Department of Epidemiology, School of Public Health and Management, Binzhou Medical University, Yantai, Shandong, China.
Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
PLoS Med. 2019 Oct 29;16(10):e1002950. doi: 10.1371/journal.pmed.1002950. eCollection 2019 Oct.
Global warming is predicted to indirectly result in more undernutrition by threatening crop production. Whether temperature rise could affect undernutrition directly is unknown. We aim to quantify the relationship between short-term heat exposure and risk of hospitalization due to undernutrition in Brazil.
We collected hospitalization and weather data for the hot season (the 4 adjacent hottest months for each city) from 1,814 Brazilian cities during 1 January 2000-31 December 2015. We used a time-stratified case-crossover design to quantify the association between heat exposure and hospitalization due to undernutrition. Region-specific odds ratios (ORs) were used to calculate the attributable fractions (AFs). A total of 238,320 hospitalizations for undernutrition were recorded during the 2000-2015 hot seasons. Every 1°C increase in daily mean temperature was associated with a 2.5% (OR 1.025, 95% CI 1.020-1.030, p < 0.001) increase in hospitalizations for undernutrition across lag 0-7 days. The association was greatest for individuals aged ≥80 years (OR 1.046, 95% CI 1.034-1.059, p < 0.001), 0-4 years (OR 1.039, 95% CI 1.024-1.055, p < 0.001), and 5-19 years (OR 1.042, 95% CI 1.015-1.069, p = 0.002). Assuming a causal relationship, we estimate that 15.6% of undernutrition hospitalizations could be attributed to heat exposure during the study period. The AF grew from 14.1% to 17.5% with a 1.1°C increase in mean temperature from 2000 to 2015. The main limitations of this study are misclassification of different types of undernutrition, lack of individual temperature exposure data, and being unable to adjust for relative humidity.
Our study suggests that global warming might directly increase undernutrition morbidity, by a route other than by threatening food security. This short-term effect is increasingly important with global warming. Global strategies addressing the syndemic of climate change and undernutrition should focus not only on food systems, but also on the prevention of heat exposure.
全球变暖预计将通过威胁作物生产而间接导致更多的营养不足。气温升高是否会直接导致营养不足尚不清楚。我们旨在量化短期热暴露与巴西因营养不足住院风险之间的关系。
我们收集了 2000 年 1 月 1 日至 2015 年 12 月 31 日期间 1814 个巴西城市的热季（每个城市相邻的 4 个最热月份）的住院和天气数据。我们使用时间分层病例交叉设计来量化热暴露与营养不足住院之间的关联。使用区域特异性比值比 (OR) 计算归因分数 (AF)。在 2000-2015 年的热季期间，共记录了 238320 例营养不足住院病例。每日平均气温每升高 1°C，营养不足住院的风险就会增加 2.5%（OR 1.025，95%CI 1.020-1.030，p<0.001）。滞后 0-7 天的关联最大。对于年龄≥80 岁的个体（OR 1.046，95%CI 1.034-1.059，p<0.001）、0-4 岁（OR 1.039，95%CI 1.024-1.055，p<0.001）和 5-19 岁（OR 1.042，95%CI 1.015-1.069，p=0.002）的个体，这种关联最大。假设存在因果关系，我们估计在研究期间，15.6%的营养不足住院可归因于热暴露。随着 2000 年至 2015 年平均气温升高 1.1°C，AF 从 14.1%增长到 17.5%。本研究的主要局限性是不同类型的营养不足的分类错误、缺乏个体温度暴露数据以及无法调整相对湿度。
我们的研究表明，全球变暖可能通过除了威胁粮食安全以外的其他途径直接增加营养不足的发病率。随着全球变暖，这种短期影响变得越来越重要。解决气候变化和营养不足综合问题的全球战略不仅应关注粮食系统，还应关注预防热暴露。
