列研究和两项抽样登记系统的数据。从这些来源中，我们收集了来自 LMICs 的儿童出生日期和死亡日期（或死亡时的年龄）。我们根据以下年龄分组计算了来自每个调查的 22 个死亡率：0、7、14、21 和 28 天；2、3、4、5、6、7、8、9、10、11、12、15、18 和 21 个月；以及 2、3、4 和 5 岁。我们评估了估计的 22 个年龄组的死亡概率与反映 25 个高收入国家历史死亡率的生命登记模型生成的预测值之间的差异。
我们计算了 1966 年至 2020 年期间 81 个 LMICs 的死亡率。与世界其他地区不同，我们发现南亚和撒哈拉以南非洲的五岁以下儿童死亡率在给定死亡率水平下，在年龄范围的两端（即 28 天以下和 6 个月以上）都呈现出更高的死亡率。这些地区的观察死亡率比生命登记模型预测的 28 天以下年龄组的死亡率高出 2 倍，比 6 个月以上年龄组的死亡率高出 10 倍。这种五岁以下儿童死亡率的年龄模式在南亚和撒哈拉以南非洲的 17 个国家中具有显著意义。在 38 个国家中，6 个月以上儿童的死亡率过高，但 28 天以下儿童的死亡率没有过高。在南亚，不同数据源的结果是一致的。在撒哈拉以南非洲，28 天以下儿童的死亡率过高主要出现在 DHSs 中；大多数 HDSSs 没有显示出这种死亡率过高的情况。我们主要归因于 HDSSs 中早期死亡的遗漏造成了数据源的差异。
在五岁以下儿童死亡率的年龄模式与预测结果不一致的国家，循证公共卫生干预措施应侧重于死亡率过高的原因；特别是胎儿生长受限和传染病的影响。五岁以下儿童死亡率的年龄模式将有助于评估五岁以下儿童死亡率下降和可持续发展目标的进展情况。
美国国立卫生研究院国家儿童健康与人类发展研究所尤尼斯·肯尼迪·施莱佛国立儿童健康与人类发展研究所。
