National Institute of Environmental Health, Chinese Center for Disease Control and Prevention, No.7 PanjiayuanNanli, Chaoyang District, Beijing 100021, China.
Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523-1681, USA.
Environ Int. 2018 Feb;111:52-59. doi: 10.1016/j.envint.2017.10.023. Epub 2017 Nov 22.
Exposure to fine particulate matter (≤2.5μm in aerodynamic diameter; PM) has been shown to be associated with an increased risk of mortality due to cardiovascular, respiratory, and other pulmonary diseases. However, fewer studies have investigated the relationship between ambient PM and human mortality for a wider range of causes of death, or for more specific causes of death within these broader categories, especially at the high PM concentrations currently experienced in Chinese megacities. Beijing, China, has a very large population and a wide range of PM exposures, allowing a prime opportunity to estimate such risks across a broad spectrum of causes, including rarer causes of death.
To estimate the relative risk of cause-specific mortality associated with PM for a spectrum of causes of death, as well as characterize the time course of cause-specific mortality following PM exposure, in a location where PM concentrations are representative of common exposures in Chinese megacities.
We collected daily data on mortality counts of Beijing residents and Beijing weather and air pollution measurements for January 1, 2009 to December 31, 2012. We used a time-stratified case-crossover study design to estimate the association between ambient PM concentrations and risk of death from several broad causes of death and from more refined specific causes within these broader categories. Primary results were estimated for risks the day of and the day following exposure (lag 0-1), but the time pattern of associated risk was also explored up to seven days following exposure.
Increased concentrations of PM were associated with increased risks at lag days 0-1 of all-cause mortality (0.26% increase per 10μg/m; 95% confidence interval [CI]: 0.12%-0.39%), non-accidental deaths (0.25%; 95% CI: 0.11%-0.38%), circulatory deaths (0.39%; 95% CI: 0.21%-0.59%), respiratory deaths (0.43%; 95% CI: 0.05%-0.81%), intentional self-harm deaths (1.94%; 95% CI: 0.19%-3.73%) and nervous system deaths (0.9%; 95% CI: -0.2%-2%), although the observed increase was not statistical significant for the final one rarer cause of death. In addition to these five broad death outcomes, risk also increased following PM exposure at lag days 0-1 for deaths from several specific causes, including most of the specific circulatory causes considered. The largest observed increased risk by far was for one of the rarest causes of death considered, extrapyramidal and movement disorders (2.35%; 95% CI: 0.03%-4.72%).
This study indicates that exposure to PM in a study location more representative of exposures in developing cities is associated with an increased risk of mortality from broad range of causes of death, including some causes rarely studied previously in association with PM exposure.
细颗粒物（空气动力学直径≤2.5μm；PM）暴露已被证明与心血管、呼吸和其他肺部疾病导致的死亡率增加有关。然而，较少的研究调查了环境 PM 与更广泛的死亡原因范围内的人类死亡率之间的关系，或者在这些更广泛的类别内更具体的死亡原因之间的关系，特别是在当前中国特大城市中经历的高 PM 浓度下。中国北京人口众多，PM 暴露范围广泛，这为评估各种原因的风险提供了绝佳机会，包括更罕见的死亡原因。
评估与 PM 相关的特定原因死亡率的相对风险，以确定一系列死亡原因，并描述 PM 暴露后特定原因死亡率的时间进程，这是在 PM 浓度代表中国特大城市常见暴露的地点进行的。
我们收集了 2009 年 1 月 1 日至 2012 年 12 月 31 日期间北京居民的每日死亡人数和北京天气及空气污染测量数据。我们使用时间分层病例交叉研究设计来估计环境 PM 浓度与多种广泛的死亡原因以及这些更广泛类别内更具体原因的死亡风险之间的关联。主要结果是在暴露当天和暴露后第 1 天（滞后 0-1）估计的风险，但也探讨了暴露后长达 7 天的相关风险时间模式。
PM 浓度增加与所有原因死亡率（每 10μg/m 增加 0.26%；95%置信区间 [CI]：0.12%-0.39%）、非意外死亡（0.25%；95% CI：0.11%-0.38%）、循环系统死亡（0.39%；95% CI：0.21%-0.59%）、呼吸系统死亡（0.43%；95% CI：0.05%-0.81%）、故意自残死亡（1.94%；95% CI：0.19%-3.73%）和神经系统死亡（0.9%；95% CI：-0.2%-2%）的风险增加相关，尽管最后一个罕见的死亡原因观察到的增加并不具有统计学意义。除了这五个广泛的死亡结果外，PM 暴露后第 0-1 天的死亡率也增加了，包括考虑到的大多数特定循环系统原因。迄今为止观察到的最大风险增加是考虑到的最罕见的死亡原因之一，锥体外系和运动障碍（2.35%；95% CI：0.03%-4.72%）。
本研究表明，在更能代表发展中城市暴露情况的研究地点暴露于 PM 与更广泛的死亡原因导致的死亡率增加有关，包括以前很少有研究将 PM 暴露与一些原因联系起来的原因。
