Department of Hematology, Fourth Affiliated Hospital of Nantong University, First Hospital of Yancheng, Yancheng, China.
J Epidemiol. 2012;22(1):28-36. doi: 10.2188/jea.je20110049. Epub 2011 Oct 29.
Both outdoor air pollution and extreme temperature have been associated with daily mortality; however, the effect of their interaction is not known.
This time-series analysis examined the effect of the interaction between outdoor air pollutants and extreme temperature on daily mortality in Shanghai, China. A generalized additive model (GAM) with penalized splines was used to analyze mortality, air pollution, temperature, and covariate data. The effects of air pollutants were stratified by temperature stratum to examine the interaction effect of air pollutants and extreme temperature.
We found a statistically significant interaction between PM₁₀/O₃ and extreme low temperatures for both total nonaccidental and cause-specific mortality. On days with "normal" temperatures (15th-85th percentile), a 10-µg/m³ increment in PM₁₀ corresponded to a 0.17% (95% CI: 0.03%, 0.32%) increase in total mortality, a 0.23% (0.02%, 0.44%) increase in cardiovascular mortality, and a 0.26% (-0.07%, 0.60%) increase in respiratory mortality. On low-temperature days (<15th percentile), the estimates changed to 0.40% (0.21%, 0.58%) for total mortality, 0.49% (0.13%, 0.86%) for cardiovascular mortality, and 0.24% (-0.33%, 0.82%) for respiratory mortality. The interaction pattern of O₃ with lower temperature was similar. The interaction between PM₁₀/O₃ and lower temperature remained robust when alternative cut-points were used for temperature strata.
The acute health effects of air pollution might vary by temperature level.
户外空气污染和极端温度都与每日死亡率有关；然而，它们相互作用的影响尚不清楚。
本时间序列分析考察了户外空气污染物与极端温度对中国上海每日死亡率的相互作用影响。广义相加模型（GAM）与惩罚样条一起用于分析死亡率、空气污染、温度和协变量数据。按温度层划分污染物的影响，以检查空气污染物与极端温度的相互作用效应。
我们发现 PM₁₀/O₃ 与极端低温之间存在统计学上显著的相互作用，对总非意外和特定原因死亡率均有影响。在“正常”温度（第 15-85 百分位数）天，PM₁₀ 增加 10μg/m³，总死亡率增加 0.17%（95%CI：0.03%，0.32%），心血管死亡率增加 0.23%（0.02%，0.44%），呼吸死亡率增加 0.26%（-0.07%，0.60%）。在低温天（<15 百分位数），估计值变为总死亡率增加 0.40%（0.21%，0.58%），心血管死亡率增加 0.49%（0.13%，0.86%），呼吸死亡率增加 0.24%（-0.33%，0.82%）。O₃ 与较低温度的相互作用模式相似。当替代温度层的切点时，PM₁₀/O₃ 与较低温度之间的相互作用仍然稳健。
空气污染的急性健康影响可能因温度水平而异。
