Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China.
National Center for Chronic and Noncommunicable Disease Control and Prevention, Beijing 100050, China.
Sci Total Environ. 2019 Feb 1;649:695-702. doi: 10.1016/j.scitotenv.2018.08.332. Epub 2018 Aug 26.
Few data are available on the health impacts of heatwaves in China, and in particular, the heatwave definition and vulnerable populations remain to be identified. We collected data on daily maximum temperature and mortality from 31 Chinese capital cities during 2007-2013. A Poisson regression model allowing for over-dispersion was applied to estimate the short-term effects of heatwaves on mortality in hot season (May-September). 15 heatwave definitions combining five heat thresholds (90.0th, 92.5th, 95th, 97.5th and 99th percentiles of daily maximum temperature) and three durations (≥2, ≥3 and ≥4 days) were compared. The pooled effects were then computed using random effect meta-analysis based on the residual maximum likelihood estimation. Effect modification of heatwave-mortality association by individual-level characteristics was tested using a stratified analysis. Potential effect modification by city-level characteristics was examined by meta-regression analysis. Totally, 259 million permanent residents were covered and 4,481,090 non-accidental deaths occurred during the study period. Generally, the magnitude of heatwave impacts increased by intensities and durations of the heatwaves. Heatwave definition using daily maximum temperature ≥ 92.5th percentile with duration ≥3 days produced the best model fit. The pooled relative risks of heatwaves on non-accidental mortality at lag 0, lag 0-2 and lag 0-10 days were 1.06 (95%CI: 1.03-1.09), 1.09 (1.05-1.13) and 1.10 (1.05-1.15), respectively. Compared with non-accidental mortality, higher effect estimates of heatwaves were observed among deaths from ischemic heart diseases, stroke and respiratory diseases, although the differences were not statistically significant. Females, those ≥75 years old and the illiterates were more vulnerable to heatwaves. Cities with higher concentrations of PM, higher latitudes, and lower numbers of hospital beds per 10,000 populations had higher mortality risks during heatwaves. These findings may have important implications for developing heat alert systems and early response actions on protecting the vulnerable populations from adverse health effects of heatwave in China.
在中国，有关热浪对健康影响的数据很少，特别是热浪的定义和脆弱人群仍有待确定。我们收集了 2007 年至 2013 年期间 31 个中国省会城市的每日最高温度和死亡率数据。应用泊松回归模型（允许过度分散）估计了热季（5 月至 9 月）热浪对死亡率的短期影响。比较了五种热阈值（每日最高温度的第 90.0、92.5、95、97.5 和 99 百分位数）和三种持续时间（≥2、≥3 和≥4 天）组合的 15 种热浪定义。然后，基于残差最大似然估计，使用随机效应荟萃分析计算汇总效应。使用分层分析测试了热浪-死亡率相关性的个体水平特征的效应修饰。通过荟萃回归分析检验了城市水平特征的潜在效应修饰。研究期间，共覆盖了 2.59 亿常住居民，发生了 448.109 例非意外死亡。一般来说，热浪影响的大小随着热浪的强度和持续时间的增加而增加。使用日最高温度≥92.5 百分位数且持续时间≥3 天的热浪定义产生了最佳的模型拟合。滞后 0、0-2 和 0-10 天的热浪对非意外死亡率的汇总相对风险分别为 1.06（95%CI：1.03-1.09）、1.09（1.05-1.13）和 1.10（1.05-1.15）。与非意外死亡率相比，在缺血性心脏病、中风和呼吸道疾病死亡中观察到热浪的更高影响估计，尽管差异没有统计学意义。女性、≥75 岁和文盲人群更容易受到热浪的影响。热浪期间，PM 浓度较高、纬度较高、每 10000 人口病床数较少的城市的死亡率较高。这些发现可能对制定热浪警报系统和采取早期应对措施保护中国脆弱人群免受热浪对健康的不利影响具有重要意义。
