Wang Pin, Rogne Tormod, Warren Joshua L, Asare Ernest O, Akum Robert A, Toure N'datchoh E, Ross Joseph S, Chen Kai
Department of Environmental Health Sciences, Yale School of Public Health, New Haven, Connecticut, United States of America.
Yale Center on Climate Change and Health, Yale School of Public Health, New Haven, Connecticut, United States of America.
PLoS Med. 2025 Jan 31;22(1):e1004516. doi: 10.1371/journal.pmed.1004516. eCollection 2025 Jan.
As extreme events such as drought and flood are projected to increase in frequency and intensity under climate change, there is still large missing evidence on how drought exposure potentially impacts mortality among young children. This study aimed to investigate the association between drought and risk of infant mortality in Africa, a region highly vulnerable to climate change that bears the heaviest share of the global burden.
In this cross-sectional study, we obtained data on infant mortality in 34 African countries during 1992-2019 from the Demographic and Health Surveys program. We measured drought by the standardized precipitation evapotranspiration index at a timescale of 24 months and a spatial resolution of 10 × 10 km, which was further dichotomized into mild and severe drought. The association between drought exposure and infant mortality risk was estimated using Cox regression models allowing time-dependent covariates. We further examined whether the association varied for neonatal and post-neonatal mortality and whether there was a delayed association with drought exposure during pregnancy or infancy. The mean (standard deviation) number of months in which children experienced any drought during pregnancy and survival period (from birth through death before 1 year of age) was 4.6 (5.2) and 7.3 (7.4) among cases and non-cases, respectively. Compared to children who did not experience drought, we did not find evidence that any drought exposure was associated with an increased risk of infant mortality (hazard ratio [HR]: 1.02, 95% confidence interval [CI] [1.00, 1.04], p = 0.072). When stratified by drought severity, we found a statistically significant association with severe drought (HR: 1.04; 95% CI [1.01, 1.07], p = 0.015), but no significant association with mild drought (HR: 1.01; 95% CI [0.99, 1.03], p = 0.353), compared to non-exposure to any drought. However, when excluding drought exposure during pregnancy, the association with severe drought was found to be non-significant. In addition, an increased risk of neonatal mortality was associated with severe drought (HR: 1.05; 95% CI [1.01, 1.10], p = 0.019), but not with mild drought (HR: 0.99; 95% CI [0.96, 1.02], p = 0.657).
Exposure to long-term severe drought was associated with increased infant mortality risk in Africa. Our findings urge more effective adaptation measures and alleviation strategies against the adverse impact of drought on child health.
预计在气候变化的影响下，诸如干旱和洪水等极端事件的发生频率和强度将会增加，但关于干旱暴露如何潜在影响幼儿死亡率，仍有大量证据缺失。本研究旨在调查干旱与非洲婴儿死亡风险之间的关联，非洲是一个极易受气候变化影响且承担着全球最重负担份额的地区。
在这项横断面研究中，我们从人口与健康调查项目中获取了1992 - 2019年期间34个非洲国家的婴儿死亡率数据。我们采用24个月时间尺度和10×10千米空间分辨率的标准化降水蒸发散指数来衡量干旱，并将其进一步分为轻度干旱和重度干旱。使用允许时间依存协变量的Cox回归模型来估计干旱暴露与婴儿死亡风险之间的关联。我们进一步研究了这种关联在新生儿和新生儿后期死亡率中是否存在差异，以及在孕期或婴儿期干旱暴露是否存在延迟关联。在病例组和非病例组中，儿童在孕期和生存期（从出生到1岁前死亡）经历任何干旱的平均（标准差）月数分别为4.6（5.2）和7.3（7.4）。与未经历干旱暴露的儿童相比，我们没有发现任何干旱暴露与婴儿死亡风险增加相关的证据（风险比[HR]：1.02，95%置信区间[CI][1.00, 1.04]，p = 0.072）。按干旱严重程度分层时，我们发现与重度干旱存在统计学显著关联（HR：1.04；95% CI[1.01, 1.07]，p = 0.015），但与轻度干旱无显著关联（HR：1.01；95% CI[0.99, 1.03]，p = 0.353），与未暴露于任何干旱相比。然而，排除孕期干旱暴露后，发现与重度干旱的关联不显著。此外，重度干旱与新生儿死亡风险增加相关（HR：1.05；95% CI[1.01, 1.10]，p = 0.019），但与轻度干旱无关（HR：0.99；95% CI[0.96, 1.02]，p = 0.657）。
在非洲，长期暴露于严重干旱与婴儿死亡风险增加相关。我们的研究结果敦促采取更有效的适应措施和缓解策略，以应对干旱对儿童健康的不利影响。
