Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia.
Institute of Advanced Studies, University of São Paulo, São Paulo, Brazil.
PLoS Med. 2019 Feb 22;16(2):e1002753. doi: 10.1371/journal.pmed.1002753. eCollection 2019 Feb.
To our knowledge, no study has assessed the association between heatwaves and risk of hospitalization and how it may change over time in Brazil. We quantified the heatwave-hospitalization association in Brazil during 2000-2015.
Daily data on hospitalization and temperature were collected from 1,814 cities (>78% of the national population) in the hottest five consecutive months during 2000-2015. Twelve types of heatwaves were defined with daily mean temperatures of ≥90th, 92.5th, 95th, or 97.5th percentiles of year-round temperature and durations of ≥2, 3, or 4 consecutive days. The city-specific association was estimated using a quasi-Poisson regression with constrained distributed lag model and then pooled at the national level using random-effect meta-analysis. Stratified analyses were performed by five regions, sex, 10 age groups, and nine cause categories. The temporal change in the heatwave-hospitalization association was assessed using a time-varying constrained distributed lag model. Of the 58,400,682 hospitalizations (59% women), 24%, 34%, 21%, and 19% of cases were aged <20, 20-39, 40-59, and ≥60 years, respectively. The city-specific year-round daily mean temperatures were 23.5 ± 2.8 °C on average, varying from 26.8 ± 1.8 °C for the 90th percentile to 28.0 ± 1.6 °C for the 97.5th percentile. We observed that the risk of hospitalization was most pronounced for heatwaves characterized by high daily temperatures and long durations across Brazil, except for the minimal association in the north (the hottest region). After controlling for temperature, the association remained for severe heatwaves in the south and southeast (cold regions). Children 0-9 years, the elderly ≥70 years, and admissions for perinatal conditions were most strongly associated with heatwaves. Over the study period, the strength of the heatwave-hospitalization association declined substantially in the south, while an apparent increase was observed in the southeast. The main limitations of this study included the lack of data on individual temperature exposure and measured air pollution.
There are geographic, demographic, cause-specific, and temporal variations in the heatwave-hospitalization associations across the Brazilian population. Considering the projected increase in frequency, duration, and intensity of heatwaves, future strategies should be developed, such as building early warning systems, to reduce the health risk associated with heatwaves in Brazil.
据我们所知，尚无研究评估热浪与住院风险之间的关联，以及这种关联在巴西可能随时间的变化。我们量化了 2000-2015 年期间巴西热浪与住院之间的关联。
我们收集了 2000-2015 年期间最炎热的五个月中，1814 个城市（占全国人口的>78%）每日的住院和温度数据。用日平均温度≥全年温度的第 90、92.5、95 或 97.5 百分位数，并持续 2、3 或 4 天，定义了 12 种热浪类型。使用具有约束分布滞后模型的拟泊松回归估计城市特定的关联，然后使用随机效应荟萃分析在全国范围内进行汇总。按五个地区、性别、10 个年龄组和九个病因类别进行分层分析。使用时变约束分布滞后模型评估热浪与住院之间关联的时间变化。在 58400682 例住院治疗（59%为女性）中，分别有 24%、34%、21%和 19%的病例年龄<20 岁、20-39 岁、40-59 岁和≥60 岁。城市全年每日平均温度平均为 23.5±2.8°C，范围从第 90 百分位数的 26.8±1.8°C到第 97.5 百分位数的 28.0±1.6°C。我们发现，除了北部（最炎热的地区）关联最小外，在巴西各地，高温和长时间的热浪对住院的风险影响最大。在控制温度后，南部和东南部（寒冷地区）的严重热浪仍存在关联。0-9 岁的儿童、≥70 岁的老年人以及围产期疾病的入院与热浪的关联最为密切。在研究期间，南部地区热浪与住院之间的关联强度大幅下降，而东南部地区则明显上升。本研究的主要局限性包括缺乏个体温度暴露和测量空气污染的数据。
巴西人口热浪与住院之间的关联存在地域、人口统计学、病因特异性和时间上的差异。考虑到热浪的频率、持续时间和强度预计会增加，未来应制定策略，例如建立早期预警系统，以降低巴西热浪对健康的风险。
