University of California, San Diego-Herbert Wertheim School of Public Health, United States; San Diego State University, United States; Scripps Institution of Oceanography, United States.
University of California, San Diego-Herbert Wertheim School of Public Health, United States; San Diego State University, United States; Scripps Institution of Oceanography, United States; University of Washington, United States.
Environ Int. 2022 Jan;158:106902. doi: 10.1016/j.envint.2021.106902. Epub 2021 Oct 6.
Stillbirths and complications from preterm birth are two of the leading causes of neonatal deaths across the globe. Lower- to middle-income countries (LMICs) are experiencing some of the highest rates of these adverse birth outcomes. Research has suggested that environmental determinants, such as extreme heat, can increase the risk of preterm birth and stillbirth. Under climate change, extreme heat events have become more severe and frequent and are occurring in differential seasonal patterns. Little is known about how extreme heat affects the risk of preterm birth and stillbirth in LMICs. Thus, it is imperative to examine how exposure to extreme heat affects adverse birth outcomes in regions with some of the highest rates of preterm and stillbirths. Most of the evidence linking extreme heat and adverse birth outcomes has been generated from high-income countries (HICs) notably because measuring temperature in LMICs has proven challenging due to the scarcity of ground monitors. The paucity of health data has been an additional obstacle to study this relationship in LMICs. In this study, globally gridded meteorological data was linked with spatially and temporally resolved Demographic and Health Surveys (DHS) data on adverse birth outcomes. A global analysis of 14 LMICs was conducted per a pooled time-stratified case-crossover design with distributed-lag nonlinear models to ascertain the relationship between acute exposure to extreme heat and PTB and stillbirths. We notably found that experiencing higher maximum temperatures and smaller diurnal temperature range during the last week before birth increased the risk of preterm birth and stillbirth. This study is the first global assessment of extreme heat events and adverse birth outcomes and builds the evidence base for LMICs.
死产和早产并发症是全球新生儿死亡的两个主要原因。中低收入国家（LMICs）正经历着这些不良生育结局的一些最高发病率。研究表明，环境决定因素，如极端高温，可能会增加早产和死产的风险。在气候变化下，极端高温事件变得更加严重和频繁，而且发生的季节性模式也不同。目前还不清楚极端高温对 LMICs 早产和死产风险的影响。因此，迫切需要研究极端高温如何影响早产和死产率最高的地区的不良生育结局。将极端高温与不良生育结局联系起来的大部分证据来自高收入国家（HICs），这主要是因为由于缺乏地面监测，在 LMICs 中测量温度具有挑战性。卫生数据的缺乏是在 LMICs 中研究这种关系的另一个障碍。在这项研究中，全球网格化气象数据与空间和时间分辨率的人口与健康调查（DHS）不良生育结局数据相关联。采用时间分层病例交叉设计和分布式滞后非线性模型对 14 个 LMIC 进行了全球分析，以确定出生前最后一周内急性暴露于极端高温与 PTB 和死产之间的关系。我们特别发现，在出生前最后一周经历更高的最高温度和更小的日温差会增加早产和死产的风险。这项研究是对极端高温事件和不良生育结局的首次全球评估，并为 LMICs 建立了证据基础。
